The Sun has produced a whole bunch of solar flares this week

The Sun has produced a whole bunch of solar flares this week:

While the hurricanes popping up in the Atlantic has captured everyone’s attention, the Sun has had its own active week as well. A total of six solar flares have erupted from the same active sunspot since Monday — including the largest flare the Sun has produced in its current cycle.

Sunspots are cool, dark regions on the Sun’s surface with strong magnetic fields. These solar phenomena pop up on the Sun from time to time, sometimes relatively frequently. In fact, the Sun has a roughly 11-year sunspot cycle — the result of the its changing magnetic field. Magnetic material inside the Sun is always moving and rising to the surface, and it eventually causes the Sun’s north and south poles to flip. Because of this, the Sun alternates between...

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Hubble's Megamaser Galaxy

Hubble's Megamaser Galaxy: MCG+01-38-005 (below) is a special kind of megamaser; the galaxy’s active galactic nucleus pumps out huge amounts of energy, stimulating clouds of surrounding water.

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Cassini Conduct a Final Flyby of Titan Before Crashing into Saturn

Cassini Conduct a Final Flyby of Titan Before Crashing into Saturn:

When the Cassini spacecraft arrived around Saturn on July 1st, 2004, it became the fourth space probe to visit the system. But unlike the Pioneer 11 and Voyager 1 and 2 probes, the Cassini mission was the first to establish orbit around the planet for the sake of conducting long-term research. Since that time, the spacecraft and its accompanying probe – the Huygens lander – have revealed a startling amount about this system.

On Friday, September 15th, the Cassini mission will official end as the spacecraft descends into Saturn’s atmosphere. In part of this final maneuver, Cassini recently conducted one last distant flyby of Titan. This flyby is being referred to informally as “the goodbye kiss” by mission engineers, since it is providing the gravitational push necessary to send the spacecraft into Saturn’s upper atmosphere, where it will burn up.

In the course of this flyby, the spacecraft made its closest approach to Titan on Tuesday, September 12th, at 12:04 p.m. PDT (3:04 p.m. EDT), passing within 119,049 kilometers (73,974 mi) of the moon’s surface. The maneuver was designed to slow the probe down and lower the altitude of its orbit around the planet, which will cause it to descend into Saturn’s atmosphere in a few day’s time.

Artist’s conception of Cassini winging by Saturn’s moon Titan (right) with the planet in the background. Credit: NASA/JPL-Caltech

The flyby also served as an opportunity to collect some final pictures and data on Saturn’s largest moon, which has been a major focal point for much of the Cassini-Huygens mission. These will all be transmitted back to Earth at 18:19 PDT (21:19 EDT) when the spacecraft makes contact, and navigators will use this opportunity to confirm that Cassini is one course for its final dive.

All told, the spacecraft made hundreds of passes over Titan during its 13-year mission. These included a total of 127 precisely targeted encounters at close and 4far range (like this latest flyby). As Cassini Project Manager Earl Maize, from NASA’s Jet Propulsion Laboratory, said in a NASA press statement:

“Cassini has been in a long-term relationship with Titan, with a new rendezvous nearly every month for more than a decade. This final encounter is something of a bittersweet goodbye, but as it has done throughout the mission, Titan’s gravity is once again sending Cassini where we need it to go.”

In the course of making its many flybys, the Cassini spacecraft revealed a great deal about the composition of Titan’s atmosphere, its methane cycle (similar to Earth’s hydrological cycle) and the kinds of weather it experiences in its polar regions. The probe also provided high-resolution radar images of Titan’s surface, which included topography and images of its northern methane lakes.

Artist depiction of Huygens lander touching down on the surface of Saturn’s largest moon Titan. Credit: ESA

Cassini’s first flyby of Titan took place on July 2nd, 2004 – a day after the spacecraft’s orbital insertion – where it approached to within 339,000 km (211,000 mi) of the moon’s surface. On December 25th, 2004, Cassini released the Huygens lander into the planet’s atmosphere. The probe touched down on January 14th, 2005, taking hundreds of pictures of the moon’s surface in the process.

In November of 2016, the spacecraft began the Grand Finale phase of its mission, where it would make 22 orbits between Saturn and its rings. This phase began with a flyby of Titan that took it to the gateway of Saturn’s’ F-ring, the outermost and perhaps most active ring around Saturn. This was followed by a final close flyby of Titan on April 22nd, 2017, taking it to within 979 km (608 mi) of the moon’s surface.

Throughout its mission, Cassini also revealed some significant things about Saturn’s atmosphere, its hexagonal storms, its ring system, and its extensive system of moons. It even revealed previously-undiscovered moons, such as Methone, Pallene and Polydeuces. Last, but certainly not least, it conducted studies of Saturn’s moon Enceladus that revealed evidence of a interior ocean and plume activity around its southern polar region.

These discoveries are part of the reason why the probe will end its mission by plunging into Saturn’s atmosphere, about two days and 16 hours from now. This will cause the probe to burn up, thus preventing contamination of moons like Titan and Enceladus, where microbial life could possibly exist. Finding evidence of this life will be the main focus of future missions to the Saturn system, which are likely to launch in the next decade.

So long and best wishes, Cassini! You taught so much in the past decade and we hope to follow up on it very soon. We’ll all miss you when you go!



Further Reading: NASA

The post Cassini Conduct a Final Flyby of Titan Before Crashing into Saturn appeared first on Universe Today.

Geocolor Image of Hurricane Irma

Geocolor Image of Hurricane Irma: The NOAA satellite GOES-16 captured this geocolor image of Hurricane Irma passing the eastern end of Cuba at about 8:00 a.m. EDT, Sept. 8, 2017. Created by NOAA's partners at the Cooperative Institute for Research in the Atmosphere, the experimental imagery enhancement displays geostationary satellite data in different ways for day or night.

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So Far from Home

So Far from Home: With this view, Cassini captured one of its last looks at Saturn and its main rings from a distance.

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The Heart Nebula in Hydrogen, Oxygen, and Sulfur

The Heart Nebula in Hydrogen, Oxygen, and Sulfur:

Discover the cosmos! Each day a different image or photograph of our fascinating universe is featured, along with a brief explanation written by a professional astronomer.

2017 August 27

The Heart Nebula in Hydrogen, Oxygen, and Sulfur

Image Credit & Copyright: Peter Jenkins


Explanation: What powers the Heart Nebula? The large emission nebula dubbed IC 1805 looks, in whole, like a heart. The nebula's glow -- as well as the shape of the gas and dust clouds -- is powered by by stellar winds and radiation from massive hot stars in the nebula's newborn star cluster Melotte 15. This deep telescopic image maps the pervasive light of narrow emission lines from atoms of hydrogen, oxygen, and sulfur in the nebula. The field of view spans just over two degrees on the sky, so that it appears larger than four times the diameter of a full moon. The cosmic heart is found in the constellation of Cassiopeia, the boastful mythical Queen of Aethiopia .

Tomorrow's picture: double eclipse

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A Fleeting Double Eclipse of the Sun

A Fleeting Double Eclipse of the Sun:

Discover the cosmos! Each day a different image or photograph of our fascinating universe is featured, along with a brief explanation written by a professional astronomer.

2017 August 28

A Fleeting Double Eclipse of the Sun

Image Credit & Copyright: Simon Tang


Explanation: Last week, for a fraction of a second, the Sun was eclipsed twice. One week ago today, many people in North America were treated to a standard, single, partial solar eclipse. Fewer people, all congregated along a narrow path, experienced the eerie daytime darkness of a total solar eclipse. A dedicated few with fast enough camera equipment, however, were able to capture a double eclipse -- a simultaneous partial eclipse of the Sun by both the Moon and the International Space Station (ISS). The Earth-orbiting ISS crossed the Sun in less than a second, but to keep the ISS from appearing blurry, exposure times must be less than 1/1000th of a second. The featured image composite captured the ISS multiple times in succession as it zipped across the face of the Sun. The picture was taken from Huron, California in a specific color emitted by hydrogen which highlights the Sun's chromosphere, a layer hotter and higher up than the usually photographed photosphere.

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Tomorrow's picture: my blue saturn

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Saturn in Blue and Gold

Saturn in Blue and Gold:

Discover the cosmos! Each day a different image or photograph of our fascinating universe is featured, along with a brief explanation written by a professional astronomer.

2017 August 29

Saturn in Blue and Gold

Image Credit: Cassini Imaging Team, SSI, JPL, ESA, NASA


Explanation: Why is Saturn partly blue? The featured picture of Saturn approximates what a human would see if hovering close to the giant ringed world. The image was taken in 2006 March by the robot Cassini spacecraft now orbiting Saturn. Here Saturn's majestic rings appear directly only as a thin vertical line. The rings show their complex structure in the dark shadows they create on the image left. Saturn's fountain moon Enceladus, only about 500 kilometers across, is seen as the bump in the plane of the rings. The northern hemisphere of Saturn can appear partly blue for the same reason that Earth's skies can appear blue -- molecules in the cloudless portions of both planet's atmospheres are better at scattering blue light than red. When looking deep into Saturn's clouds, however, the natural gold hue of Saturn's clouds becomes dominant. It is not known why southern Saturn does not show the same blue hue -- one hypothesis holds that clouds are higher there. It is also not known why Saturn's clouds are colored gold. Next month, Cassini will end its mission with a final dramatic dive into Saturn's atmosphere.

Eclipses 2017: Memorable images submitted to APOD -- please "Like" your favorites.

Tomorrow's picture: princely eclipse

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A Waterspout in Florida

A Waterspout in Florida:

Discover the cosmos! Each day a different image or photograph of our fascinating universe is featured, along with a brief explanation written by a professional astronomer.

2017 September 3

Explanation: What's happening over the water? Pictured here is one of the better images yet recorded of a waterspout, a type of tornado that occurs over water. Waterspouts are spinning columns of rising moist air that typically form over warm water. Waterspouts can be as dangerous as tornadoes and can feature wind speeds over 200 kilometers per hour. Some waterspouts form away from thunderstorms and even during relatively fair weather. Waterspouts may be relatively transparent and initially visible only by an unusual pattern they create on the water. The featured image was taken in 2013 July near Tampa Bay, Florida. The Atlantic Ocean off the coast of Florida is arguably the most active area in the world for waterspouts, with hundreds forming each year. Some people speculate that waterspouts are responsible for some of the losses recorded in the Bermuda Triangle.

Saturns Rings from the Inside Out

Saturns Rings from the Inside Out:

Discover the cosmos! Each day a different image or photograph of our fascinating universe is featured, along with a brief explanation written by a professional astronomer.

2017 September 4

Explanation: What do Saturn's rings look like from Saturn? Images from the robotic spacecraft Cassini are providing humanity with this unprecedented vantage point as it nears the completion of its mission. Previous to Cassini's Grand Finale orbits, all images of Saturn's majestic ring system were taken from outside of the rings looking in. Pictured in the inset is the remarkable video, while the spacecraft's positions are depicted in the surrounding animation. Details of the complex rings are evident as the short time-lapse sequence begins, while the paper-thin thickness of the rings becomes apparent near the video's end. The featured images were taken on August 20. Cassini has only a few more orbits around Saturn left before it is directed to dive into the giant planet on September 15.

The Flash Spectrum of the Sun

The Flash Spectrum of the Sun:

Discover the cosmos! Each day a different image or photograph of our fascinating universe is featured, along with a brief explanation written by a professional astronomer.

2017 September 7

The Flash Spectrum of the Sun

Image Credit & Copyright: Yujing Qin (University of Arizona)


Explanation: In clear Madras, Oregon skies, this colorful eclipse composite captured the elusive chromospheric or flash spectrum of the Sun. Only three exposures, made on August 21 with telephoto lens and diffraction grating, are aligned in the frame. Directly imaged at the far left, the Sun's diamond ring-like appearance at the beginning and end of totality brackets a silhouette of the lunar disk at maximum eclipse. Spread by the diffraction grating into the spectrum of colors toward the right, the Sun's photospheric spectrum traces the two continuous streaks. They correspond to the diamond ring glimpses of the Sun's normally overwhelming disk. But individual eclipse images also appear at each wavelength of light emitted by atoms along the thin, fleeting arcs of the solar chromosphere. The brightest images, or strongest chromospheric emission, are due to Hydrogen atoms. Red hydrogen alpha emission is at the far right with blue and purple hydrogen series emission to the left. In between, the brightest yellow emission is caused by atoms of Helium, an element only first discovered in the flash spectrum of the Sun.

Tomorrow's picture: a great gig in the sky

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The Great Gig in the Sky

The Great Gig in the Sky:

Discover the cosmos! Each day a different image or photograph of our fascinating universe is featured, along with a brief explanation written by a professional astronomer.

2017 September 8

Explanation: There were no crowds on the beach at Phillips Lake, Oregon on August 21. But a few had come there to stand, for a moment, in the dark shadow of the Moon. From the beach, this unscripted mosaic photo records their much anticipated solar eclipse. In two vertical panels it catches the last few seconds of totality and the first instant of 3rd contact, just as the eclipse ends and sunlight faintly returns. Across the US those gathered along the path of totality also took pictures and shared their moment. And like those at Phillips Lake they may treasure the experience more than any planned or unplanned photograph of the total eclipse of the Sun.

Calm Waters and Geomagnetic Storm

Calm Waters and Geomagnetic Storm:

Discover the cosmos! Each day a different image or photograph of our fascinating universe is featured, along with a brief explanation written by a professional astronomer.

2017 September 9

Explanation: Very recognizable stars of the northern sky are a backdrop for calm waters in this moonlit sea and skyscape off Cape Cod, Massachusetts. Taken on September 7, the photo also records a colorful display of northern lights or aurora borealis triggered by a severe geomagnetic storm. Visible crossing the Sun, the giant solar active region responsible, AR 2673, is much larger than planet Earth. It has produced the strongest flare of the current solar cycle and and the Earth-directed coronal mass ejection in the last few days.

Swirling Around the Eye of Hurricane Irma

Swirling Around the Eye of Hurricane Irma:

Discover the cosmos! Each day a different image or photograph of our fascinating universe is featured, along with a brief explanation written by a professional astronomer.

2017 September 10


Swirling Around the Eye of Hurricane Irma

Video Credit: NASA, GOES-16 Satellite, SPoRT


Explanation: Why does a hurricane have an eye at its center? No one is yet sure. What happens in and around a hurricane's eye is well documented, though. Warm air rises around the eye's edges, cools, swirls, and spreads out over the large storm, sinking primarily at the far edges. Inside the low-pressure eye, air also sinks and warms -- which causes evaporation, calm, and clearing -- sunlight might even stream through. Just at the eye's edge is a towering eyewall, the area of the highest winds. It is particularly dangerous to go outside when the tranquil eye passes over because you are soon to experience, again, the storm's violent eyewall. Featured is one of the most dramatic videos yet taken of an eye and rotating eyewall. The time-lapse video was taken from space by NASA's GOES-16 satellite last week over one of the most powerful tropical cyclones in recorded history: Hurricane Irma. Hurricanes can be extremely dangerous and their perils are not confined to the storm's center.

Latest Images: Hurricanes Irma, Jose, and Katia

Tomorrow's picture: approaching saturn

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NASA Says James Webb Telescope will Study Solar System’s “Ocean Worlds”

NASA Says James Webb Telescope will Study Solar System’s “Ocean Worlds”:

In October of 2018, the James Webb Space Telescope (JWST) will be launched into orbit. As part of NASA’s Next Generation Space Telescope program, the JWST will spend the coming years studying every phase of cosmic history. This will involve probing the first light of the Universe (caused by the Big Bang), the first galaxies to form, and extra-solar planets in nearby star systems.

In addition to all of that, the JWST will also be dedicated to studying our Solar System. As NASA recently announced, the telescope will use its infrared capabilities to study two “Ocean Worlds” in our Solar System – Jupiter’s moon Europa and Saturn’s moon Enceladus. In so doing, it will add to observations previously made by NASA’s Galileo and Cassini orbiters and help guide future missions to these icy moons.

The moons were chosen by scientist who helped to develop the telescope (aka. guaranteed time observers) and are therefore given the privilege of being among the first to use it. Europa and Enceladus were added to the telescope’s list of targets since one of the primary goals of the telescope is to study the origins of life in the Universe. In addition to looking for habitable exoplanets, NASA also wants to study objects within our own Solar System.

Artist rendering showing an interior cross-section of the crust of Enceladus, which shows how hydrothermal activity may be causing the plumes of water at the moon’s surface. Credits: NASA-GSFC/SVS, NASA/JPL-Caltech/Southwest Research Institute

One of the main focuses will be on the plumes of water that have been observed breaking through the icy surfaces of Enceladus and Europa. Since 2005, scientists have known that Enceladus has plumes that periodically erupt from its southern polar region, spewing water and organic chemicals that replenish Saturn’s E-Ring. It has since discovered that these plumes reach all the way into the interior ocean that exists beneath Enceladus’ icy surface.

In 2012, astronomers using the Hubble Space Telescope detected similar plumes coming from Europa. These plumes were spotted coming from the moon’s southern hemisphere, and were estimated to reach up to 200 km (125 miles) into space. Subsequent studies indicated that these plumes were intermittent, and presumably rained water and organic materials from the interior back onto the surface.

These observations were especially intriguing since they bolstered the case for Europa and Enceladus having interior, warm-water oceans that could harbor life. These oceans are believed to be the result of geological activity in the interior that is caused by tidal flexing. Based on the evidence gathered by the Galileo and Cassini orbiters, scientists have theorized that these surface plumes are the result of these same geological processes.

The presence of this activity could also means that these moons have hydrothermal vents located at their core-mantle boundaries. On Earth, hydrothermal vents (located on the ocean floor) are believed to have played a major role in the emergence of life. As such, their existence on other bodies within the Solar System is viewed as a possible indication of extra-terrestrial life.



The effort to study these “Ocean Worlds” will be led by Geronimo Villanueva, a planetary scientist at NASA’s Goddard Space Flight Center. As he explained in a recent NASA press statement, he and his team will be addressing certain fundamental questions:

“Are they made of water ice? Is hot water vapor being released? What is the temperature of the active regions and the emitted water? Webb telescope’s measurements will allow us to address these questions with unprecedented accuracy and precision.”

Villanueva’s team is part of a larger effort to study the Solar System, which is being led by Heidi Hammel – the executive VP of the Association of Universities for Research in Astronomy (AURA). As she described the JWST’s “Ocean World” campaign to Universe Today via email:

“We will be seeking signatures of plume activity on these ocean worlds as well as active spots. With the near-infrared camera of NIRCAM, we will have just enough spatial resolution to distinguish general regions of the moons that could be “active” (creating plumes). We will also use spectroscopy (examining specific colors of light) to sense the presence of water, methane and several other organic species in plume material.”

Possible spectroscopy results from one of Europa’s water plumes. This is an example of the data the Webb telescope could return. Credit: NASA-GSFC/SVS/Hubble Space Telescope/Stefanie Milam/Geronimo Villanueva

To study Europa, Villanueva and his colleagues will take high-resolution imagery of Europa using the JWST’s near-infrared camera (NIRCam). These will be used to study the moon’s surface and search for hot spots that are indicative of plumes and geological activity. Once a plume is located, the team will determine its composition using Webb’s near-infrared spectrograph (NIRSpec) and mid-infrared instrument (MIRI).

For Enceladus, the team will be analyze the molecular composition of its plumes and perform a broad analysis of its surface features. Due to its small size, high-resolution of the surface will not be possible, but this should not be a problem since the Cassini orbiter already mapped much of its surface terrain. All told, Cassini has spent the past 13 years studying the Saturn system and will conclude the “Grande Finale” phase of its mission this September 15th.

These surveys, it is hoped, will find evidence of organic signatures in the plumes, such as methane, ethanol and ethane. To be fair, there are no guarantees that the JWST’s observations will coincide with plumes coming from these moons, or that the emissions will have enough organic molecules in them to be detectable. Moreover, these indicators could also be caused by geological processes.

Nevertheless, the JWST is sure to provide evidence that will allow scientists to better characterize the active regions of these moons. It is also anticipated that it will be able to pinpoint locations that will be of interest for future missions, such as NASA’s Europa Clipper mission. Consisting of an orbiter and lander, this mission – which is expected to launch sometime in the 2020s – will attempt to determine if Europa is habitable.



As Dr. Hammel explained, the study of these two “Ocean Moons” is also intended to advance our understanding about the origins of life in the Universe:

“These two ocean moons are thought to provide environments that may harbor water-based life as we know it.  At this point, the issue of life elsewhere is completely unknown, though there is much speculation.  JWST can move us closer to understanding these potentially habitable environments, complementing robotic spacecraft missions that are currently in development (Europa Clipper) and may be planned for the future.   At the same time, JWST will be examining the far more distant potentially habitable environments of planets around other stars.  These two lines of exploration – local and distant – allow us to make significant advances in the search for life elsewhere.”

Once deployed, the JWST will be the most powerful space telescope ever built, relying on eighteen segmented mirrors and a suite of instruments to study the infrared Universe. While it is not meant to replace the Hubble Space Telescope, it is in many ways the natural heir to this historic mission. And it is certainly expected to expand on many of Hubble’s greatest discoveries, not the least of which are here in the Solar System.

Be sure to check out this video on the kinds of spectrographic data the JWST will provide in the coming years, courtesy of NASA:



Further Reading: NASA

The post NASA Says James Webb Telescope will Study Solar System’s “Ocean Worlds” appeared first on Universe Today.

Watch Asteroid 3122 Florence Zip Past Earth This Weekend

Watch Asteroid 3122 Florence Zip Past Earth This Weekend:

An artist’s conception of an NEO asteroid similar to 3122 Florence orbiting the Sun. Credit: NASA/JPL.

Ready to hunt for low-flying space rocks? We’ve got an interesting pass of a Near Earth Asteroid (NEA) this upcoming U.S. Labor Day weekend, one that just slides over the +10^th magnitude line into binocular range.

We’re talking about asteroid 3122 Florence, which passes 4.4 million miles from our fair planet (that’s 7 million kilometers, about 18 times the distance from Earth to the Moon) this Friday on September 1^st at 12:06 Universal Time (UT)/ 8:06 AM Eastern Daylight Saving Time (EDT).

Universe Today ran an article on the close pass about a week ago. Now, we’d like to show you how to see this asteroid as it glides by.

Ordinarily, a four million mile pass (about 4.7% of an astronomical unit, just under the criterion to make 3122 Florence a Near Earth Object) isn’t enough to grab our attention. Lots of asteroids pass closer weekly, and 3122 Florence is certainly no danger to the Earth this or any week in the near future. What makes this asteroid an attractive target is its size: NASA’s NEOWISE and Spitzer infrared telescope missions estimate that 3122 Florence is about 2.7 miles (4.4 kilometers) in diameter, a pretty good-sized chunk of rock as near Earth asteroids go.

The inclined orbit of 3122 Florence. Credit: NASA/JPL.

The last large asteroid with a similar close approach was 4179 Toutatis, which passed just under four lunar distances (a little under a million miles) from the Earth on September 29th, 2004.

Asteroid 3122 Florence (1981 ET3) was discovered by prolific asteroid hunter Schelte J. Bus from Siding Spring observatory in Australia on the night of March 2nd, 1981. Named after social reformer and founder of modern nursing Florence Nightingale, this weekend’s pass is the closest 3122 Florence gets to Earth over a 600 year plus span, running from 1890 (well before its discovery) out past 2500 AD.

Plans are afoot to ping 3122 Florence using Goldstone and Arecibo radars as it passes by the weekend. we might just see if it has a any attending moonlets or a strange bifurcated shape like comets 67/P Churyumov-Gerasimenko or Comet 45/P Honda-Mrkos-Pajdušáková very soon.

Asteroid 2014 JO25 imaged by Arecibo earlier this year… are contact binary ‘rubber-duck’ shaped asteroids and comets a thing? Credit: NASA/Arecibo/NSF.

3122 Florence has an inclined orbit, tilted 22 degrees in respect to the ecliptic plane. Orbiting the Sun once every 859 days, 3122 Florence travels from around 1 to 2.5 AUs from the Sun, making it an Amor class asteroid which journeys beyond the orbit of Mars and approaches but doesn’t pass interior to the orbit of the Earth.

This week’s pass sees 3122 Florence rapidly vaulting up from the southern to northern hemisphere.

This apparition culminates on Friday, September 1^st, at 12:06 UT as the asteroid crosses the along the border of the constellations Equuleus and Delphinus at closest approach, reaching +9^th magnitude. 3122 Florence will be moving at 20′ per hour (that’s about 2/3rds the diameter of the Full Moon) at closest approach, fast enough that you’ll notice its motion against the background stars in a low power field of view after about 10 minutes or so.

The path of 3122 Florence through the sky this week, times for the tick marks are in EDT (UT-4 hours). Credit: Starry Night Education software.

3122 Florence crosses through the constellations Piscis Austrinus, Capricornus, Aquarius, Equuleus and Delphinus this week. Keep in mind, the Moon is headed towards Full next week on September 6th, making the next few evenings a good time to track this fleeting space rock down.

3122 Florence from August 28th, about 8 million kilometers from the Earth. The asteroid is the center dot, while the streak to the left is the geostationary satellite AMC-14. Credit: the Virtual Telescope Project.

Finding 3122 Florence

3122 Florence races across the ecliptic northward on the night of August 29^th and also crosses the celestial equator on September 1^st

Tonight is also a good time to track down 3122 Florence, as it passes just 16′ from +3.8 magnitude star Zeta Capricorni. It also threads its way through the tiny the diamond-shaped asterism of Delphinus the Dolphin just over week after its closest pass on the evening of Saturday, September 9^th.

Currently, 3122 Florence is 45 degrees above the southern horizon around local midnight for observers based along 30 degrees north latitude. The best view during Friday’s pass is from the Pacific Rim, including Australia, New Zealand and surrounding regions at closest approach.

The orientation of the Earth as seen from asteroid 3122 Florence during Friday’s closest approach. Credit: Starry Night Education software.

North American viewers will get a good view at local midnight just about eight hours prior to closest approach on the night of August 31^st/September 1^st, about 60 degrees above the southern horizon. The next good views occur the following evening about 16 hours after closest approach, as the asteroid is receding but 10 degrees higher above the southern horizon.

The 24 hour celestial path of of 3122 Florence through the night sky, centered on the September 1st closest approach. Tick mark times are in EDT (UT-4 hours). Created using Starry Night Education software.

A series short wide field exposures over about an hour revealing stars down to +10 magnitude should reveal the motion of 3122 Florence against the starry background. A good visual alternative is to sketch the suspect star field about 10 minutes apart, carefully looking for a ‘star’ that has moved during the intervening time.

JPL Horizons is a good place to generate accurate right ascension and declination coordinates for 3122 Florence to aid you in your quest. This one is distant enough to simple geocentric coordinates should suffice, and observer parallax shouldn’t shift the position of the asteroid significantly.

Clouded out? The good folks over at the Virtual Telescope Project will be featuring 3122 Florence during a live webcast starting on Thursday, August 31^st at 19:30 UT/3:30 PM EDT.

We can be thankful that 3122 Florence isn’t headed Earthward, as it’s perhaps about half the size of the 10-15 kilometer diameter Chicxulub impactor that hit the Yucatan 65 million years ago, causing a very bad day for the dinosaurs. Plus, it would just be weird if an asteroid named after humanitarian Florence Nightingale caused the extinction of humanity…

And this is a great pre-show for a smaller and closer anticipated asteroid pass coming up in a few short weeks, as 2012 TC4 buzzes the Earth on October 12th, 2017.

Good luck in your quest to find 3122 Florence… let us know what you see!

The post Watch Asteroid 3122 Florence Zip Past Earth This Weekend appeared first on Universe Today.

Exoplanet-Hunters Detect Two New “Warm Jupiters”

Exoplanet-Hunters Detect Two New “Warm Jupiters”:

The study of extra-solar planets has turned up some rather interesting candidates in the past few years. As of August 1st, 2017, a total of 3,639 exoplanets have been discovered in 2,729 planetary systems and 612 multiple planetary systems. Many of these discoveries have challenged conventional thinking about planets, especially where their sizes and distances from their suns are concerned.

According to a study by an international team of astronomers, the latest exoplanet discoveries are in keeping with this trend. Known as EPIC 211418729b and EPIC 211442297b, these two gas giants orbit stars that are located about 1569 and 1360 light-years from Earth (respectively) and are similar in size to Jupiter. Combined with their relatively close orbit to their stars, the team has designated them as “Warm Jupiters”.

The study, titled “EPIC 211418729b and EPIC 211442297b: Two Transiting Warm Jupiters“, recently appeared online. Led by Avi Shporer – a postdoctoral scholar with the Geological and Planetary Sciences (GPS) division at the California Institute of Technology (Caltech) – the team relied on data from the Kepler and K2 missions, and follow-up observations with multiple ground-based telescopes, to determine the sizes, masses and orbits of these planets.

Simulation of the turbulent atmosphere of a hot, gaseous planet, based on data from NASA’s Spitzer Space Telescope. Credits: NASA/JPL-Caltech/MIT/Principia College

As they indicate in their study, the two planets were initially identified as transiting planet candidates by the K2 mission. In other words, they were initially detected through the transit method, where astronomers measure dips in a star brightness to confirm that a planet is passing between the observer and the star. These observations took place during K2‘s Campaign 5 observations, which took place between April 27th and July 10th, 2015.

The team then conducted follow-up observations using the Keck II telescope (located at the W.M. Keck Observatory in Hawaii) and the Gemini North Telescope (at the Gemini Observatory, also in Hawaii). These observations, conducted from January 2016 to May 2017, were then combined with spectral data and radial velocity measurements from the High Resolution Echelle Spectrometer (HIRES) the on the Keck I telescope.

Finally, they added photometric data from the Cerro Tololo Inter-American Observatory (CTIO) in Chile, the South African Astronomical Observatory (SAAO), and the Siding Spring Observatory (SSO) in Australia. These follow-up observations confirmed the presence of these two exoplanets. As they wrote in the study:

“We have discovered two transiting warm Jupiter exoplanets initially identified as transiting candidates in K2 photometry… Both planets are among the longest period transiting gas giant planets with a measured mass, and they are orbiting relatively old host stars. Both planets are not inflated as their radii are consistent with theoretical expectations.”

The transit light curve of EPIC 211418729b. Credit: Shporer (et al.)

From their observations, the team was also able to produce estimates on the planets respective sizes, masses and orbital periods. Whereas EPIC 211418729 b measures 0.942 Jupiter radii, has approximately 1.85 Jupiter masses and orbital period of 11.4 days, EPIC 211442297 b measures 1.115 Jupiter radii, has approximately 0.84 Jupiter masses and an orbital period of 20.3 days.

Based on their estimates, these planets experience surface temperatures of up to 719 K (445.85 °C; 834.5 °F) and 682 K (408.85°C; 768 °F), respectively. As such, they classified these planets as “Warm Jupiters”, since they fall short of what is considered typical for “Hot Jupiters” – which have exotic atmosphere’s that experience temperatures as high as several thousand kelvin.

The researchers noted that based on their orbital periods, these two planets have some of the longest orbital periods of any transiting gas giant (i.e. those that have been detected using the transit method) detected to date. Or as they state in their study:

“Both EPIC 211418729b and EPIC 211442297b are among the longest period transiting gas giant planets with a measured mass. In fact, according to the NASA Exoplanet Archive (Akeson et al. 2013) EPIC 211442297b is currently the longest period K2 transiting exoplanet with a well constrained mass.”

Artist’s conception of a “Hot Jupiter” orbiting close to its star. Credit: NASA/JPL-Caltech/T. Pyle (SSC)

Another interesting observation was the fact that neither of these exoplanets were inflated, which is something they did not anticipate. In the case of Hot Jupiters, the atmospheres undergo expansion as a result of the amount of solar irradiation they receive, resulting in what the team refers to as a “radius-irradiation correlation” in their paper. In other words, Hot Jupiters are massive, but are also known to have low densities compared to cooler gas giants.

Instead, the team found that both EPIC 211418729b and EPIC 211442297b had radii that were consistent with what theoretical models predict for gas giants of their mass. Their results also led them to make some tentative conclusions about the planets’ structures and compositions. As they wrote:

“Both planets are not inflated compared to theoretical expectations, unlike many other planets in the diagram. Their positions are close to or consistent with theoretical expectations for a planet with little to no rocky core, for EPIC 211442297b, and a planet with a significant rocky core for EPIC 211418729b.”

These results suggest that solar irradiation does not play a significant role in determining the radius of Warm Jupiters. It also raises some interesting questions about the correlation between radii and irradiation with other gas giants. In the future, EPIC 211418729b and EPIC 211442297b will be targets of future K2 observations during the mission’s Campaign 18 – which will run from May to August 2018.

These observations are sure to offer some additional insight into these planets and the mysteries this study has raised. Future surveys of transiting exoplanets – conducting by next-generation instruments like the Transiting Exoplanet Survey Satellites (TESS) – and direct-imaging surveys conducted by the James Webb Space Telescope (JWST) are sure to reveal even more about distant, exotic exoplanets.

Further Reading: arXiv

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Breakthrough Detects Repeating Fast Radio Bursts Coming from Distant Galaxy

Breakthrough Detects Repeating Fast Radio Bursts Coming from Distant Galaxy:

In July of 2015, Russian billionaire Yuri Milner announced the creation of Breakthrough Listen, a decade-long project that would conduct the largest survey to date for signs of extra-terrestrial communications (ETI). As part of his non-profit organization, Breakthrough Initiatives, this survey would rely on the latest in instrumentation and software to observe the 1,000,000 closest stars and 100 closest galaxies.

Using the Green Bank Radio Telescope in West Virginia, the Listen science team at UC Berkeley has been observing distant stars for over a year now. And less than a week ago, they observed 15 Fast Radio Bursts (FRBs) coming from a dwarf galaxy located three billion light-years away. According to a study that described their findings, this was the first time that repeating FRBs have been seen coming from this source at these frequencies.

The team’s study, titled “FRB 121102: Detection at 4 – 8 GHz band with Breakthrough Listen backend at Green Bank“, was recently published in The Astronomers Telegraph. Led by Dr. Vishal Gajjar – a postdoctoral researcher at the University of California, Berkeley – the team conducted a detailed survey of FRB 121102. This repeating FRB source is located in a dwarf galaxy in Auriga constellation, some 3 billion light-years from Earth.

The NSF’s Arecibo Observatory, which is located in Puerto Rico, is the world largest radio telescope. Credit: NAIC

To clarify, FRBs are brief, bright pulses of radio waves that are periodically detected coming from distant galaxies. This strange astronomical phenomena was first detected in 2007 by Duncan Lorimer and David Narkovic using the Parkes Telescope in Australia. To honor their discovery, FRBs are sometimes referred to as “Lorimer Bursts”. Many FRB sources have been confirmed since then, some of which were found repeating.

The source known as FRB 121101 was discovered back on November 2nd, 2012, by astronomers using the Arecibo radio telescope. At the time, it was the first FRB to be discovered; and by 2015, it became the first FRB to be seen repeating. This effectively ruled out the possibility that repeating FRBs were caused by catastrophic events, which had previously been theorized.

And in 2016, FRB 121102 was the first FRB to have its location pinpointed to such a degree that its host galaxy could be identified. As such, the Listen science team at UC Berkeley was sure to add FRB 121102 to their list of targets. And in the early hours of Saturday, August 26th, Dr. Vishal Gajjar – a postdoctoral researcher at UC Berkeley – observed FRB 121102 using the Green Bank Radio Telescope (GBRT) in West Virginia.

Using the Digital Backend instrument on the GBRT, Dr. Gajjar and the Listen team observed FRB 121102 for five hours. From this, they accumulating 400 terabytes of data in the entire 4 to 8 GHz frequency band which they then analyzed for signs of short pulses over a broad range of frequencies. What they found was evidence of 15 new pulses coming from FRB 121102, which confirmed that it was in a newly active state.

The Green Bank Telescope, located in West Virginia. Credit: NRAO

In addition, their observations revealed that the brightest of these 15 emissions occurred at around 7 GHz. This was higher than any repeating FRBs seen to date, which indicated for the first time that they can occur at frequencies higher than previously thought. Last, but not least, the high-resolution data the Listen team collected is expected to yield valuable insights into FRBs for years to come.

This was made possible thanks to the Digital Backend instrument on the GBRT, which is able to record several GHz of bandwidth simultaneously and split the information into billions of individuals channels. This enables scientists to study the proprieties and the frequency spectrum of FRBs with greater precision, and should lead to new theories about the causes of these radio emissions.

So even if these particular signals should prove to not be an indication of extra-terrestrial intelligence, Listen is still pushing the boundaries of what is possible with radio astronomy. And given that Breakthrough Listen is less than two years into its proposed ten-year survey, we can expect many more sources to be observed and studied in the coming years. If there’s evidence of ETI to be found, we’re sure to find out about it sooner or later!

And be sure to check out this video of the Green Bank Telescope and the surveys it allows for, courtesy of Berkeley SETI:



Further Reading: Breakthrough Initiatives

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Hubble Spots First Indications of Water on TRAPPIST-1s Planets

Hubble Spots First Indications of Water on TRAPPIST-1s Planets:

In February of 2017, astronomers from the European Southern Observatory (ESO) announced the discovery of seven rocky planets around the nearby star of TRAPPIST-1. Not only was this the largest number of Earth-like planets discovered in a single star system to date, the news was also bolstered by the fact that three of these planets were found to orbit within the star’s habitable zone.

Since that time, multiple studies have been conducted to ascertain the likelihood that these planets are actually habitable. Thanks to an international team of scientists who used the Hubble Space Telescope to study the system’s planets, we now have the first clues as to whether or not water (a key ingredient to life as we know it) exists on any of TRAPPIST-1s rocky worlds.

The team’s study, titled “Temporal Evolution of the High-Energy Irradiation and Water Content of TRAPPIST-1 Exoplanets“, recently appeared on the Hubble site. Led by Swiss astronomer Vincent Bourrier from the Observatoire de l’Université de Genève, the team relied on Hubble’s Space Telescope Imaging Spectrograph (STIS) to study the amount of ultraviolet radiation each of the TRAPPIST-1 planets receives.

Artist concepts of the seven planets of TRAPPIST-1 with their orbital periods, distances from their star, radii and masses as compared to those of Earth. Credit: NASA/JPL

As Bourrier explained in a Hubble press release, this helped them to determine the water content of the system’s seven planets:

“Ultraviolet radiation is an important factor in the atmospheric evolution of planets. As in our own atmosphere, where ultraviolet sunlight breaks molecules apart, ultraviolet starlight can break water vapor in the atmospheres of exoplanets into hydrogen and oxygen.”

How ultraviolet radiation interacts with a planet’s atmosphere is important when it comes to assessing the potential habitability of a planet. Whereas lower-energy UV radiation causes photodissociation, a process where water molecules break down into oxygen and hydrogen, extreme ultraviolet rays (XUV radiation) and x-rays cause the upper atmosphere of a planet to heat up – which causes the hydrogen and oxygen to escape.

Since hydrogen is lighter than oxygen, it is more easily lost to space where its spectra can be observed. This is precisely what Bourrier and his team did. By monitoring the TRAPPIST-1 planets spectra for signs of hydrogen loss, the team was effectively able to gauge their water content. What they found was that the UV radiation emitted by TRAPPIST-1 suggests that its planets could have lost quite a lot of water during their history.

The losses were most severe for the innermost planets – TRAPPIST-1b and 1c – which receive the most UV radiation from their star. In fact, the team estimates that these planets could have lost more than 20 Earth-oceans worth of water in the course of the system’s history – which is estimated to be between 5.4 and 9.8 billion years old. In other words, these inner planets would be bone dry and most definitely sterile.

This illustration shows the seven TRAPPIST-1 planets as they might look as viewed from Earth using a fictional, incredibly powerful telescope. Credit: NASA/JPL-Caltech

However, these same findings also suggest that the outer planets of the system have lost significantly less water over time, which could mean that they still possess abundant amounts on their surfaces. This includes the three planets that are within the star’s habitable zone – TRAPPIST-1e, f and g – which indicates that these planets could be habitable after all.

These findings are bolstered by the calculated water loss and geophysical water release rates, which also favor the idea that the more-massive and outermost planets have retained most of their water over time. These findings are very significant, in that they further demonstrate that atmospheric escape and evolution are closely linked on the planets of the TRAPPIST-1 system.

The findings are also encouraging, since previous studies that considered atmospheric loss in this system painted a rather grim picture. These include those that indicated that TRAPPIST-1 experiences too much flare, that even calm red dwarfs subject their planets to intense radiation over time, and that the distance between TRAPPIST-1 and its respective planets would mean that solar wind would be deposited directly onto their atmospheres.

In other words, these studies cast doubt on whether or not stars that orbit M-type (red dwarf) stars would be able to retain their atmospheres over time – even if they had an Earth-like atmosphere and magnetosphere. Like Mars, this research indicated that atmospheric stripping caused by solar wind would inevitably render their surfaces cold, desiccated, and lifeless.

Artist’s illustration showing the difference  TRAPPIST-1 in relation to our Sun. Credit: ESO

In short, this is one of the few pieces of good news we’ve received since the existence of seven planets in the TRAPPIST-1 system (and three potentially habitable ones) was first announced. It’s also a positive indication as far as the habitability of red dwarf star systems go. In recent years, many of those impressive exoplanet finds have taken place around red dwarf stars – i.e. Proxima b, LHS 1140b, Gliese 581g, Gliese 625b, and Gliese 682c.

Given the number of rocky planets that have been detected orbiting this type of star – and the fact that they are the most common in in the Universe (accounting for 70% of stars in the Milky Way alone) – knowing that they could support habitable planets is certainly welcome! But of course, Bourrier and his colleagues emphasize that the study is not conclusive, and further research is needed to determine if any of the TRAPPIST-1 planets are actually watery.

As Bourieer indicated, this will most likely involve next-generation telescopes:

“While our results suggest that the outer planets are the best candidates to search for water with the upcoming James Webb Space Telescope, they also highlight the need for theoretical studies and complementary observations at all wavelengths to determine the nature of the TRAPPIST-1 planets and their potential habitability.”

Rocky planets around the most common type of star, the potential to retain water, and 1oo billion potential planets in the Milky Way Galaxy alone. One thing is for sure: the James Webb Space Telescope is going to have its hands full once it is deployed in October of 2018!

And be sure to check out this animation of the TRAPPIST-1 system as well, courtesy of L. Calçada and the ESO:



Further Reading: Hubble Space Telescope, HST (2)

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