Friday, July 18, 2014

Astronomers Confounded By Massive Rocky World

Astronomers Confounded By Massive Rocky World:

Kepler-10 system
An artist's conception shows the Kepler-10 system, home to two rocky planets. In the foreground is Kepler-10c, a planet that weighs 17 times as much as Earth and is more than twice as large in size. Planet formation theorists are challenged to explain how such a massive world could have formed. Credit: Harvard-Smithsonian Center for Astrophysics/David Aguilar

› Full image and caption


June 02, 2014

Astronomers have discovered a rocky planet that weighs 17 times as much as Earth and is more than twice as large in size. This discovery has planet formation theorists challenged to explain how such a world could have formed.

"We were very surprised when we realized what we had found," said astronomer Xavier Dumusque of the Harvard-Smithsonian Center for Astrophysics, Cambridge, Massachusetts, who led the analysis using data originally collected by NASA's Kepler space telescope.

Kepler-10c, as the planet had been named, had a previously measured size of 2.3 times larger than Earth, but its mass was not known until now. The team used the HARPS-North instrument on the Telescopio Nazionale Galileo in the Canary Islands to conduct follow-up observations to obtain a mass measurement of the rocky behemoth.

It was thought worlds such as this could not possibly exist. The enormous gravitational force of such a massive body would accrete a gas envelope during formation, ballooning the planet to a gas giant the size of Neptune or even Jupiter. However, this planet is thought to be solid, composed primarily of rock.

"Just when you think you've got it all figured out, nature gives you a huge surprise -- in this case, literally," said Natalie Batalha, Kepler mission scientist at NASA's Ames Research Center in Moffett Field, California. "Isn't science marvelous?"

Kepler-10c orbits a sun-like star every 45 days, making it too hot to sustain life as we know it. It is located about 560 light-years from Earth in the constellation Draco. The system also hosts Kepler-10b, the first rocky planet discovered in the Kepler data.

The finding was presented today at a meeting of the American Astronomical Society in Boston. Read more about the discovery in the Harvard-Smithsonian Center for Astrophysics news release.

NASA's Ames Research Center manages Kepler's ground system development, mission operations and science data analysis. NASA's Jet Propulsion Laboratory, Pasadena, California, managed the Kepler mission's development.

Ball Aerospace and Technologies Corp. in Boulder, Colorado, developed the Kepler flight system and supports mission operations with the Laboratory for Atmospheric and Space Physics at the University of Colorado in Boulder.

The Space Telescope Science Institute in Baltimore archives, hosts and distributes Kepler science data. Kepler is NASA's 10th Discovery Mission and is funded by NASA's Science Mission Directorate at the agency's headquarters in Washington.

For more information about the Kepler mission, visit:

http://www.nasa.gov/kepler

For more information about exoplanets and NASA's planet-finding program, visit:

http://planetquest.jpl.nasa.gov

Whitney Clavin 818-354-4673

Jet Propulsion Laboratory, Pasadena, Calif.

whitney.clavin@jpl.nasa.gov


2014-171
Posted by Nelio Inacio at 7:45 AM 0 comments

Herschel Sees Budding Stars and a Giant, Strange Ring

Herschel Sees Budding Stars and a Giant, Strange Ring:

A Puzzling Cosmic Ring
The Herschel Space Observatory has uncovered a weird ring of dusty material while obtaining one of the sharpest scans to date of a huge cloud of gas and dust, called NGC 7538. Image credit: ESA/NASA/JPL-Caltech/Whitman College
› Full image and caption


June 12, 2014

The Herschel Space Observatory has uncovered a weird ring of dusty material while obtaining one of the sharpest scans to date of a huge cloud of gas and dust, called NGC 7538. The observations have revealed numerous clumps of material, a baker's dozen of which may evolve into the most powerful kinds of stars in the universe. Herschel is a European Space Agency mission with important NASA contributions.

"We have looked at NGC 7538 with Herschel and identified 13 massive, dense clumps where colossal stars could form in the future," said paper lead author Cassandra Fallscheer, a visiting assistant professor of astronomy at Whitman College in Walla Walla, Washington, and lead author of the paper published in The Astrophysical Journal. "In addition, we have found a gigantic ring structure and the weird thing is, we're not at all sure what created it."

NGC 7538 is relatively nearby, at a distance of about 8,800 light-years and located in the constellation Cepheus. The cloud, which has a mass on the order of 400,000 suns, is undergoing an intense bout of star formation. Astronomers study stellar nurseries such as NGC 7538 to better learn how stars come into being. Finding the mysterious ring, in this case, came as an unexpected bonus.

The cool, dusty ring has an oval shape, with its long axis spanning about 35 light-years and its short axis about 25 light-years. Fallscheer and her colleagues estimate that the ring possesses the mass of 500 suns. Additional data from the James Clerk Maxwell Telescope, located at the Mauna Kea Observatory in Hawaii, further helped characterize the odd ovoid. Astronomers often see ring and bubble-like structures in cosmic dust clouds. The strong winds cast out by the most massive stars, called O-type stars, can generate these expanding puffs, as can their explosive deaths as supernovas. But no energetic source or remnant of a deceased O-type star, such as a neutron star, is apparent within the center of this ring. It is possible that a big star blew the bubble and, because stars are all in motion, subsequently left the scene, escaping detection.

The observations were taken as part of the Herschel OB Young Stellar objects (HOBYS) Key Programme. The "OB" refers to the two most massive kinds of stars, O-type and B-type. These bright blue, superhot, short-lived stars end up exploding as supernovas, leaving behind either incredibly dense neutron stars or even denser black holes.

Stars of this caliber form from gassy, dusty clumps with initial masses dozens of times greater than the sun's; the 13 clumps spotted in NGC 7358, some of which lie along the edge of the mystery ring, all are more than 40 times more massive than the sun. The clumps gravitationally collapse in on themselves, growing denser and hotter in their cores until nuclear fusion ignites and a star is born. For now, early in the star-formation process, the clumps remain quite cold, just a few tens of degrees above absolute zero. At these temperatures, the clumps emit the bulk of their radiation in the low-energy, submillimeter and infrared light that Herschel was specifically designed to detect.

As astronomers continue probing these budding O-type giants in NGC 7358, the follow-up observations with other telescopes should also help in solving the puzzle of the humongous, dusty ring. "Further research to determine the mechanism responsible for creating the ring structure is necessary," said Fallscheer.

Herschel is a European Space Agency mission, with science instruments provided by consortia of European institutes and with important participation by NASA. While the observatory stopped making science observations in April 2013, after running out of liquid coolant as expected, scientists continue to analyze its data. NASA's Herschel Project Office is based at the Jet Propulsion Laboratory in Pasadena, California. JPL contributed mission-enabling technology for two of Herschel's three science instruments. The NASA Herschel Science Center, part of the Infrared Processing and Analysis Center at the California Institute of Technology in Pasadena, supports the U.S. astronomical community.

More information is online at:

http://www.herschel.caltech.edu

http://www.nasa.gov/herschel

http://www.esa.int/SPECIALS/Herschel

Whitney Clavin 818-354-4673

Jet Propulsion Laboratory, Pasadena, Calif.

whitney.clavin@jpl.nasa.gov


2014-189
Posted by Nelio Inacio at 7:44 AM 0 comments

Giant Telescopes Pair Up to Image Near-Earth Asteroid

Giant Telescopes Pair Up to Image Near-Earth Asteroid:

Radar images of Asteroid 2014 HQ124
NASA scientists used Earth-based radar to produce these sharp views - an image montage and a movie sequence -- of the asteroid designated '2014 HQ124' on June 8, 2014. Image Credit: NASA/JPL-Caltech/Arecibo Observatory/USRA/NSF
› Full image and caption


June 12, 2014

NASA scientists using Earth-based radar have produced sharp views of a recently discovered asteroid as it slid silently past our planet. Captured on June 8, 2014, the new views of the object designated "2014 HQ124" are some of the most detailed radar images of a near-Earth asteroid ever obtained.

An animation of the rotating asteroid and a collage of the images are available at:

http://www.jpl.nasa.gov/video/index.php?id=1310

The radar observations were led by scientists Marina Brozovic and Lance Benner of NASA's Jet Propulsion Laboratory, Pasadena, California. The JPL researchers worked closely with Michael Nolan, Patrick Taylor, Ellen Howell and Alessondra Springmann at Arecibo Observatory in Puerto Rico to plan and execute the observations.

According to Benner, 2014 HQ124 appears to be an elongated, irregular object that is at least 1,200 feet (370 meters) wide on its long axis. "This may be a double object, or 'contact binary,' consisting of two objects that form a single asteroid with a lobed shape," he said. The images reveal a wealth of other features, including a puzzling pointy hill near the object's middle, on top as seen in the images.

The 21 radar images were taken over a span of four-and-a-half hours. During that interval, the asteroid rotated a few degrees per frame, suggesting its rotation period is slightly less than 24 hours.

At its closest approach to Earth on June 8, the asteroid came within 776,000 miles (1.25 million kilometers), or slightly more than three times the distance to the moon. Scientists began observations of 2014 HQ124 shortly after the closest approach, when the asteroid was between about 864,000 miles and 902,000 miles (1.39 million kilometers and 1.45 million kilometers) from Earth.

Each image in the collage and movie represents 10 minutes of data.

The new views show features as small as about 12 feet (3.75 meters) wide. This is the highest resolution currently possible using scientific radar antennas to produce images. Such sharp views for this asteroid were made possible by linking together two giant radio telescopes to enhance their capabilities.

To obtain the new views, researchers paired the 230-foot (70-meter) Deep Space Network antenna at Goldstone, California, with two other radio telescopes, one at a time. Using this technique, the Goldstone antenna beams a radar signal at an asteroid and the other antenna receives the reflections. The technique dramatically improves the amount of detail that can be seen in radar images.

To image 2014 HQ124, the researchers first paired the large Goldstone antenna with the 1,000-foot (305-meter) Arecibo radio telescope in Puerto Rico. They later paired the large Goldstone dish with a smaller companion, a 112-foot (34-meter) antenna, located about 20 miles (32 kilometers) away.

A recent equipment upgrade at Arecibo enabled the two facilities to work in tandem to obtain images with this fine level of detail for the first time.

"By itself, the Goldstone antenna can obtain images that show features as small as the width of a traffic lane on the highway," said Benner. "With Arecibo now able to receive our highest-resolution Goldstone signals, we can create a single system that improves the overall quality of the images."

The first five images in the new sequence -- the top row in the collage -- represent the data collected by Arecibo, and are 30 times brighter than what Goldstone can produce observing on its own.

Scientists were fortunate to be able to make these radar observations at all, as this particular asteroid was only recently discovered. NASA's NEOWISE mission, a space telescope adapted for scouting the skies for the infrared light emitted by asteroids and comets, first spotted the space rock on April 23, 2014. Additional information about the asteroid's discovery and its orbit was shared in a previous Web story online at:

http://www.jpl.nasa.gov/news/news.php?release=2014-178

For asteroids, as well as comets, radar is a powerful tool for studying the objects' size, shape, rotation, surface features and orbits. Radar measurements of asteroid distances and velocities enable researchers to compute orbits much further into the future than if radar observations were not available.

NASA detects, tracks and characterizes asteroids and comets passing close to Earth using both ground- and space-based telescopes. The Near-Earth Object Program, commonly called "Spaceguard," discovers these objects, characterizes a subset of them and identifies their orbits to determine if any could be potentially hazardous to our planet. To date, U.S. assets have discovered more than 98 percent of the known near-Earth objects.

Along with the resources NASA puts into understanding asteroids, it also partners with other U.S. government agencies, university-based astronomers and space science institutes across the country that are working to find, track and understand these objects better, often with grants, interagency transfers and other contracts from NASA. In addition, NASA values the work of numerous highly skilled amateur astronomers, whose accurate observational data helps improve asteroid orbits after they are found.

The contributions of JPL engineers Jon Giorgini, Joseph Jao and Clement Lee were critical to the successful execution of these observations.

Through its Asteroid Initiative, NASA is developing a first-ever mission to identify, capture and redirect a near-Earth asteroid to a stable orbit around the moon with a robotic spacecraft. Astronauts aboard an Orion spacecraft, launched by a Space Launch System rocket, will explore the asteroid in the 2020s, returning to Earth with samples. Experience in human spaceflight beyond low-Earth orbit through this Asteroid Redirect Mission will help NASA test new systems and capabilities needed to support future human missions to Mars. The Initiative also includes an Asteroid Grand Challenge, which is seeking the best ideas to find all asteroid threats to human populations and accelerate the work NASA already is doing for planetary defense.

JPL manages the Near-Earth Object Program Office for NASA's Science Mission Directorate in Washington. JPL is a division of the California Institute of Technology in Pasadena.

More information about asteroids and near-Earth objects is available at:

http://neo.jpl.nasa.gov/

http://www.jpl.nasa.gov/asteroidwatch

Twitter updates are at:

http://www.twitter.com/asteroidwatch

Preston Dyches 818-354-7013

Jet Propulsion Laboratory, Pasadena, Calif.

preston.dyches@jpl.nasa.gov


2014-186
Posted by Nelio Inacio at 7:42 AM 0 comments

New NASA Space Observatory to Study Carbon Conundrums

New NASA Space Observatory to Study Carbon Conundrums:

Artist's rendering of NASA's Orbiting Carbon Observatory (OCO)-2
Artist's rendering of NASA's Orbiting Carbon Observatory (OCO)-2, one of five new NASA Earth science missions set to launch in 2014, and one of three managed by JPL. Image credit: NASA/JPL-Caltech
› Larger image


June 12, 2014

NASA's first spacecraft dedicated to measuring carbon dioxide levels in Earth's atmosphere is in final preparations for a July 1 launch from Vandenberg Air Force Base, California.

The Orbiting Carbon Observatory-2 (OCO-2) mission will provide a more complete, global picture of the human and natural sources of carbon dioxide, as well as carbon dioxide's "sinks," the natural ocean and land processes by which carbon dioxide is pulled out of Earth's atmosphere and stored. Carbon dioxide, a critical component of Earth's carbon cycle, is the leading human-produced greenhouse gas driving changes in Earth's climate.

"Carbon dioxide in the atmosphere plays a critical role in our planet's energy balance and is a key factor in understanding how our climate is changing," said Michael Freilich, director of NASA's Earth Science Division in Washington. "With the OCO-2 mission, NASA will be contributing an important new source of global observations to the scientific challenge of better understanding our Earth and its future."

OCO-2 will launch on a United Launch Alliance Delta II rocket and maneuver into a 438-mile (705-kilometer) altitude, near-polar orbit. It will become the lead satellite in a constellation of five other international Earth monitoring satellites that circle Earth once every 99 minutes and cross the equator each day near 1:36 p.m. local time, making a wide range of nearly simultaneous Earth observations. OCO-2 is designed to operate for at least two years.

The spacecraft will sample the global geographic distribution of the sources and sinks of carbon dioxide and allow scientists to study their changes over time more completely than can be done with any existing data. Since 2009, Earth scientists have been preparing for OCO-2 by taking advantage of observations from the Japanese GOSAT satellite. OCO-2 replaces a nearly identical NASA spacecraft lost because of a rocket launch mishap in February 2009.

At approximately 400 parts per million, atmospheric carbon dioxide is now at its highest level in at least the past 800,000 years. The burning of fossil fuels and other human activities are currently adding nearly 40 billion tons of carbon dioxide to the atmosphere each year, producing an unprecedented buildup in this greenhouse gas.

Greenhouse gases trap the sun's heat within Earth's atmosphere, warming the planet's surface and helping to maintain habitable temperatures from the poles to the equator. Scientists have concluded increased carbon dioxide from human activities, particularly fossil fuel burning and deforestation, has thrown Earth's natural carbon cycle off balance, increasing global surface temperatures and changing our planet's climate.

Currently, less than half the carbon dioxide emitted into Earth's atmosphere by human activities stays there. Some of the remainder is absorbed by Earth's ocean, but the location and identity of the natural land sinks believed to be absorbing the rest are not well understood. OCO-2 scientists hope to coax these sinks out of hiding and resolve a longstanding scientific puzzle.

"Knowing what parts of Earth are helping remove carbon from our atmosphere will help us understand whether they will keep doing so in the future," said Michael Gunson, OCO-2 project scientist at NASA's Jet Propulsion Laboratory, Pasadena, California. "Understanding the processes controlling carbon dioxide in our atmosphere will help us predict how fast it will build up in the future. Data from this mission will help scientists reduce uncertainties in forecasts of how much carbon dioxide will be in the atmosphere and improve the accuracy of global climate change predictions."

OCO-2 measurements will be combined with data from ground stations, aircraft and other satellites to help answer questions about the processes that regulate atmospheric carbon dioxide and its role in Earth's climate and carbon cycle. Mission data will also help assess the usefulness of space-based measurements of carbon dioxide for monitoring emissions.

The observatory's science instrument features three high-resolution spectrometers that spread reflected sunlight into its component colors and then precisely measure the intensity of each color. Each spectrometer is optimized to record a different, specific color absorbed by carbon dioxide and oxygen molecules in Earth's atmosphere. The less carbon dioxide in the atmosphere, the more light the spectrometers detect. By analyzing the amount of light, scientists can estimate the relative concentrations of these chemicals.

The new observatory will dramatically increase the number of observations of carbon dioxide, collecting hundreds of thousands of measurements each day when the satellite flies over Earth's sunlit hemisphere. High-precision, detailed, near-global observations are needed to characterize carbon dioxide's distribution because the concentration of carbon dioxide varies by only a few percent throughout the year on regional to continental scales. Scientists will analyze the OCO-2 data, using computer models similar to those used to predict the weather, to locate and understand the sources and sinks of carbon dioxide.

OCO-2 is a NASA Earth System Science Pathfinder Program mission managed by JPL for NASA's Science Mission Directorate in Washington. Orbital Sciences Corporation in Dulles, Virginia, built the spacecraft bus and provides mission operations under JPL's leadership. The science instrument was built by JPL, based on the instrument design co-developed for the original OCO mission by Hamilton Sundstrand in Pomona, California. NASA's Launch Services Program at NASA's Kennedy Space Center in Florida is responsible for launch management. JPL is managed for NASA by the California Institute of Technology in Pasadena.

For more information about the Orbiting Carbon Observatory-2, visit:

http://oco.jpl.nasa.gov

and

http://www.nasa.gov/oco2

Follow OCO-2 on Twitter at:

https://twitter.com/IamOCO2

OCO-2 is the second of five NASA Earth science missions to be launched this year. NASA monitors Earth's vital signs from land, air and space with a fleet of satellites and ambitious airborne and ground-based observation campaigns. NASA develops new ways to observe and study Earth's interconnected natural systems with long-term data records and computer analysis tools to better see how our planet is changing. The agency shares this unique knowledge with the global community and works with institutions in the United States and around the world that contribute to understanding and protecting our home planet.

For more information about NASA's Earth science activities in 2014, visit:

http://www.nasa.gov/earthrightnow

Alan Buis

Jet Propulsion Laboratory, Pasadena, California

818-354-0474

alan.buis@jpl.nasa.gov


Steve Cole

NASA Headquarters, Washington

202-358-0918


2014-187
Posted by Nelio Inacio at 7:42 AM 0 comments

Herschel Sees Budding Stars and a Giant, Strange Ring

Herschel Sees Budding Stars and a Giant, Strange Ring:

A Puzzling Cosmic Ring
The Herschel Space Observatory has uncovered a weird ring of dusty material while obtaining one of the sharpest scans to date of a huge cloud of gas and dust, called NGC 7538. Image credit: ESA/NASA/JPL-Caltech/Whitman College
› Full image and caption


June 12, 2014

The Herschel Space Observatory has uncovered a weird ring of dusty material while obtaining one of the sharpest scans to date of a huge cloud of gas and dust, called NGC 7538. The observations have revealed numerous clumps of material, a baker's dozen of which may evolve into the most powerful kinds of stars in the universe. Herschel is a European Space Agency mission with important NASA contributions.

"We have looked at NGC 7538 with Herschel and identified 13 massive, dense clumps where colossal stars could form in the future," said paper lead author Cassandra Fallscheer, a visiting assistant professor of astronomy at Whitman College in Walla Walla, Washington, and lead author of the paper published in The Astrophysical Journal. "In addition, we have found a gigantic ring structure and the weird thing is, we're not at all sure what created it."

NGC 7538 is relatively nearby, at a distance of about 8,800 light-years and located in the constellation Cepheus. The cloud, which has a mass on the order of 400,000 suns, is undergoing an intense bout of star formation. Astronomers study stellar nurseries such as NGC 7538 to better learn how stars come into being. Finding the mysterious ring, in this case, came as an unexpected bonus.

The cool, dusty ring has an oval shape, with its long axis spanning about 35 light-years and its short axis about 25 light-years. Fallscheer and her colleagues estimate that the ring possesses the mass of 500 suns. Additional data from the James Clerk Maxwell Telescope, located at the Mauna Kea Observatory in Hawaii, further helped characterize the odd ovoid. Astronomers often see ring and bubble-like structures in cosmic dust clouds. The strong winds cast out by the most massive stars, called O-type stars, can generate these expanding puffs, as can their explosive deaths as supernovas. But no energetic source or remnant of a deceased O-type star, such as a neutron star, is apparent within the center of this ring. It is possible that a big star blew the bubble and, because stars are all in motion, subsequently left the scene, escaping detection.

The observations were taken as part of the Herschel OB Young Stellar objects (HOBYS) Key Programme. The "OB" refers to the two most massive kinds of stars, O-type and B-type. These bright blue, superhot, short-lived stars end up exploding as supernovas, leaving behind either incredibly dense neutron stars or even denser black holes.

Stars of this caliber form from gassy, dusty clumps with initial masses dozens of times greater than the sun's; the 13 clumps spotted in NGC 7358, some of which lie along the edge of the mystery ring, all are more than 40 times more massive than the sun. The clumps gravitationally collapse in on themselves, growing denser and hotter in their cores until nuclear fusion ignites and a star is born. For now, early in the star-formation process, the clumps remain quite cold, just a few tens of degrees above absolute zero. At these temperatures, the clumps emit the bulk of their radiation in the low-energy, submillimeter and infrared light that Herschel was specifically designed to detect.

As astronomers continue probing these budding O-type giants in NGC 7358, the follow-up observations with other telescopes should also help in solving the puzzle of the humongous, dusty ring. "Further research to determine the mechanism responsible for creating the ring structure is necessary," said Fallscheer.

Herschel is a European Space Agency mission, with science instruments provided by consortia of European institutes and with important participation by NASA. While the observatory stopped making science observations in April 2013, after running out of liquid coolant as expected, scientists continue to analyze its data. NASA's Herschel Project Office is based at the Jet Propulsion Laboratory in Pasadena, California. JPL contributed mission-enabling technology for two of Herschel's three science instruments. The NASA Herschel Science Center, part of the Infrared Processing and Analysis Center at the California Institute of Technology in Pasadena, supports the U.S. astronomical community.

More information is online at:

http://www.herschel.caltech.edu

http://www.nasa.gov/herschel

http://www.esa.int/SPECIALS/Herschel

Whitney Clavin 818-354-4673

Jet Propulsion Laboratory, Pasadena, Calif.

whitney.clavin@jpl.nasa.gov


2014-189
Posted by Nelio Inacio at 7:42 AM 0 comments

Titan Flybys Test the Talents of NASA's Cassini Team

Titan Flybys Test the Talents of NASA's Cassini Team:

Artist's concept of Titan flyby
Cassini will attempt to bounce signals off of Saturn's moon Titan once more during a flyby on June 18, 2014, revealing important details about the moon's surface. Image credit: NASA/JPL-Caltech
› Larger view


June 17, 2014

As NASA's Cassini spacecraft zooms toward Saturn's smoggy moon Titan for a targeted flyby on June 18, mission scientists are excitedly hoping to repeat a scientific tour de force that will provide valuable new insights into the nature of the moon's surface and atmosphere.

For Cassini's radio science team, the last flyby of Titan, on May 17, was one of the most scientifically valuable encounters of the spacecraft's current extended mission. The focus of that flyby, designated "T-101," was on using radio signals to explore the physical nature of Titan's vast northern seas and probe the high northern regions of its substantial atmosphere.

The Cassini team hopes to replicate the technical success of that flyby during the T-102 encounter, slated for June 18, during which the spacecraft will attempt similar measurements of Titan. During closest approach, the spacecraft will be just 2,274 miles (3,659 kilometers) above the surface of the moon while travelling at 13,000 miles per hour (5.6 kilometers per second).

During the upcoming flyby, if all goes well as before, Cassini's radio science subsystem will bounce signals off the surface of Titan, toward Earth, where they will be received by the ground stations of NASA's Deep Space Network. This sort of observation is known as a bistatic scattering experiment and its results can yield clues to help answer a variety of questions about large areas of Titan's surface: Are they solid, slushy or liquid? Are they reflective? What might they be made of?

During the May encounter, Cassini beamed radio signals over the two largest bodies of liquid on Titan, seas named Ligeia Mare and Kraken Mare. During that first attempt, scientists could not be certain the signals would successfully bounce off the lakes to be received on Earth. They were thrilled when ground stations received specular reflections -- essentially the glint -- of the radio frequencies as they ricocheted off Titan.

"We held our breath as Cassini turned to beam its radio signals at the lakes," said Essam Marouf, a member of the Cassini radio science team of San Jose State University in California. "We knew we were getting good quality data when we saw clear echoes from Titan's surface. It was thrilling."

A second technical accomplishment -- an experiment to send precision-tuned radio frequencies through Titan's atmosphere -- also makes the May and June flybys special. The experiment, known as a radio occultation, provides information about how temperatures vary by altitude in Titan's atmosphere. Preparing for these experiments tested just how thoroughly the Cassini team has come to understand the structure of Titan's atmosphere during nearly a decade of study by the mission.

During this type of radio occultation, a signal is beamed from Earth through the atmosphere of Titan toward the Cassini spacecraft, which responds back to Earth with an identical signal. Information about Titan is imprinted in the signal as it passes through the moon's atmosphere, encountering differences in temperature and density. The trick is that the transmitted signal must be varied during the experiment so that it remains nearly constant when received by the spacecraft.

In order to give the occultation experiments any chance of success, the team has to account for not only the relative motions of the spacecraft and the transmitting antennas on the rotating planet Earth, but also the ways the signal is bent by different layers in Titan's atmosphere.

While this procedure has been used successfully for several Saturn occultations in the past two years, it had not yet been tried at Titan. And since the Titan occultations last just a few minutes, the team was concerned about how quickly the frequency lockup between ground and spacecraft could be established, if at all. For comparison, NASA's Magellan mission tried the technique at Venus in the 1990s, without success.

As they waited for signs of confirmation during the May encounter, the team saw the signal lock occur in only a few seconds, indicating that their predictions were spot-on. Data on Titan's atmosphere flowed in, adding new information to the mission's campaign to monitor the changing of the seasons on this alien moon.

"This was like trying to hit a hole-in-one in golf, except that the hole is close to a billion miles away, and moving," said Earl Maize, Cassini project manager at NASA's Jet Propulsion Laboratory in Pasadena, California. "This was our first attempt to precisely predict and compensate for the effect of Titan's atmosphere on the uplinked radio signal from Earth, and it worked to perfection."

The Cassini-Huygens mission is a cooperative project of NASA, the European Space Agency and the Italian Space Agency. JPL, a division of the California Institute of Technology, Pasadena, manages the mission for NASA's Science Mission Directorate in Washington. The radio science team is based at JPL. NASA's Deep Space Network is also managed by JPL.

More information about Cassini is available at the following sites:

http://www.nasa.gov/cassini

http://saturn.jpl.nasa.gov

Preston Dyches

Jet Propulsion Laboratory, Pasadena, Calif.

818-354-7013

preston.dyches@jpl.nasa.gov



2014-192
Posted by Nelio Inacio at 7:41 AM 0 comments

QuikScat's Eye on Ocean Winds Lives On with RapidScat

QuikScat's Eye on Ocean Winds Lives On with RapidScat:

Using data from NASA's QuikScat, weather forecasters were able to predict hazardous weather events over oceans 6 to 12 hours earlier than before these data were available
Using data from NASA's QuikScat, weather forecasters were able to predict hazardous weather events over oceans 6 to 12 hours earlier than before these data were available. Orange areas show where winds are blowing the hardest and blue shows relatively light winds. Image credit: NASA


June 19, 2014

Today (June 19) marks the 15th anniversary of the launch of NASA's QuikScat, a satellite sent for a three-year mission in 1999 that continues collecting data. Built in less than 12 months, QuikScat has watched ocean wind patterns for 15 years and improved weather forecasting worldwide. Despite a partial instrument failure in 2009, it provides calibration data to international partners.

On this anniversary, the mission's team is preparing to calibrate ISS-RapidScat, the successor that will maintain QuikScat's unbroken data record. After its launch in a few months, RapidScat will watch ocean winds from the International Space Station (ISS) for a two-year mission.

Much like QuikScat, ISS-RapidScat was built in less than two years and at a fraction of its predecessor's budget. Both missions are testaments to ingenuity, craftsmanship and speedy construction in the name of improving our understanding of Earth's winds.

"Both ISS-RapidScat and QuikScat came about to react quickly to the failure of another spaceborne instrument," said Ernesto Rodriguez, project scientist for the ISS-RapidScat mission at NASA's Jet Propulsion Laboratory, Pasadena, California. "What differentiates these missions is cost and risk: RapidScat had to be built with a fraction of the QuikScat budget, and the mission accepted a much riskier approach," Rodriguez said. RapidScat was constructed primarily from QuikScat's spare parts and will be the first scatterometer to berth on the International Space Station.

Scatterometers help scientists estimate the speed and direction of winds at the ocean's surface by sending microwave pulses to Earth's surface. Strong waves or ripples scatter the microwaves, sending some of them back toward the scatterometer. Based on the strength of this backscatter, scientists can estimate the strength and direction of the wind at the ocean's surface.

Scatterometer data are critical for observing global weather patterns. They also help ocean fishermen decide where to fish, ship captains choose shipping lanes and researchers track hurricanes, cyclones and El Niños.

"The usefulness of this wind measurement is enormous," said JPL's Jim Graf, who served as project manager for the QuikScat mission in the 1990s and is now the deputy director of JPL's Earth Science and Technology Directorate. "One of the dominant factors in understanding the climate is to assess what is happening in the ocean circulation. And one of the dominant factors in ocean circulation is the wind at the surface, which is what scatterometers measure."

NASA launched its first scatterometer satellite in 1978 and its second instrument, the NASA Scatterometer (NSCAT), on a Japanese satellite in 1996. Each lasted less than a year, but collected hundreds of times more data about ocean winds than ships or buoys and improved weather forecasts from the National Oceanic and Atmospheric Administration (NOAA).

But the spacecraft carrying NSCAT malfunctioned in 1997. Immediately, a team of JPL scientists and engineers raced to get a scatterometer satellite back into space.

"We had the idea that a partially developed spacecraft bus could be mated with an advanced version of the instrument that was already under development, and we could get something up quickly. So we went to NASA, and they said, 'Okay, let's give it a shot, but we want you to be ready to go one year from the go-ahead,'" Graf said. "And so we took off running, and we didn't stop for a whole year."

In that year, Ball Aerospace & Technologies Corp., Boulder, Colorado, built the QuikScat satellite bus while JPL finished the new SeaWinds scatterometer instrument. It launched in 1999. For the next decade, QuikScat made about 400,000 daily measurements of wind speed and direction. Over 15-mile (25-kilometer) segments of ocean, its measurements were detailed enough to estimate average wind speed within 6 feet (2 meters) per second.

The SeaWinds instrument on QuikScat used a rotating antenna to measure a swath of Earth's surface 1,118 miles (1,800 kilometers) wide -- about the distance from Los Angeles to Seattle. As QuikScat flew, the rotations overlapped to cover more than 90 percent of Earth's surface every day.

But by the end of 2009, long after the expected end of QuikScat's mission, the lubricant coating the antenna's bearings dried up. Instead of tracing a round swath on Earth's surface, it pointed straight down and only watched the waves directly below it. Still, those data were sufficient to help calibrate newer satellites.

"Since 2009, we've been able to keep QuikScat operating quite successfully," said QuikScat Project Manager Rob Gaston of JPL. "We used QuikScat's highly successful backscatter measurements, which were well understood and had demonstrated stability, as a calibration standard for many instruments, including other scatterometers." The European Space Agency and Indian Space Research Organization have both used QuikScat data to calibrate scatterometers in the last five years.

QuikScat's final task will be to calibrate its successor, RapidScat. The satellite will continue collecting data until April 2015, when it will be decommissioned after nearly 16 years in orbit.

RapidScat, like QuikScat, was built in a fraction of the timeline for most missions. The two missions even share hardware: JPL engineers used SeaWinds test parts to build much of RapidScat, which also uses a rotating dish antenna.

RapidScat will launch aboard a SpaceX Dragon resupply mission this summer. Flying in the space station's orbit means RapidScat will spend more time observing Earth's tropics than previous scatterometer satellites, which orbited farther north and south.

"RapidScat will be able to, for the first time, map the evolution of winds as the day progresses, which is important for understanding how clouds and precipitation develop, especially in the tropics, which are key regions in Earth's climate system," Rodriguez said. "It will provide a common reference to tie all of these measurements together."

Together with scatterometers managed by India and Europe, RapidScat will maintain the continuous climate record QuikScat began while adding its own unique perspective from orbit.

For more information about ISS-RapidScat, visit:

http://winds.jpl.nasa.gov/missions/RapidScat/

For more information about QuikScat, visit:

http://winds.jpl.nasa.gov/missions/quikscat/

NASA monitors Earth's vital signs from land, air and space with a fleet of satellites and ambitious airborne and ground-based observation campaigns. NASA develops new ways to observe and study Earth's interconnected natural systems with long-term data records and computer analysis tools to better see how our planet is changing. The agency shares this unique knowledge with the global community and works with institutions in the United States and around the world that contribute to understanding and protecting our home planet.

For more information about NASA's Earth science activities in 2014, visit:

http://www.nasa.gov/earthrightnow

Alan Buis

818-354-0474

Jet Propulsion Laboratory, Pasadena, Calif.

Alan.Buis@jpl.nasa.gov


Written by Rosalie Murphy

JPL Earth Science and Technology Directorate


#2014-194
Posted by Nelio Inacio at 7:39 AM 0 comments

Titan's Building Blocks Might Pre-date Saturn

Titan's Building Blocks Might Pre-date Saturn:

Titan
New research on the nitrogen in Titan's atmosphere indicates that the moon's raw materials might have been locked up in ices that condensed before Saturn began its formation.
Image Credit: NASA/JPL-Caltech/Space Science Institute
› Full image and caption


June 23, 2014

A combined NASA and European Space Agency (ESA)-funded study has found firm evidence that nitrogen in the atmosphere of Saturn's moon Titan originated in conditions similar to the cold birthplace of the most ancient comets from the Oort cloud. The finding rules out the possibility that Titan's building blocks formed within the warm disk of material thought to have surrounded the infant planet Saturn during its formation.

The main implication of this new research is that Titan's building blocks formed early in the solar system's history, in the cold disk of gas and dust that formed the sun. This was also the birthplace of many comets, which retain a primitive, or largely unchanged, composition today.

The research, led by Kathleen Mandt of Southwest Research Institute in San Antonio, and including an international team of researchers, was published this week in the Astrophysical Journal Letters.

Nitrogen is the main ingredient in the atmosphere of Earth, as well as on Titan. The planet-sized moon of Saturn is frequently compared to an early version of Earth, locked in a deep freeze.

The paper suggests that information about Titan's original building blocks is still present in the icy moon's atmosphere, allowing researchers to test different ideas about how the moon might have formed. Mandt and colleagues demonstrate that a particular chemical hint as to the origin of Titan's nitrogen should be essentially the same today as when this moon formed, up to 4.6 billion years ago. That hint is the ratio of one isotope, or form, of nitrogen, called nitrogen-14, to another isotope, called nitrogen-15.

The team finds that our solar system is not old enough for this nitrogen isotope ratio to have changed significantly. This is contrary to what scientists commonly have assumed.

"When we looked closely at how this ratio could evolve with time, we found that it was impossible for it to change significantly. Titan's atmosphere contains so much nitrogen that no process can significantly modify this tracer even given more than four billion years of solar system history," Mandt said.

The small amount of change in this isotope ratio over long time periods makes it possible for researchers to compare Titan's original building blocks to other solar system objects in search of connections between them.

As planetary scientists investigate the mystery of how the solar system formed, isotope ratios are one of the most valuable types of clues they are able to collect. In planetary atmospheres and surface materials, the specific amount of one form of an element, like nitrogen, relative to another form of that same element can be a powerful diagnostic tool because it is closely tied to the conditions under which materials form.

The study also has implications for Earth. It supports the emerging view that ammonia ice from comets is not likely to be the primary source of Earth's nitrogen. In the past, researchers assumed a connection between comets, Titan and Earth, and supposed the nitrogen isotope ratio in Titan's original atmosphere was the same as that ratio is on Earth today. Measurements of the nitrogen isotope ratio at Titan by several instruments of the NASA and ESA Cassini-Huygens mission showed that this is not the case -- meaning this ratio is different on Titan and Earth -- while measurements of the ratio in comets have borne out their connection to Titan. This means the sources of Earth's and Titan's nitrogen must have been different.

Other researchers previously had shown that Earth's nitrogen isotope ratio likely has not changed significantly since our planet formed.

"Some have suggested that meteorites brought nitrogen to Earth, or that nitrogen was captured directly from the disk of gas that formed the sun. This is an interesting puzzle for future investigations," Mandt said.

Mandt and colleagues are eager to see whether their findings are supported by data from ESA's Rosetta mission, when it studies comet 67P/ Churyumov-Gerasimenko beginning later this year. If their analysis is correct, the comet should have a lower ratio of two isotopes -- in this case of hydrogen in methane ice -- than the ratio on Titan. In essence, they believe this chemical ratio on Titan is more similar to Oort cloud comets than comets born in the Kuiper Belt, which begins near the orbit of Neptune (67P/ Churyumov-Gerasimenko is a Kuiper Belt comet).

"This exciting result is a key example of Cassini science informing our knowledge of the history of solar system and how the Earth formed," said Scott Edgington, Cassini deputy project scientist at NASA's Jet Propulsion Laboratory, Pasadena, California.

The Cassini-Huygens mission is a cooperative project of NASA, ESA and the Italian Space Agency. JPL, a division of the California Institute of Technology, Pasadena, manages the mission for NASA's Science Mission Directorate in Washington.

Rosetta is an ESA mission with contributions from its member states and NASA. JPL manages the U.S. contribution of the Rosetta mission for NASA's Science Mission Directorate in Washington.

More information about Cassini is available at the following sites:

http://www.nasa.gov/cassini

http://saturn.jpl.nasa.gov

Preston Dyches/Whitney Clavin

NASA's Jet Propulsion Laboratory, Pasadena, Calif.

818-354-7013/818-354-4673

preston.dyches@jpl.nasa.gov/whitney.clavin@jpl.nasa.gov


2014-200
Posted by Nelio Inacio at 7:39 AM 0 comments

NASA Low-Density Supersonic Decelerator Set to Lift Off

NASA Low-Density Supersonic Decelerator Set to Lift Off:

This artist's concept shows the test vehicle for NASA's Low-Density Supersonic Decelerator (LDSD), designed to test landing technologies for future Mars missions.
This artist's concept shows the test vehicle for NASA's Low-Density Supersonic Decelerator (LDSD), designed to test landing technologies for future Mars missions. Image credit: NASA/JPL-Caltech
› Full image and caption


June 27, 2014

Mission managers are proceeding with preparations for a launch attempt tomorrow morning, Saturday, June 28, of a high-altitude balloon carrying the Low-Density Supersonic Decelerator (LDSD) test vehicle to the edge of space. The text will occur at the U.S. Navy's Pacific Missile Range Facility in Kauai, Hawaii.

At present, weather forecasted for tomorrow morning is within launch constraints. Mission managers will evaluate latest weather conditions later this evening to confirm favorable conditions.

The Saturday balloon launch window extends from approximately 11:15 a.m. to noon PDT (8:15 a.m. to 9 a.m. HST). The balloon will take approximately 2 to 3 hours to achieve float conditions. Shortly thereafter, the test vehicle will be released from the balloon and the test will begin.

Check back here and on our Twitter sites: @NASA_Technology, @NASA, @NASAJPL and @NASA_Marshall to get the latest updates on the mission.

NASA will stream live video of the test via Ustream at:

http://www.ustream.tv/nasajpl2

The video may be intermittent based on test activities. For real-time updates, and more information, reporters should consult:

http://go.usa.gov/kzZQ

NASA plans on providing edited supporting video of the test the day after flight.

For NASA TV streaming video, schedules and downlink information, visit:

http://www.nasa.gov/nasatv

NASA's LDSD program is part of the agency's Space Technology Mission Directorate, which is innovating, developing, testing and flying hardware for use in NASA's future missions.

DC Agle/Whitney Clavin
Jet Propulsion Laboratory, Pasadena, Calif.
818-393-9011/818-354-4673
agle@jpl.nasa.gov/whitney.clavin@jpl.nasa.gov

David Steitz
NASA Headquarters, Washington

202-236-5829

david.steitz@nasa.gov

Stefan Alford

Pacific Missile Range Facility, Kauai, Hawaii

808-335-4740

stefan.alford@navy.mil

2014-207
Posted by Nelio Inacio at 7:37 AM 0 comments

Rosetta's Comet Target 'Releases' Plentiful Water

Rosetta's Comet Target 'Releases' Plentiful Water:

This artist's impression shows the Rosetta orbiter at comet 67P/Churyumov-Gerasimenko.
This artist's impression shows the Rosetta orbiter at comet 67P/Churyumov-Gerasimenko. The image is not to scale. Image Credit: ESA/ATG Medialab
› Full image and caption


June 30, 2014

Comet 67P/Churyumov-Gerasimenko is releasing the Earthly equivalent of two glasses of water into space every second. The observations were made by the Microwave Instrument for Rosetta Orbiter (MIRO), aboard the European Space Agency's Rosetta spacecraft on June 6, 2014. The detection of water vapor has implications not only for cometary science, but also for mission planning, as the Rosetta team prepares the spacecraft to become the first ever to orbit a comet (planned for August), and the first to deploy a lander to its surface (planned for November 11).

"We always knew we would see water vapor outgassing from the comet, but we were surprised at how early we detected it," said Sam Gulkis, principal investigator of the MIRO instrument at NASA's Jet Propulsion Laboratory in Pasadena, California. "At this production rate, comet 67P/Churyumov-Gerasimenko would fill an Olympic-size swimming pool in about 100 days. But, as the comet gets closer to the sun, the gas production rate will increase. With Rosetta, we have an amazing vantage point to observe these changes up close and learn more about exactly why they happen."

MIRO first detected water vapor from the comet when the Rosetta spacecraft was about 217,000 miles (350,000 kilometers) away from it. At the time, comet 67P/Churyumov-Gerasimenko was 363 million miles (583 million kilometers) from the sun. After the initial June 6 discovery, water vapor was also detected every time the MIRO instrument was pointed toward the comet. Observations are continuing to monitor variability in the production rate, and to determine the global gas production rate, as a function of its distance from the sun. The gas production rate that MIRO determined provides scientists a measure of the evolution of the comet as it moves both toward, and then away, from the sun. The gas production rate is also important to the Rosetta navigation team controlling the spacecraft, as this flowing gas can alter the trajectory of spacecraft.

"Our comet is coming out of its deep-space slumber and beginning to put on a show for Rosetta's science instruments," said Matt Taylor, Rosetta's project scientist from the European Space Agency's Science and Technology Centre in Noordwijk, The Netherlands. "The mission's engineers will be using this MIRO data to help them plan for future mission events when we are operating in close proximity to the comet's nucleus."

Rosetta is currently about halfway between Mars and Jupiter, 261 million miles (420 million kilometers) from Earth and 354 million miles (569 million kilometers) from the sun. Comets are time capsules containing primitive material left over from the epoch when the sun and its planets formed. By studying the gas, dust and structure of the nucleus and organic materials associated with the comet, via both remote and in-situ observations, the Rosetta mission should be a key to unlocking the history and evolution of our solar system, as well as answering questions regarding the origin of Earth's water and perhaps even life. Rosetta will be the first mission in history to rendezvous with a comet, escort it as it orbits the sun, and deploy a lander to its surface.

MIRO is a small and lightweight spectrometer instrument, the first of its kind launched into deep space. The MIRO science team is composed of 22 scientists from the United States, France, Germany and Taiwan. Resembling a miniaturized ground-based radio telescope, it was designed to study the composition, velocity and temperature of gases on or near the comet's surface and measure the temperature of the nucleus down to a depth of several inches, or centimeters. Studying the nucleus temperature and evolution of the coma and tail provides information on how the comet evolves as it approaches and leaves the vicinity of the sun, and addresses questions about why that happens. During Rosetta flybys of the asteroids (2867) Steins and (21) Lutetia in 2008 and 2010 respectively, the instrument measured thermal emission from these asteroids and searched for water vapor.

MIRO is one of three U.S. instruments aboard the Rosetta spacecraft. The other two are an ultraviolet spectrometer called Alice, and the Ion and Electron Sensor (IES). They are part of a suite of 11 science instruments aboard the Rosetta orbiter. NASA also provided part of the electronics package for the Double Focusing Mass Spectrometer, which is part of the Swiss-built Rosetta Orbiter Spectrometer for Ion and Neutral Analysis (ROSINA) instrument. NASA's Deep Space Network is supporting ESA's Ground Station Network for spacecraft tracking and navigation.

The Microwave Instrument for Rosetta Orbiter (MIRO) was built at JPL. Hardware subsystems for MIRO were provided by the Max-Planck Institute for Solar System Research and the Laboratoire d'Etudes du Rayonnement et de la Matiere en Astrophysique of the Observatoire de Paris. The consortium also includes the Laboratoire d'Etudes Spatiales ed d'Instrumentation en Astrophysique of the Observatoire de Paris.

Rosetta is an ESA mission with contributions from its member states and NASA. Rosetta's Philae lander is provided by a consortium led by the German Aerospace Center, Cologne; Max Planck Institute for Solar System Research, Go?ttingen; French National Space Agency, Paris; and the Italian Space Agency, Rome. JPL, a Division of the California Institute of Technology, Pasadena, manages the U.S. contribution of the Rosetta mission for NASA's Science Mission Directorate in Washington. JPL also built the MIRO and hosts its principal investigator, Samuel Gulkis. The Southwest Research Institute (San Antonio and Boulder), developed the Rosetta orbiter's IES and Alice instruments, and hosts their principal investigators, James Burch (IES) and Alan Stern (Alice).

For more information on the U.S. instruments aboard Rosetta, visit:

http://rosetta.jpl.nasa.gov

More information about Rosetta is available at:

http://www.esa.int/rosetta

For more information on the DSN, visit:

http://deepspace.jpl.nasa.gov/dsn

DC Agle

Jet Propulsion Laboratory, Pasadena, Calif.

818-393-9011

agle@jpl.nasa.gov


Dwayne Brown

Headquarters, Washington

202-358-1726

dwayne.c.brown@nasa.gov


Markus Bauer

European Space Agency, Noordwijk, Netherlands

011-31-71-565-6799

markus.bauer@esa.int


2014-212
Posted by Nelio Inacio at 7:36 AM 0 comments

Cassini Names Final Mission Phase Its 'Grand Finale'

Cassini Names Final Mission Phase Its 'Grand Finale':

With help from the public, members of NASA's Cassini mission have chosen to call the spacecraft's
With help from the public, members of NASA's Cassini mission have chosen to call the spacecraft's final orbits the "Cassini Grand Finale." Image credit: NASA/JPL-Caltech
› Larger image


June 30, 2014

With input from more than 2,000 members of the public, team members on NASA's Cassini mission to Saturn have chosen a name for the final phase of the mission: the Cassini Grand Finale.

Starting in late 2016, the Cassini spacecraft will begin a daring set of orbits that is, in some ways, like a whole new mission. The spacecraft will repeatedly climb high above Saturn's north pole, flying just outside its narrow F ring. Cassini will probe the water-rich plume of the active geysers on the planet's intriguing moon Enceladus, and then will hop the rings and dive between the planet and innermost ring 22 times.

Because the spacecraft will be in close proximity to Saturn, the team had been calling this phase "the proximal orbits," but they felt the public could help decide on a more exciting moniker. In early April, the Cassini mission invited the public to vote on a list of alternative names provided by team members or to suggest ideas of their own.

"We chose a name for this mission phase that would reflect the exciting journey ahead while acknowledging that it's a big finish for what has been a truly great show," said Earl Maize, Cassini project manager at NASA's Jet Propulsion Laboratory in Pasadena, California.

For more information about the name contest, visit:

http://saturn.jpl.nasa.gov/name

For a visualization of the Grand Finale, visit:

http://eyes.nasa.gov and click on "Cassini's Tour"

Preston Dyches

Jet Propulsion Laboratory, Pasadena, Calif.

818-354-7013

preston.dyches@jpl.nasa.gov


2014-213
Posted by Nelio Inacio at 7:35 AM 0 comments

WONDERFUL Black Hole Fireworks in Nearby Galaxy

Black Hole Fireworks in Nearby Galaxy:

A galaxy about 23 million light-years away is the site of impressive, ongoing, fireworks.
A galaxy about 23 million light-years away is the site of impressive, ongoing, fireworks. Rather than paper, powder, and fire, this galactic light show involves a giant black hole, shock waves, and vast reservoirs of gas.
Image Credit:
NASA/CXC/JPL-Caltech/STScI/NSF/NRAO/VLA
› Full image and caption


July 02, 2014

Celebrants this Fourth of July will enjoy the dazzling lights and booming shock waves from the explosions of fireworks. A similarly styled event is taking place in the galaxy Messier 106, as seen by NASA's Spitzer Space Telescope, Chandra X-ray Observatory and the Herschel Space Observatory. Herschel is a European Space Agency mission with important NASA contributions.

Energetic jets, which blast from Messier 106's central black hole, are heating up material in the galaxy and thus making it glow, like the ingredients in a firework. The jets also power shock waves that are driving gases out of the galaxy's interior.

Those gases constitute the fuel for churning out new stars. A new study estimates the shock waves have already warmed and ejected two-thirds of the gas from the center of Messier 106. With a reduced ability to birth new stars, Messier 106 appears to be transitioning into a barren, so-called lenticular galaxy full of old, red stars. Lenticular galaxies are flat disks without prominent spiral arms.

"Jets from the supermassive black hole at the center of Messier 106 are having a profound influence on the available gas for making stars in this galaxy," said Patrick Ogle, an astrophysicist at the Infrared Processing and Analysis Center at the California Institute of Technology in Pasadena, and lead author of a new paper describing the results. "This process may eventually transform the spiral galaxy Messier 106 into a lenticular galaxy, depriving it of the raw material to form stars."

Many galaxies contain a central black hole that actively "feeds" upon nearby gas. Some of the material, as it draws toward the black hole, dramatically speeds up and violently spews out as twin jets near the black hole's poles. As one of the Milky Way's closest galactic neighbors, Messier 106 offers a great opportunity for investigating these high-powered jets. Messier 106 -- also known as NGC 4258 -- is 23.5 million light-years distant, and visible with binoculars in the constellation Canes Venatici.

For the new study, researchers used data obtained with the Spitzer infrared telescope before the observatory ran out of coolant in 2009, as planned. The data amount to a map of the infrared light emitted by heated-up hydrogen molecules in Messier 106. The warmed hydrogen is a signature of the jet from the central black hole energizing the surrounding disk of the galaxy.

Specifically, Spitzer saw warmed hydrogen in the two mysterious spiral arms for which Messier 106 is famous. These arms are not like the usual, star-filled spiral arms found in spiral galaxies, such as our Milky Way. In previous research with Spitzer and Chandra, researchers discovered that twin jets from the black hole spawned the anomalous arms, which contain gas heated to millions of degrees that shines in X-rays, detected by Chandra.

In the inner portions of the anomalous spiral arms, the Spitzer infrared images have revealed the equivalent of 10 million times the mass of the sun of molecular hydrogen heated to between about minus 20 and 1,400 degrees Fahrenheit (minus 28 and 760 degrees Celsius) by the shock waves. Without the shock waves, this gas would be colder, likely a few hundred degrees below zero, Fahrenheit.

From a direct comparison of the Chandra and Spitzer images, Ogle and colleagues saw that there is a close connection between the gas that is shocked to millions of degrees, seen by Chandra, and the bulk of denser hydrogen gas heated to hundreds of degrees, seen by Spitzer. The jet is surrounded by a cocoon of superhot gas, which drives shock waves into the surrounding molecular hydrogen gas, like a firework popping off. The molecular hydrogen then heats up, emits infrared light that Spitzer records, and is cast out of the galaxy's gas-strewn interior.

The Herschel observations, meanwhile, pinned down the heat radiating from dust grains that are mixed in with the galaxy's shock-heated gas. "A relatively large amount of molecular gas emission compared to dust emission confirms that shock-driven turbulence from the black hole jets is heating the molecular gas," said paper co-author Philip Appleton of the NASA Herschel Science Center at Caltech.

Spitzer and Herschel were also able to gauge the level of star-making activity in Messier 106's central region. The little gas left there supports a paltry star-formation rate of only 0.08 solar, or sun-equivalent, masses per year (a robust pace runs to about three solar masses per year). The star-formation rate in Messier 106's inner quarters will continue to decline until the jets have ejected all of the gas from the center of the galaxy, turning Messier 106 into an over-the-hill lenticular galaxy.

"Our results demonstrate that these black hole jets can have a significant impact on the evolution of their host galaxies, eventually sterilizing them and making them bereft of the gas needed to form new stars," said Ogle.

NASA's Jet Propulsion Laboratory, Pasadena, California, manages the Spitzer Space Telescope mission for NASA's Science Mission Directorate, Washington. In 2009, the telescope began its "warm" mission, which takes advantage of the still-working, shortest-wavelength infrared channels on the observatory. Science operations are conducted at the Spitzer Science Center at Caltech. Spacecraft operations are based at Lockheed Martin Space Systems Company, Littleton, Colorado. Data are archived at the Infrared Science Archive housed at the Infrared Processing and Analysis Center at Caltech. Caltech manages JPL for NASA.

Herschel is a European Space Agency mission, with science instruments provided by consortia of European institutes and with important participation by NASA. While the observatory stopped making science observations in April 2013, after running out of liquid coolant, as expected, scientists continue to analyze its data. NASA's Herschel Project Office is based at JPL. JPL contributed mission-enabling technology for two of Herschel's three science instruments. The NASA Herschel Science Center, part of the Infrared Processing and Analysis Center at Caltech, supports the U.S. astronomical community. Caltech manages JPL for NASA.

NASA's Marshall Space Flight Center in Huntsville, Ala., manages the Chandra program for NASA's Science Mission Directorate in Washington. The Smithsonian Astrophysical Observatory in Cambridge, Mass., controls Chandra's science and flight operations.

More information is online at:

http://spitzer.caltech.edu

http://www.herschel.caltech.edu

http://www.chandra.harvard.edu

Whitney Clavin 818-354-4673

Jet Propulsion Laboratory, Pasadena, Calif.

whitney.clavin@jpl.nasa.gov


2014-216
Posted by Nelio Inacio at 7:32 AM 0 comments

Ocean on Saturn Moon Could be as Salty as the Dead Sea

Ocean on Saturn Moon Could be as Salty as the Dead Sea:

Researchers found that Titan's ice shell, which overlies a very salty ocean
Researchers found that Titan's ice shell, which overlies a very salty ocean, varies in thickness around the moon, suggesting the crust is in the process of becoming rigid. Image credit: NASA/JPL -Caltech/SSI/Univ. of Arizona/G. Mitri/University of Nantes
› Larger image


July 02, 2014

Scientists analyzing data from NASA's Cassini mission have firm evidence the ocean inside Saturn's largest moon, Titan, might be as salty as Earth's Dead Sea.

The new results come from a study of gravity and topography data collected during Cassini's repeated flybys of Titan during the past 10 years. Using the Cassini data, researchers presented a model structure for Titan, resulting in an improved understanding of the structure of the moon's outer ice shell. The findings are published in this week's edition of the journal Icarus.

"Titan continues to prove itself as an endlessly fascinating world, and with our long-lived Cassini spacecraft, we're unlocking new mysteries as fast as we solve old ones," said Linda Spilker, Cassini project scientist at NASA's Jet Propulsion Laboratory in Pasadena, California, who was not involved in the study.

Additional findings support previous indications the moon's icy shell is rigid and in the process of freezing solid. Researchers found that a relatively high density was required for Titan's ocean in order to explain the gravity data. This indicates the ocean is probably an extremely salty brine of water mixed with dissolved salts likely composed of sulfur, sodium and potassium. The density indicated for this brine would give the ocean a salt content roughly equal to the saltiest bodies of water on Earth.

"This is an extremely salty ocean by Earth standards," said the paper's lead author, Giuseppe Mitri of the University of Nantes in France. "Knowing this may change the way we view this ocean as a possible abode for present-day life, but conditions might have been very different there in the past."

Cassini data also indicate the thickness of Titan's ice crust varies slightly from place to place. The researchers said this can best be explained if the moon's outer shell is stiff, as would be the case if the ocean were slowly crystalizing and turning to ice. Otherwise, the moon's shape would tend to even itself out over time, like warm candle wax. This freezing process would have important implications for the habitability of Titan's ocean, as it would limit the ability of materials to exchange between the surface and the ocean.

A further consequence of a rigid ice shell, according to the study, is any outgassing of methane into Titan's atmosphere must happen at scattered "hot spots" -- like the hot spot on Earth that gave rise to the Hawaiian Island chain. Titan's methane does not appear to result from convection or plate tectonics recycling its ice shell.

How methane gets into the moon's atmosphere has long been of great interest to researchers, as molecules of this gas are broken apart by sunlight on short geological timescales. Titan's present atmosphere contains about five percent methane. This means some process, thought to be geological in nature, must be replenishing the gas. The study indicates that whatever process is responsible, the restoration of Titan's methane is localized and intermittent.

"Our work suggests looking for signs of methane outgassing will be difficult with Cassini, and may require a future mission that can find localized methane sources," said Jonathan Lunine, a scientist on the Cassini mission at Cornell University, Ithaca, New York, and one of the paper's co-authors. "As on Mars, this is a challenging task."

The Cassini-Huygens mission is a cooperative project of NASA, the European Space Agency and the Italian Space Agency. JPL manages the mission for NASA's Science Mission Directorate in Washington.

For more information about Cassini, visit

http://www.nasa.gov/cassini

and

http://saturn.jpl.nasa.gov

Preston Dyches

Jet Propulsion Laboratory, Pasadena, Calif.

818-354-7013

preston.dyches@jpl.nasa.gov


Dwayne Brown

Headquarters, Washington

202-354-1726

dwayne.c.brown@nasa.gov


2014-211
Posted by Nelio Inacio at 7:31 AM 0 comments

Comet Pan-STARRS Marches Across the Sky

Comet Pan-STARRS Marches Across the Sky:

Comet Pan-STARRS Sails By Distant Galaxy
NASA's NEOWISE mission captured a series of infrared images of comet C/2012 K1 -- also referred to as comet Pan-STARRS -- as it swept across our skies in May 2014.
› Full image and caption


July 03, 2014

NASA's NEOWISE mission captured a series of pictures of comet C/2012 K1 -- also known as comet Pan-STARRS -- as it swept across our skies in May 2014.

The comet is named after the astronomical survey project called the Panoramic Survey Telescope and Rapid Response System in Hawaii, which discovered the icy visitor in May 2012.

Comet Pan-STARRS hails from the outer fringes of our solar system, from a vast and distant reservoir of comets called the Oort cloud.

The comet is relatively close to us -- it was only about 143 million miles (230 million kilometers) from Earth when this picture was taken. It is seen passing a much more distant spiral galaxy, called NGC 3726, which is about 55 million light-years from Earth, or 2 trillion times farther away than the comet.

Two tails can be seen lagging behind the head of the comet. The bigger tail is easy to see and is comprised of gas and smaller particles. A fainter, more southern tail, which is hard to spot in this image, may be comprised of larger, more dispersed grains of dust.

Comet Pan-STARRS is on its way around the sun, with its closest approach to the sun occurring in late August. It was visible to viewers in the northern hemisphere through most of June. In the fall, after the comet swings back around the sun, it may be visible to southern hemisphere viewers using small telescopes.

The image was made from data collected by the two infrared channels on board the NEOWISE spacecraft, with the longer-wavelength channel (centered at 4.5 microns) mapped to red and the shorter-wavelength channel (3.4 microns) mapped to cyan. The comet appears brighter in the longer wavelength band, suggesting that the comet may be producing significant quantities of carbon monoxide or carbon dioxide.

Originally called the Wide-field Infrared Survey Explorer (WISE), the NEOWISE spacecraft was put into hibernation in 2011 after its primary mission was completed. In September 2013, it was reactivated, renamed NEOWISE and assigned a new mission to assist NASA's efforts to identify the population of potentially hazardous near-Earth objects. NEOWISE is also characterizing previously known asteroids and comets to better understand their sizes and compositions.

NASA's Jet Propulsion Laboratory, Pasadena, California, manages the NEOWISE mission for NASA's Near-Earth Object Observation Program of its Planetary Science Division in Washington. The Space Dynamics Laboratory in Logan, Utah, built the science instrument. Ball Aerospace & Technologies Corp. of Boulder, Colorado, built the spacecraft. Science operations and data processing take place at the Infrared Processing and Analysis Center at the California Institute of Technology in Pasadena. Caltech manages JPL for NASA.

More information on NEOWISE is online at:

http://www.nasa.gov/wise

http://www.jpl.nasa.gov/wise/

Whitney Clavin

Jet Propulsion Laboratory, Pasadena, Calif.

818-354-4673

whitney.clavin@jpl.nasa.gov


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Posted by Nelio Inacio at 7:31 AM 0 comments
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