Wednesday, August 6, 2014

Into The Black? Maybe Radio Bursts Are From Outside The Galaxy After All, Study Says

Into The Black? Maybe Radio Bursts Are From Outside The Galaxy After All, Study Says:



Image of the sky where the radio burst FRB 121102 was found, in the constellation Auriga. You can see its location with a green circle. At left is supernova remnant S147 and at right, a star formation area called IC 410. Credit: Rogelio Bernal Andreo (DeepSkyColors.com)

Image of the sky where the radio burst FRB 121102 was found, in the constellation Auriga. You can see its location with a green circle. At left is supernova remnant S147 and at right, a star formation area called IC 410. Credit: Rogelio Bernal Andreo (DeepSkyColors.com)
Where are these radio bursts coming from? Astronomers have heard these signals from the sky several times, but always with the same telescope (Parkes Observatory in Australia). There was debate about whether these were coming from inside or outside the galaxy, or even from Earth itself (given only the one observatory was detecting them.)

A new study with a different telescope, the Arecibo Observatory in Puerto Rico, concludes that the bursts are from outside the galaxy. This is the first time one of these bursts have been found in the northern hemisphere of the sky.

“Our result is important because it eliminates any doubt that these radio bursts are truly of cosmic origin,” stated Victoria Kaspi, an astrophysics researcher at McGill University who participated in the research. “The radio waves show every sign of having come from far outside our galaxy – a really exciting prospect.”

Fast radio bursts are a flurry of radio waves that last a few thousandths of a second, and at any given minute there are only seven of these in the sky on average, according to the Max Planck Institute for Radio Astronomy. Their cause is unknown. They could be anything from black holes, to neutron stars coming together, to the magnetic field of pulsars (a type of neutron star) flaring up — or something else.

Arecibo Observatory in Puerto Rico. Credit: NAIC - Arecibo Observatory, a facility of the NSF

Arecibo Observatory in Puerto Rico. Credit: NAIC – Arecibo Observatory, a facility of the NSF
The pulse was found Nov. 2, 2012 in the constellation Auriga. Astronomers believe it is from quite far away from measuring its plasma dispersion, or the slowdown of radio waves as they crash into interstellar electrons. This particular source had triple the maximum dispersion than what would be found inside the galaxy, astronomers stated.

“The brightness and duration of this event, and the inferred rate at which these bursts occur, are all consistent with the properties of the bursts previously detected by the Parkes telescope in Australia,” stated Laura Spitler, who led the research. (She was at Cornell University when the study began, but is now at the Max Planck Institute for Radio Astronomy in Bonn, Germany.)

But other research has been back-and-forth on whether these are actually extragalactic bursts. One 2013 paper supposed it could be colliding neutron stars from far away, while another said it could instead be nearby stars flaring up.

The research was published in the Astrophysical Journal and is also available in preprint version on Arxiv.

Source: McGill University and the Max Planck Institute for Radio Astronomy

Tagged as:
arecibo observatory,
fast radio burst,
radio burst
Posted by Nelio Inacio at 8:27 AM 0 comments

Your Weekend ‘SuperMoon’ Photos from Around the World

Your Weekend ‘SuperMoon’ Photos from Around the World:



The big proxigean full Moon rises over Daganzo de Arriba, near Madrid, Spain on July 12, 2014. Credit and copyright: Alvaro Ibañez Perez.

The big proxigean full Moon rises over Daganzo de Arriba, near Madrid, Spain on July 12, 2014. Credit and copyright: Alvaro Ibañez Perez.
Did you hear there was something special about the full Moon this weekend… that it would be, well… really super? I heard about it on every newscast I watched or listened to. Even xkcd got into the ‘Supermoon’ craze. The July “Buck” Moon was the first of three Supermoons on tap for 2014, where the Moon is at its perigee, the closest point to Earth in its orbit, close to the time when it is “officially” full.

If you didn’t hear about it, (or weren’t paying attention) you may not have noticed anything different, as its not radically different from a regular full Moon. Read all the detail of what a Supermoon is here. But as Geoff Chester of the US Naval Observatory, said on NASA’s website, “However, if it gets people out and looking at the night sky and maybe hooks them into astronomy, then it’s a good thing,”

And people were out with their cameras, too! Here’s a great collection of full Moon images from this weekend, as seen in our Flickr Gallery.

An over-exposed beauty showing the full Moon rising through the clouds on July 12, 2014 near Bromsgrove, England, United Kingdom. Credit and copyright: Sarah and Simon Fisher.

An over-exposed beauty showing the full Moon rising through the clouds on July 12, 2014 near Bromsgrove, England, United Kingdom. Credit and copyright: Sarah and Simon Fisher.
The rising "super moon" of July 12, 2014, rising above a canola field in southern Alberta, Canada. Credit and copyright: Alan Dyer/Amazing Sky Photography.

The rising “super moon” of July 12, 2014, rising above a canola field in southern Alberta, Canada. Credit and copyright: Alan Dyer/Amazing Sky Photography.
A Mississippi Super Moonscape on July 12, 2014. Credit and Copyright: Veronica M Photography.

A Mississippi Super Moonscape on July 12, 2014. Credit and Copyright: Veronica M Photography.
The 'Supermoon' setting on the morning of July 13, 2014 at around 6 am local time near Kapiolani, Honolulu, Hawaii. Credit and copyright: Henry Weiland.

The ‘Supermoon’ setting on the morning of July 13, 2014 at around 6 am local time near Kapiolani, Honolulu, Hawaii. Credit and copyright: Henry Weiland.
A 3-exoposure of the full Moon on July 12, 2014, taken near Cap-Rouge, Quebec City, Quebec, Canada. Credit and copyright: Denis Marquis.

A 3-exoposure of the full Moon on July 12, 2014, taken near Cap-Rouge, Quebec City, Quebec, Canada. Credit and copyright: Denis Marquis.
The July 12, 2014 Supermoon or perigee full moon shares the night sky with fireworks from a display in Chester, New York. Credit and copyright: Tom Bushey.

The July 12, 2014 Supermoon or perigee full moon shares the night sky with fireworks from a display in Chester, New York. Credit and copyright: Tom Bushey.
Moonrise with a flyby. July 13, 2014 from the UK. Credit and copyright: SculptorLil on Flickr.

Moonrise with a flyby. July 13, 2014 from the UK. Credit and copyright: SculptorLil on Flickr.
The rising waning Moon on July 13, 2014, from near Bedfordshire, UK. Credit and copyright: DawnSunrise on Flickr.

The rising waning Moon on July 13, 2014, from near Bedfordshire, UK. Credit and copyright: DawnSunrise on Flickr.
Thanks to everyone who submitted images! Check out even more great images in Universe Today’s Flickr Group!



Be advised that this month’s big full Moon was not the closest of the year. The closest Full Moon of 2014 occurs next month on August 10th at 18:11 Universal Time (UT) or 1:44 PM EDT. On that date, the Moon reaches perigee or its closest approach to the Earth at 356,896 kilometres distant at 17:44, less than an hour from Full.

Tagged as:
Moon,
Supermoon,
supermoon 2014
Posted by Nelio Inacio at 8:26 AM 0 comments

A Stunning Image of our Home Star

A Stunning Image of our Home Star:



Sunspots and a detached prominence photographed on July 11, 2014. (© Alan Friedman, All Rights Reserved.)

Sunspots and a detached prominence photographed on July 11, 2014. (© Alan Friedman, All Rights Reserved.)
Active regions 2108 and 2109 are now passing around the limb of the Sun, but not before solar photography specialist Alan Friedman grabbed a few pictures of them on Friday!   The image above, captured by Alan from his location in Buffalo, NY, shows the two large sunspots nestled in a forest of solar spicules while a large detached prominence hovers several Earth-diameters inside the corona. A beautiful snapshot of our home star!

Captured in hydrogen-alpha wavelengths, the image above has been colored by Alan, rotated 90 degrees counterclockwise, and inverted from the original. The sunspots and standing prominence are cooler in Ha than the surrounding chromosphere and corona, and so actually photograph darker.

A view of sunspot 2109 in visible light can be seen below:

AR2109 photographed by Alan Friedman on July 11, 2014.

AR2109 photographed by Alan Friedman on July 11, 2014.
Sunspots are the result of magnetic fields rising up from deep within the Sun, preventing convection from occurring in large areas on the Sun’s surface and thereby creating relatively cooler regions we see as dark spots. They can often be many times the size of Earth and can be sources of powerful solar flares.

See these and more images by Alan on his blog here.

Images © Alan Friedman. All rights reserved.

Tagged as:
Alan Friedman,
astrophotography,
hydrogen alpha,
prominence,
Star,
sun,
sunspot
Posted by Nelio Inacio at 8:25 AM 0 comments

DARPA’s Experimental Space Plane XS-1 Starts Development

DARPA’s Experimental Space Plane XS-1 Starts Development:



Concept images for DARPA’s Experimental Spaceplane (XS-1) program. Credit: DARPA.

Concept images for DARPA’s Experimental Spaceplane (XS-1) program. Credit: DARPA.
The Defense Advanced Research Projects Agency (DARPA) is looking to develop a fully-reusable unmanned spaceplane, and they are now ready to start working their proposed Experimental Spaceplane (XS-1). The agency has put together a “special forces” of sorts in the space industry, awarding prime contracts for the first phase of development to a combination of six companies. These six are a combination of “old” and “new” space companies and are:



The Boeing Company (working with Blue Origin, LLC)

Masten Space Systems (working with XCOR Aerospace)

Northrop Grumman Corporation (working with Virgin Galactic)

“We chose performers who could prudently integrate existing and up-and-coming technologies and operations, while making XS-1 as reliable, easy-to-use and cost-effective as possible,” Jess Sponable, DARPA program manager. “We’re eager to see how their initial designs envision making spaceflight commonplace—with all the potential military, civilian and commercial benefits that capability would provide.”



Each commercial entity will be able to outline their vision of the XS-1, but DARPA wants the the spaceplane to provide aircraft-like access to space for deploying small satellites to orbit and it its development, they’d like to create technology for next-generation hypersonic vehicles, — and do it more affordably.

They envision that a reusable first stage would fly to hypersonic speeds at a suborbital altitude. Then, one or more expendable upper stages would separate and deploy a satellite into low Earth orbit (LEO). The reusable first stage would then return to earth, land and be prepared for the next flight.

Key to the development, DARPA says, are modular components, durable thermal protection systems and automatic launch, flight and recovery systems that should significantly reduce logistical needs, enabling rapid turnaround between flights.

DARPA’s key technical goals for the XS-1 include flying 10 times in 10 days, flying to Mach 10+ at least once and launching a representative small payload to orbit. The program also seeks to reduce the cost of access to space for 3,000- to 5,000-pound payloads to less than $5 million per flight.

Source: DARPA

Tagged as:
DARPA,
XS-1
Posted by Nelio Inacio at 8:24 AM 0 comments

What Created This Huge Crater In Siberia?

What Created This Huge Crater In Siberia?:



An 80-meter-wide crater recently discovered in northern Siberia (Video screenshot)

An 80-meter-wide crater recently discovered in northern Siberia (video screenshot)
What is it with Russia and explosive events of cosmic origins? The 1908 Tunguska Explosion, the Chelyabinsk bolide of February 2013, and now this: an enormous 80-meter wide crater discovered in the Yamal peninsula in northern Siberia!

To be fair, this crater is not currently thought to be from a meteorite impact but rather an eruption from below, possibly the result of a rapid release of gas trapped in what was once frozen permafrost. The Yamal region is rich in oil and natural gas, and the crater is located 30 km away from its largest gas field. Still, a team of researchers are en route to investigate the mysterious hole further.

Watch a video captured by engineer Konstantin Nikolaev during a helicopter flyover below:



In the video the Yamal crater/hole has what appear to be streams of dry material falling into it. Its depth has not yet been determined.

Bill Chappell writes on NPR’s “The Two-Way”:

“The list of possible natural explanations for the giant hole includes a meteorite strike and a gas explosion, or possibly an eruption of underground ice.”
Dark material around the inner edge of the hole seems to suggest high temperatures during its formation. But rather than the remains of a violent impact by a space rock — or the crash-landing of a UFO, as some have already speculated — this crater may be a particularly explosive result of global warming.

According to The Siberian Times:

“Anna Kurchatova from Sub-Arctic Scientific Research Centre thinks the crater was formed by a water, salt and gas mixture igniting an underground explosion, the result of global warming. She postulates that gas accumulated in ice mixed with sand beneath the surface, and that this was mixed with salt – some 10,000 years ago this area was a sea.”
The crater is thought to have formed sometime in 2012.

Read more at The Siberian Times and NPR.

Tagged as:
crater,
explosion,
global warming,
hole,
impact,
meteorite,
Siberia,
sinkhole,
Yamal
Posted by Nelio Inacio at 8:22 AM 0 comments

ISON Stopped Making Dust Just Before It Passed By The Sun And Disintegrated

ISON Stopped Making Dust Just Before It Passed By The Sun And Disintegrated:



Bright, brighter, brightest: these views of Comet ISON after its closest approach to the sun Nov. 28 show that a small part of the nucleus may have survived the comet's close encounter with the sun. Images from the Solar and Heliospheric Observatory. Credit: ESA/NASA/SOHO/GSFC

Bright, brighter, brightest: these views of Comet ISON after its closest approach to the sun Nov. 28 show that a small part of the nucleus may have survived the comet’s close encounter with the sun. Images from the Solar and Heliospheric Observatory. Credit: ESA/NASA/SOHO/GSFC
Last year’s Thanksgiving adventure for astronomers happened when Comet ISON passed within 1.2 million kilometres (750,000 miles) of the Sun. While many people were hoping the comet would stick around and produce a good show, the comet disintegrated despite a brief flare-up shortly after passing perihelion.

Scientists have just modelled the production of dust on the comet and concluded there was a “violent outburst” that happened 8.5 hours before closest approach, when the comet spewed out 11,500 tonnes (12,765 tons) of material.

“It is most likely that the final break-up of the nucleus triggered this eruption, abruptly releasing gas and dust trapped inside the nucleus,” stated Werner Curdt from the Max Planck Institute of Solar System Research, who was the lead researcher on the project. “Within a few hours the dust production stopped completely.”

Because the last few parts of the comet’s encounter were obscured by an occulting disk on the Large Angle and Spectrometric Coronagraph on the Solar and Heliospheric Observatory (SOHO), astronomers decided to model the encounter based on other data they gathered before and after.

Comet ISON captured in an image from the Solar and Heliospheric Observatory (SOHO)'s Solar Ultraviolet Measurements of Emitted Radiation (SUMER) instrument. Credit: MPS

Comet ISON captured in an image from the Solar and Heliospheric Observatory (SOHO)’s Solar Ultraviolet Measurements of Emitted Radiation (SUMER) instrument. Credit: MPS
They did have one source of data, which was another instrument called the Solar Ultraviolet Measurements of Emitted Radiation (SUMER). It’s usually used to investigate plasma activity on the sun and not faint comets, but the scientists felt it could be repurposed. T

hey switched modes on the instrument and captured the tail in far ultraviolet light, light “emitted from the solar disc and reflected by the dust particles into space,” the European Space Agency stated.

Then they compared what they saw with computer simulations, coming up with the dust estimations.

The paper is available in the journal Astronomy & Astrophysics and also in preprint version on Arxiv.

Source: European Space Agency

Tagged as:
soho,
sumer
Posted by Nelio Inacio at 8:21 AM 0 comments

Cargo Ship’s Fiery Demise Could Help Predict What Happens When The Space Station Burns Up

Cargo Ship’s Fiery Demise Could Help Predict What Happens When The Space Station Burns Up:



Artist's conception of the final Automated Transfer Vehicle (ATV), Georges Lemaître, breaking up during re-entry following a cargo run to the International Space Station. Credit: ESA–D. Ducros

Artist’s conception of the final Automated Transfer Vehicle (ATV), Georges Lemaître, breaking up during re-entry following a cargo run to the International Space Station. Credit: ESA–D. Ducros
It’s sad to think about, but there will be a day sometime when the International Space Station makes its final journey — a destructive re-entry into Earth’s atmosphere. Historically, it’s been hard to break up large pieces of space hardware safely. Pieces of the Skylab space station famously rained down in Australia, while Mir’s demise triggered warnings across its re-entry path.

The European Space Agency sees an opportunity to gather more information for this future use: closely watching what happens when the final Automated Transfer Vehicle (ATV), Georges Lemaître, goes to the International Space Station and has its planned breakup in the atmosphere following the shipment.

They plan to record its last moments using a heat-seeking camera on the inside of the spacecraft. This sort of thing has been done before with NASA and the Japanese Aerospace Exploration Agency, but this will be a first for ESA.

“The data should also hold broader value,” stated Neil Murray, who is leading the project at the European Space Agency (ESA).

“The project is proceeding under our ‘Design for Demise’ effort to design space hardware in such a way that it is less likely to survive reentry and potentially endanger the public. Design for Demise in turn is part of the agency’s clean space initiative, seeking to render the space industry more environmentally friendly in space as well as on Earth.”

The Automated Transfer Vehicle Albert Einstein burning up on Nov. 2, 2013 at 12:04 GMT over an uninhabitated part of the Pacific Ocean. This picture was snapped from the International Space Station. Credit: ESA/NASA

The Automated Transfer Vehicle Albert Einstein burning up on Nov. 2, 2013 at 12:04 GMT over an uninhabitated part of the Pacific Ocean. This picture was snapped from the International Space Station. Credit: ESA/NASA
The camera will ride inside, bolted to a rack, and transmit the last 20 seconds of its lifetime to a special Reentry Satcom capsule that is designed to survive the breakup. The data will in turn be sent to Earth using an Iridium satellite.

While the SatCom will be protected by a heatshield, the challenge will be transmitting the information through the plasma generated as it falls at 6 to 7 kilometers (3.7 to 4.3 miles) a second. The breakup will happen at 80 kilometers (50 miles) and the plasma will be there until below an altitude of about 40 kilometers (25 miles), ESA stated.

“The fall will generate high-temperature plasma around it, but signals from its omnidirectional antenna should be able to make it through any gap in the plasma to the rear,” the agency added.

Georges Lemaître is expected to launch later this month and last six months in space before re-entry.

Source: European Space Agency

Tagged as:
atv,
automated transfer vehicle,
Georges Lemaître
Posted by Nelio Inacio at 8:20 AM 0 comments

Observing Challenge: 6 White Dwarf Stars to See in Your Backyard Telescope

Observing Challenge: 6 White Dwarf Stars to See in Your Backyard Telescope:



Dazzlimg Sirius, with its white dwarf companion to the lower left. Credit: NASA, ESA, H. Bond (STScI) and M. Barstow (University of Leicester).

Dazzling Sirius, with its white dwarf companion to the lower left. Credit: NASA, ESA, H. Bond (STScI) and M. Barstow (University of Leicester).
Looking for something off beat to observe? Some examples of curious astronomical objects lie within the reach of the dedicated amateur armed with a moderate-sized backyard telescope. With a little skill and persistence, you just might be able to track down a white dwarf star.  Unlike splashy nebulae or globular clusters, a white dwarf star will just appear as a speck, a tiny dot in the field of view of your telescope’s eyepiece. But just as in the case of observing other exotic objects such as red giants and quasars, part of the thrill of tracking down these astrophysical beasties is in knowing just what it is that you’re seeing. Heck, many amateur astronomers fail to realize that any white dwarf stars are within range of their instruments and have never tracked one down.

The astrophysical nature of white dwarf stars was first uncovered in the early 20th century. Most of the early white dwarf stars discovered were companions in binary star systems and this allowed astronomers to gauge their mass by following the orbital motion of such pairs over time. Soon, astronomers realized that they were looking at something peculiar, a new type of compact but massive stellar object that stubbornly refused to be pigeon-holed along the main sequence of the freshly conceived Hertzsprung-Russell diagram.

Today, we know that white dwarf stars are the remnants of stars which have long since passed the Red Giant stage. We say that a white dwarf is a degenerate star, and no, this not a commentary on its moral state. The Chandrasekhar limit gives us an upper limit in size for a white dwarf at about 1.4 solar masses, beyond which electron degeneracy pressure can no longer act against the inward pull of gravity. Our Sun will one day become a white dwarf, over 6 billion years from now. Think of cramming the mass of our star into the volume of the Earth and you have some idea just how dense a white dwarf is: a cubic centimetre of white dwarf weighs 250 about tons, and two cup fulls of white dwarf would weigh more than a Nimitz-class aircraft carrier.

Think of a white dwarf as a cooling ember of a star long past its hydrogen fusing prime. And white dwarfs will cool down to infrared radiating black dwarfs over trillions of years, far longer than the present 13.7 billion year age of the universe. In fact, the age of white dwarfs currently observed is one on the underpinning tenets of modern Big Bang cosmology.

All amazing stuff. In any event, here is a baker’s half dozen of white dwarf stars that you can find with a telescope tonight. A more extensive list of the nearest white dwarfs to the Earth can be found on Sol Station.

The orbit of Sirius B. Wikimedia Commons image in the Public Domain.

The orbit of Sirius B. Wikimedia Commons image in the Public Domain.
Sirius B:  This is the nearest white dwarf to the Earth at 8.6 light years distant. Shining at magnitude +8.5, Sirius B would be a cinch to see, if only dazzling Sirius A — the brightest star in our sky at magnitude -1.5 — were not nearby. Sirius B orbits its primary once every 50 years and will reach a maximum separation of 11.5” from its primary in 2025, a prime time to cross it off of your life list in the coming decade. Blocking the primary just out of the field of view, or using an occulting bar eyepiece is key to finding Sirius B.

Sirius B was discovered by American telescope maker Alvan Graham Clark in 1862. The Dogon people of Mali also have some curious myths surrounding the star Sirius.

Constellation: Canis Major

Right Ascension: 6 Hours 45’

Declination: -16° 43’

The apparent orbit of Procyon B through 2039. Graphic created by the author.

The apparent orbit of Procyon B through 2039. Graphic created by the author.
Procyon B: Located 11.5 light years distant, Procyon B was discovered in 1896 by John Martin Schaeberle from the Lick observatory. Shining at magnitude +10.7, the chief difficultly with spotting this white dwarf, as with Sirius B, is that it has a companion about 10 magnitudes – that’s 10,000 times brighter – nearby just 4.3” away.

Constellation: Canis Minor

Right Ascension: 7 hours 39’

Declination: +5 13’

Credit: Starry Night Education Software.

The location of GJ 440 (HIP 57367) in the southern sky. Credit: Starry Night Education Software.
-LP145-141: Also known as GJ 440, LP145-141 is one of the best southern hemisphere white dwarf stars on the list. LP145-141 is a solitary white dwarf shining at magnitude +11.5. Located 15 light years distant, LP145-141 is thought to be a member of the nearby Wolf 219 Moving Group of stars.

Constellation: Musca

Right Ascension: 11 Hours 46’

Declination: -64° 50’

Credit: Stellarium

The location of Van Maanen’s Star in the constellation Pisces. Credit: Stellarium
-Van Maanen’s Star: Shining at magnitude +12.4 and located 14.1 light years distant, Van Maanen’s star is the closest solitary white dwarf to Earth and the best example of a white dwarf for small telescopes. Discovered by Ariaan van Maanen in 1917, Van Maanen’s Star also has a very high proper motion of 3” per year.

Constellation: Pisces

Right Ascension: 00 Hours 49’

Declination: 05° 23’

Image by Author

The 40 Omicron Eridani system. Image by Author
-40 Omicron Eridani B: This is a great one to track down. The triple system of 40 Omicron Eridani b contains a fine example of a red and white dwarf orbiting a main sequence star. Located 16.5 light years distant and shining at magnitude +9.5, Omicron Eridani was the first white dwarf star discovered in 1783 by Sir William Herschel, although its true nature wasn’t deduced until 1910. Omicron Eridani B is currently 82” from its primary, an easy split.

Constellation: Eridanus

Right Ascension: 4 Hours 15’

Declination: 7° 39’

-Stein 2051: Rounding off the list and located just over 18 light years distant, Stein 2051 is another example of a red dwarf/white dwarf pair. Stein 2051 b shines at a similar brightest to Van Maanen’s star at magnitude +12.4.

Constellation: Camelopardalis

Right Ascension: 04 Hours 31’

Declination: +58° 59’

Let us know about your trials and triumphs in hunting down these fascinating objects!

Tagged as:
nearest white dwarfs,
procyon b,
procyon b orbit,
Sirius B,
van maanens star,
white dwarf,
white dwarfs for amatuers
Posted by Nelio Inacio at 8:20 AM 0 comments

Distant Stellar Atmospheres Shed Light on How Jupiter-like Planets Form

Distant Stellar Atmospheres Shed Light on How Jupiter-like Planets Form:



Image Credit: NASA / R. J. Hall

Jupiter’s rocky core. Image Credit: NASA / R. J. Hall
It’s likely that Jupiter-like planets’ origins root back to either the rapid collapse of a dense cloud or small rocky cores that glom together until the body is massive enough to accrete a gaseous envelope.

Although these two competing theories are both viable, astronomers have, for the first time, seen the latter “core accretion” theory in action. By studying the exoplanet’s host star they’ve shed light on the composition of the planet’s rocky core.

“Our results show that the formation of giant planets, as well as terrestrial planets like our own Earth, leaves subtle signatures in stellar atmospheres”, said lead author and PhD student Marcelo Tucci Maia from University of São Paulo, Brazil, in a press release.

Maia and colleagues pointed the 3.5-meter Canada-France-Hawaii Telescope toward the constellation Cygnus, in order to take a closer look at two Sun-like stars in the distant 16 Cyg triple-star system. Both stars, having formed together from the same gaseous disk over 10 billion years ago and having reached the same mass, are nearly solar twins.

But only one star, 16 Cygni B, hosts a giant planet. By decomposing the light from the two stars into their wavelengths and looking at the difference between the two stars, the team was able to detect signatures left from the planet formation process on 16 Cygni B.

It’s the perfect laboratory to study the formation of giant planets.

Difference in chemical composition between the stars 16 Cyg A and 16 Cyg B, versus the condensation temperature of the elements in the proto-planetary nebula. If the stars had identical chemical compositions then the difference (A-B) would be zero. The star 16 Cyg A is richer in all elements relative to star 16 Cyg B. In other words, star 16 Cyg B, the host star of a giant planet, is deficient in all chemical elements, especially in the refractory elements (those with high condensation temperatures and that form dust grains more easily), suggesting evidence of a rocky core in the giant planet 16 Cyg Bb. Credits: M. Tucci Maia, J. Meléndez, I. Ramírez.

Difference in chemical composition between the stars 16 Cyg A and 16 Cyg B, versus the condensation temperature of the elements in the proto-planetary nebula. Image Credit: M. Tucci Maia, J. Meléndez, I. Ramírez.
Maia and colleagues found that the star 16 Cygni A is enhanced in all chemical elements relative to 16 Cygni B. Hence, the metals removed from 16 Cygni B were most likely removed from the protoplanetary disk in order to form the planet.

On top of the overall deficiency in all elements, 16 Cygni B has an added deficiency in the refractory elements — those with high condensation temperatures that form dust grains more easily — such as iron, aluminum, nickel, magnesium, scandium, and silicon. This helps verify what astronomers have expected all along: rocky cores are rich in refractory elements.

The team was able to decipher that these missing elements likely created a rocky core with a mass of about 1.5 to 6 Earth masses, which is similar to the estimate of Jupiter’s core.

“16 Cyg is a remarkable system, but certainly not unique,” said coauthor Ivan Ramírez from the University of Texas. “It is special because it is nearby; however, there are many other binary stars with twin components on which this experiment could be performed. This could help us find planet-host stars in binaries in a much more straightforward manner compared to all other planet-finding techniques we have available today.”

The results were accepted for publication in The Astrophysical Journal Letters and are available online.

Tagged as:
Core Accretion,
exoplanets,
Stellar Atmospheres
Posted by Nelio Inacio at 8:19 AM 0 comments

Astrophoto: Milky Way Rising Above Spectacular Lightning Display

Astrophoto: Milky Way Rising Above Spectacular Lightning Display:



The rise of the Milky Way and a spectacular lightning display in Mersing, Malaysia on June 28, 2014. Credit and copyright: Justin Ng.

The rise of the Milky Way and a spectacular lightning display in Mersing, Malaysia on June 28, 2014. Credit and copyright: Justin Ng.
Here’s another beautiful astrophoto, courtesy of photographer Justin Ng from Singapore. He’s currently on a photography trip to Malaysia and by chance captured this absolutely stunning view.

“Knowing that the sky would clear after sunset, I led a group of photographers to this location to film a time-lapse of the rising Milky Way above a lonely boat,” Justin explained via email, “but what happened soon after we started shooting was amazing. We were treated to a spectacular lightning display for about an hour from 9:30pm onwards before the clouds caught up with the rising Milky Way and dominated the skies eventually.”

The image is a result of stacking 12 photos (11 shots of lightnings and 1 shot for everything else) from his time-lapse sequence.

We’re looking forward to seeing the timelapse!

See more images from his current trip here, and you can see more of Justin’s fantastic astrophotography at his website, on G+, Facebook and Twitter.

Want to get your astrophoto featured on Universe Today? Join our Flickr group or send us your images by email (this means you’re giving us permission to post them). Please explain what’s in the picture, when you took it, the equipment you used, etc.

Tagged as:
Astrophotos,
Justin Ng,
lightning,
milky way
Posted by Nelio Inacio at 8:19 AM 0 comments

Dwarf Galaxies That Dance? Andromeda Observations Reveal A Larger Cosmic Mystery

Dwarf Galaxies That Dance? Andromeda Observations Reveal A Larger Cosmic Mystery:



Astrophoto: Andromeda Galaxy by Fabio Bortoli

Andromeda Galaxy. Credit: Fabio Bortoli
What is up with these dwarf galaxies? A survey of thousands of galaxies using the Sloan Digital Sky Survey reveals something interesting, which was first revealed by looking at the massive Andromeda Galaxy nearby Earth: dwarf galaxies orbiting larger ones are often in disc-shaped orbits and not distributed randomly, as astronomers expected.

The finding follows on from research in 2013 that showed that 50% of Andromeda’s dwarf galaxies are in a single plane about a million light-years in diameter, but only 300,000 light-years thick. Now with the larger discovery, scientists suspect that perhaps there is a yet-to-be found process that is controlling gas flow in the cosmos.

“We were surprised to find that a large proportion of pairs of satellite galaxies have oppositely directed velocities if they are situated on opposite sides of their giant galaxy hosts,” stated lead author Neil Ibata of Lycée International in France.

“Everywhere we looked, we saw this strangely coherent coordinated motion of dwarf galaxies,” added Geraint Lewis, a University of Sydney physicist. “From this we can extrapolate that these circular planes of dancing dwarfs are universal, seen in about 50 percent of galaxies. This is a big problem that contradicts our standard cosmological models. It challenges our understanding of how the universe works, including the nature of dark matter.”

The astronomers also speculated this could show something unexpected in the laws of physics, such as motion and gravity, but added it would take far more investigation to figure that out.

The findings were published in the journal Nature.

Source: University of Sydney

Tagged as:
Andromeda Galaxy,
dwarf galaxies,
dwarf galaxy,
M31,
Sloan Digital Sky Survey
Posted by Nelio Inacio at 8:18 AM 0 comments

Astrophoto: Kaleidoscopic View of Mars

Astrophoto: Kaleidoscopic View of Mars:



8 months of Mars observations in a single image, from October 2013 ending end of June 2014. Credit and copyright: Leo Aerts.

8 months of Mars observations in a single image, from October 2013 ending end of June 2014. Credit and copyright: Leo Aerts.
Astrophotographer Leo Aerts from Belgium took advantage of the recent opposition of Mars and captured the Red Planet both “coming and going” in this montage of images taken from October 2013 to June of 2014. Mars reached opposition in April of this year, meaning it was closest to Earth, allowing for the brightest and best viewing.

Leo even shows the changing locations in the sky where Mars appeared across the months, allowing also for the apparent retrograde motion through Virgo during the months on either side of opposition.



Opposition of Mars (or any planet) means that planet and the Sun are on directly opposite sides of Earth. From our perspective on a spinning Earth, the other planet rises in the east just as the Sun sets in the west. Then, after staying up in the sky the entire night, the other planet sets in the west just as the Sun rises in the east.

Mars’ opposition happens about every 26 months. Opposition time is also a good time to send spacecraft to Mars, since our two planets are the closest, meaning less fuel (and time) will be needed to reach the planet. Hence, we’ve got two missions on their way to the Red Planet: MAVEN will arrive at Mars on September 21, 2014, and India’s Mars Orbiter Mission (MOM) will get there on September 24.

This year’s opposition was pretty close, but we’re currently on an improving trend: the next opposition in 2016 Mars will look even bigger and brighter and during the 2018 opposition, Mars will nearly be as close as it was in 2003.

Want to get your astrophoto featured on Universe Today? Join our Flickr group or send us your images by email (this means you’re giving us permission to post them). Please explain what’s in the picture, when you took it, the equipment you used, etc.

Tagged as:
Astrophotos,
Mars
Posted by Nelio Inacio at 8:17 AM 0 comments

First Exoplanet Discovered Beyond the “Snow Line”

First Exoplanet Discovered Beyond the “Snow Line”:



This artist's conception shows the Uranus-sized exoplanet Kepler-421b, which orbits an orange, type K star about 1,000 light-years from Earth. Kepler-421b is the transiting exoplanet with the longest known year, circling its star once every 704 days. It is located beyond the "snow line" – the dividing line between rocky and gaseous planets – and might have formed in place rather than migrating from a different orbit. David A. Aguilar (CfA)

This artist’s conception shows the Uranus-size exoplanet Kepler-421b, which orbits an orange, type K star about 1,000 light-years from Earth. Image Credit: David A. Aguilar (CfA)
Data from NASA’s crippled Kepler space telescope has unleashed a windfall of hot Jupiters — sizzling gas giants that circle their host star within days — and only a handful of Earth-like planets. A quick analysis might make it seem as though hot Jupiters are far more common than their smaller and more distant counterparts.

But in large surveys, astronomers have to be careful of the observational biases introduced into their data. Kepler, for example, mainly finds broiling furnace worlds close to their host stars. These are easier to spot than small exoplanets that take hundreds of days to transit.

New data, however, shows a transiting exoplanet, Kepler-421b, with the longest known year, clocking in at 704 days.

“Finding Kepler-421b was a stroke of luck,” said lead author David Kipping from the Harvard-Smithsonian Center for Astrophysics in a press release. “The farther a planet is from its star, the less likely it is to transit the star from Earth’s point of view. It has to line up just right.”

Kepler-416b's folded light curve. Image Credit:

Kepler-421b’s folded light curve. Blue points are data from the first transit observed, and red points are the second transit.  Image Credit: Kipping et al.
Kepler-421b is roughly 4 times Earth’s girth and at least 60 times Earth’s mass. It circles its host star at about 1.2 times the distance from the Earth to the Sun. But because its host star is much smaller than our Sun, this places its orbit beyond the snow line — the dividing line between rocky and gas planets.

On Earth, snow lines typically form at high elevations where falling temperatures turn atmospheric moisture to snow. Similarly, in planetary systems, snow lines are thought to form in the distant, colder reaches of the stars’ disk.

Depending on the distance from the star, however, other more exotic molecules — such as carbon dioxide, methane, and carbon monoxide — can freeze and turn to snow. This forms a frost on dust grains: the building blocks of planets and comets.

“The snow line is a crucial distance in planet formation theory. We think all gas giants must have formed beyond this distance,” said Kipping.

The fact that this gas giant is still beyond this distance, roughly 4 billion years after formation, suggests that it’s the first non-migrating gas giant in a transiting system found.

Astronomers currently think gas giants form by small rocky cores that glom together until the body is massive enough to accrete a gaseous envelope. As they grow, they migrate inward, sometimes moving as close to their host star as Mercury is to the Sun.

Kepler-421b may be the first exoplanet discovered to have formed in situ. But further observations, especially those of its atmosphere, will help shed light on its formation history. Unfortunately given its long year, it won’t transit again until February, 2016.

The research has been accepted for publication in The Astrophysical Journal and is available online.

Tagged as:
Core Accretion Model,
exoplanets,
kepler space telescope,
snow line
Posted by Nelio Inacio at 8:16 AM 0 comments

Threatened Spitzer Telescope Gets NASA Nod For Extension, Subject To Congress Funding

Threatened Spitzer Telescope Gets NASA Nod For Extension, Subject To Congress Funding:



Artist's concept of NASA's Spitzer Space Telescope surrounded by examples of exoplanets it has looked at. Credit: NASA/JPL-Caltech

Artist’s concept of NASA’s Spitzer Space Telescope surrounded by examples of exoplanets it has looked at. Credit: NASA/JPL-Caltech
After NASA recommended in May that Spitzer space telescope officials send in a revised budget or face possible termination of operations, in a turnaround, the agency’s science mission directorate has now agreed to extend the mission for another two years.

The news broke on Twitter yesterday when the NASA Spitzer account shared the news. An update posted on its website said the decision is “subject to the availability of Congressional appropriations in FY [fiscal year] 2015″, but added that there will soon be a call out for observing time in that period.

Previously, NASA informed Spitzer officials that due to “constrained budget conditions” that their initial request to extend operations past fiscal 2015 was not approved, in line with recommendations from the NASA senior astrophysics review. While the mission was not terminated at that time, officials were asked to “respond with a request for a budget augmentation to conduct continued operations with reduced operations costs.”

The mission was being reviewed at the same time as other astrophysics missions, such as the Kepler planet-hunting space telescope that was asking for (and received) a new mission that would allow it to do useful science despite two busted reaction wheels, or pointing devices. The review said Spitzer was the most expensive of the missions reviewed, and that the telescope’s abilities were “significantly reduced” after it ran out of coolant in 2009.

The bow shock of Zeta Ophiuchi, another runaway star observed by Spitzer (NASA/JPL-Caltech)

The bow shock of Zeta Ophiuchi, another runaway star observed by Spitzer (NASA/JPL-Caltech)
In an update on the Spitzer website, officials shared more details but did not say if the budget had been reformulated in response to NASA’s suggestion.

We are very happy to report that Spitzer operations have been extended by the NASA Science Mission Directorate for two more years! The letter of direction states: “The Science Mission Directorate has made the decision to extend Spitzer operations for the next two years. The Spitzer observatory is an important resource for on-going infrared observations for research programs across the Science Mission Directorate, and, subject to the availability of Congressional appropriations in FY 2015, it will be continued. Both the Astrophysics and the Planetary Science Divisions have requested observing time commitments for FY 2015, and both Divisions have committed funding to support their observations.” We are working hard to get a call for observing proposals issued by the end of July. And thank you to all the people at NASA Headquarters and in the community that have worked so hard to support science with Spitzer.
In recent months, some of Spitzer’s work has included searching for targets for NASA’s asteroid mission, helping to find the coldest brown dwarf ever discovered, and assisting in challenging views about star cluster formation.

Tagged as:
nasa senior review
Posted by Nelio Inacio at 8:16 AM 0 comments

‘Lopsided’ Ghostly Galactic Halo Has Some Starry Surprises

‘Lopsided’ Ghostly Galactic Halo Has Some Starry Surprises:



An image of Centaurus A. The halo goes across four degrees in the sky, about eight times the apparent width of the moon seen with the naked eye. The image was taken with the Digitized Sky Survey 2 (DSS2), the MPG/ESO 2.2-metre telescope, and the NASA/ESA Hubble Space Telescope’s Advanced Camera for Surveys (ACS). Credit: ESA/Hubble, NASA, Digitized Sky Survey, MPG/ESO

An image of Centaurus A. The halo goes across four degrees in the sky, about eight times the apparent width of the moon seen with the naked eye. The image was taken with the Digitized Sky Survey 2 (DSS2), the MPG/ESO 2.2-metre telescope, and the NASA/ESA Hubble Space Telescope’s Advanced Camera for Surveys (ACS). Credit: ESA/Hubble, NASA, Digitized Sky Survey, MPG/ESO
Centaurus A — that popular target for astrophotographers in the southern hemisphere — has a much wider halo than expected, astronomers revealed. Turns out the galaxy’s ghostly glow is about eight times the apparent width of the full moon in the sky. Examining this halo in more detail could reveal much about how galaxies come together, astronomers said.

It’s relatively easy for scientists to spot the halo around the Milky Way since we are a part of it, but it’s much harder to observe them in other galaxies because they are so faint. Looking at Centaurus A (10 million to 16 million light-years away) required the power of two Hubble Space Telescope instruments: the Advanced Camera for Surveys and the Wide Field Camera 3.

“Tracing this much of a galaxy’s halo gives us surprising insights into a galaxy’s formation, evolution, and composition,” stated lead author Marina Rejkuba of the European Southern Observatory in Germany. “We found more stars scattered in one direction than the other, giving the halo a lopsided shape — which we hadn’t expected.”

The Centaurus A Extreme Deep Field. (Image Courtesy of Astrophotography byRolf Oslen. Used with Permision).

The Centaurus A Extreme Deep Field. (Image Courtesy of Astrophotography byRolf Oslen. Used with Permision).
The astronomers examined a region that is about 295,000 light-years across — more than double the diameter of the Milky Way’s 120,000 light years. The stars inside the glow appeared to have abundant heavier elements, even in the fringes of the galaxy — a contrast to the much lighter hydrogen and helium that are found in the fringes of the Milky Way and nearby spiral galaxies.

It’s possible the heavier stars arose because Centaurus A merged with a spiral galaxy long ago, removing stars from the intruder and sticking in Centaurus A, the astronomers said.

“Even at these extreme distances, we still haven’t reached the edge of Centaurus A’s halo, nor have we detected the very oldest generation of stars,” stated co-author Laura Greggio of Italy’s INAF (Istituto Nzaionale de Astrofisica, or National Institute for Astrophysics).

“This aged generation is very important. The larger stars from it are responsible for manufacturing the heavy elements now found in the bulk of the galaxy’s stars. And even though the large stars are long dead, the smaller stars of the generation still live on and could tell us a great deal.”

The results are available in Astrophysical Journal Letters and in preprint version on Arxiv.

Source: Hubble European Space Agency Information Centre

Tagged as:
centaurus A
Posted by Nelio Inacio at 8:15 AM 0 comments

Cosmic Fireworks: A Supernova Feast And Google+ Hangout For Chandra’s 15th Anniversary

Cosmic Fireworks: A Supernova Feast And Google+ Hangout For Chandra’s 15th Anniversary:



A collection of images from the Chandra X-Ray Observatory marking its 15th anniversary in space. Top, from left: the crab Nebula, supernova remnant G292.0+1.8 and the Crab Nebula. At bottom, supernova remnant 3C58. Credit: NASA/CXC/SAO

A collection of supernova remnant images from the Chandra X-Ray Observatory marking its 15th anniversary in space. Top, from left: the Crab Nebula, G292.0+1.8 and the Crab Nebula. At bottom, 3C58. Credit: NASA/CXC/SAO
It’s well past the Fourth of July, but you can still easily find fireworks in the sky if you look around. The Chandra X-Ray Observatory has been doing just that for the past 15 years, revealing what the universe looks like in these longer wavelengths that are invisible to human eyes.

Just in time for the birthday, NASA released four pictures that Chandra took of supernova (star explosion) remnants it has observed over the years. The pictures stand as a symbol of what the telescope has shown us so far.

“Chandra changed the way we do astronomy. It showed that precision observation of the X-rays from cosmic sources is critical to understanding what is going on,” stated Paul Hertz, NASA’s Astrophysics Division director, in a press release. “We’re fortunate we’ve had 15 years – so far – to use Chandra to advance our understanding of stars, galaxies, black holes, dark energy, and the origin of the elements necessary for life.”

The telescope launched into space in 1999 aboard the space shuttle and currently works at an altitude as high as 86,500 miles (139,000 miles). It is named after Indian-American astrophysicist Subrahmanyan Chandrasekhar; the name “Chandra” also means “moon” or “luminous” in Sanskrit.

And there’s more to come. You can learn more about Chandra’s greatest discoveries and its future in this Google+ Hangout, which will start at 3 p.m. EDT (7 p.m. EDT) at this link.
Posted by Nelio Inacio at 8:15 AM 0 comments

Split-Personality Pulsar Switches From Radio To Gamma-Rays

Split-Personality Pulsar Switches From Radio To Gamma-Rays:





Another snapshot of our strange universe: astronomers recently caught a pulsar — a particular kind of dense star — switch off its radio beacon while powerful gamma rays brightened fivefold.

“It’s almost as if someone flipped a switch, morphing the system from a lower-energy state to a higher-energy one,” stated lead researcher Benjamin Stappers, an astrophysicist at the University of Manchester, England.

“The change appears to reflect an erratic interaction between the pulsar and its companion, one that allows us an opportunity to explore a rare transitional phase in the life of this binary.”

The binary system includes pulsar J1023+0038 and another star that has a fifth of the mass of the sun. They’re close orbiting, spinning around each other every 4.8 hours. This means the companion’s days are numbered, because the pulsar is pulling it apart.



Artist’s conception of pulsar J1023 before (top) and after the radio beacon (visible in green) disappeared. Credit:
NASA’s Goddard Space Flight Center
In NASA’s words, here is what is going on:

In J1023, the stars are close enough that a stream of gas flows from the sun-like star toward the pulsar. The pulsar’s rapid rotation and intense magnetic field are responsible for both the radio beam and its powerful pulsar wind. When the radio beam is detectable, the pulsar wind holds back the companion’s gas stream, preventing it from approaching too closely. But now and then the stream surges, pushing its way closer to the pulsar and establishing an accretion disk.

Gas in the disk becomes compressed and heated, reaching temperatures hot enough to emit X-rays. Next, material along the inner edge of the disk quickly loses orbital energy and descends toward the pulsar. When it falls to an altitude of about 50 miles (80 km), processes involved in creating the radio beam are either shut down or, more likely, obscured.

The inner edge of the disk probably fluctuates considerably at this altitude. Some of it may become accelerated outward at nearly the speed of light, forming dual particle jets firing in opposite directions — a phenomenon more typically associated with accreting black holes. Shock waves within and along the periphery of these jets are a likely source of the bright gamma-ray emission detected by Fermi.
You can read more about the research in the Astrophysical Journal or in preprint version on Arxiv.

Source: NASA

Tagged as:
binary star,
J1023+0038,
Neutron Star,
pulsar
Posted by Nelio Inacio at 8:14 AM 0 comments
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