Stellar radiation may preclude Earth-like atmosphere on Proxima b

Stellar radiation may preclude Earth-like atmosphere on Proxima b:

This artist’s impression shows a view of the surface of the planet Proxima b orbiting the red dwarf star Proxima Centauri, the closest star to the Solar System. The double star Alpha Centauri AB also appears in the image. Proxima b is a little more massive than the Earth and orbits in the habitable zone around Proxima Centauri, where the temperature is suitable for liquid water to exist on its surface. Image & Caption Credit: ESO / M. Kornmesser

The exoplanet closest to the Solar System, Proxima b, is located in its star’s habitable zone but may be unable to support life because radiation from its host star is likely to strip away its atmosphere, according to a new study based on a computer simulation.

A group of scientists led by Katherine Garcia-Sage of NASA’s Goddard Space Flight Center in Greenbelt, Maryland, created a computer model that placed Earth’s atmosphere, magnetic field, and gravity at the location of Proxima b. Using data obtained by NASA’s Chandra X-ray Observatory, they determined the level of radiation emitted by the host star, Proxima Centauri. Their goal was to determine the fate of Earth if it orbited in Proxima b’s location.

At its orbit, the exoplanet Proxima b likely couldn’t sustain an Earth-like atmosphere. Credits: NASA’s Goddard Space Flight Center / Mary Pat Hrybyk-Keith

The nature of the real Proxima b’s atmosphere is unknown because scientists have not observed the planet passing in front of its star. Observation of transits is the method researchers use to learn about planets’ atmospheres.

“We decided to take the only habitable planet we know of so far – Earth – and put it where Proxima b is,” Garcia-Sage said.

A star’s habitable zone is defined as the distance an orbiting planet can have liquid water on its surface. However, being in a habitable zone does not guarantee a planet is habitable.

To be habitable for life as we know it, a planet must have an atmosphere – one that regulates climate, maintains a surface pressure capable of supporting liquid water, enables the presence of life’s chemical building blocks, and protects it from dangerous radiation and space weather.

Significantly closer to its star than Earth is to the Sun, Proxima b is subject to the star’s regular flares and intense radiation hundreds of times the amount Earth receives from the Sun. In the computer model, that radiation stripped away the planet’s atmosphere at a rate up to 10,000 times greater than solar radiation does to Earth.

Red dwarf stars like Proxima Centauri and TRAPPIST-1, another star with planets in its habitable zone, emit extreme ultraviolet radiation, which ionizes gases in the atmosphere of an orbiting planet. The process removes electrons from its atmosphere, creating a stream of electrically-charged particles that are energetic enough to completely escape the planet’s gravity.

The high level of radiation that planets such as Proxima b are exposed to is enough to strip away heavier elements in an atmosphere, such as nitrogen and oxygen, in addition to hydrogen.

“This was a simple calculation based on average activity from the host star,” Garcia-Sage said. “It doesn’t consider variations like extreme heating in the star’s atmosphere or violent stellar disturbances to the exoplanet’s magnetic field – things we’d expect provide even more ionizing radiation and atmospheric escape.”

Two other factors that could affect the rate of atmospheric loss were also inputted into the computer model. These are the temperature of the planet’s neutral atmosphere, also known as its thermosphere, as well as the size of the area on the planet that experiences atmospheric escape.

Stellar radiation was found to heat up the thermosphere, increasing the rate of atmospheric loss. Areas on a planet over which atmosphere is lost are known as polar caps. The level of atmospheric escape is affected by a planet’s magnetic field lines. If the magnetic field lines at a planet’s magnetic poles are closed, the size of the polar cap is limited, and charged particles remain trapped, reducing the escape level. In contrast, if magnetic field lines are open, the escape rate of charged particles increases.

If Proxima b’s thermosphere has very high temperatures and its magnetic field must remain open, it could lose an atmosphere equivalent to Earth’s in just 100 million years. Low thermosphere temperatures and a closed magnetic field extend the duration it would take to lose an Earth atmosphere to slightly more than two billion years.

Proxima b is estimated to be approximately four billion years old.

Jeremy Drake of the Harvard-Smithsonian Center for Astrophysics, who took part in the study, said the level of atmospheric loss on Proxima b makes its habitability “implausible” and calls into question the habitability of Earth-like planets orbiting other red dwarf stars. These cool stars, the most common in the galaxy, have topped scientists’ searches for habitable worlds.

NASA’s Nexus for Exoplanet System Science (NExSS) coalition, which is charged with searching for life on exoplanets, and NASA’s Astrobiology Institute contributed to the study. Those findings are published in The Astrophysical Journal Letters.



The post Stellar radiation may preclude Earth-like atmosphere on Proxima b appeared first on SpaceFlight Insider.

Rogue 'Double Planet' Is Actually 2 Failed Stars

Rogue 'Double Planet' Is Actually 2 Failed Stars:

The brown dwarf binary 2MASS J11193254−1137466.

Credit: W. Best et al.

A pair of objects drifting in interstellar space may look like a rogue "double planet," but it's actually two failed stars, a new study finds.The duo is the most lightweight binary system ever discovered and may be the closest approximation of a free-floating "double planet" that astronomers have found so far.

The object, named 2MASS J11193254−1137466, is located about 95 light-years from Earth, in the constellation Hydra. A 2016 study suggested it was a free-floating planet-like body — a "rogue" object without a parent star.

This previous research estimated that the mass of this object, also known as 2M1119, was four to eight times that of Jupiter. This suggested it was a brown dwarf, also known as a failed star. [Brown Dwarfs: Strange Failed Stars of the Universe Explained (Infographic)]

Brown dwarfs, like regular stars, begin as clouds of gas and dust that collapse under their own gravity. However, brown dwarfs lack the mass to squeeze atoms enough to trigger nuclear fusion. Instead, they are not quite planets and not quite stars.

Now, with the aid of the Keck II telescope in Hawaii, scientists have found that 2M1119 is actually two brown dwarfs, of equal brightness, orbiting each other.

"The fact that it was a binary, not another boring single system, was completely new," study co-author Trent Dupuy, an astronomer at the University of Texas at Austin, told Space.com. "Maybe it means that planetary-mass objects can form like stars and also, very rarely, form like binary stars."

To learn more about this binary, the researchers analyzed a collection of a few dozen 10-million-year-old stars located about 23 light-years from the pair. Known as the TW Hydrae Association, this is the youngest group of stars near Earth's solar system. It measures about 260 light-years across and, as a whole, is about 130 to 195 light-years from Earth, Dupuy said.

Based on the position and motion of 2M1119, the scientists found that there was an 82 percent chance that it was a member of the TW Hydrae Association. This suggested that 2M1119, too, was about 10 million years old. This knowledge, in combination with the spectrum of light detected from 2M1119, helped the researchers calculate other properties of the brown dwarfs.

The scientists estimated that the brown dwarfs in this pair are separated by about 334 million miles (538 million kilometers), or slightly less than four times the distance between Earth and the sun. The mass of each brown dwarf is about 3.7 times that of Jupiter, which makes the pair the lowest-mass binary system discovered to date outside Earth's solar system.

A newly scrutinized brown-dwarf binary system appears to be a member of the so-called TW Hydrae Association, about two dozen young stars that move together near the sun's neighborhood.

Credit: David Rodriguez/University of Western Ontario/Carnegie Institution of Washington DTM


"No one has ever found a binary brown dwarf that has components that are this low in mass," said study lead author William Best, an astronomer at the University of Hawaii at Honolulu. "We weren't sure a binary like this could even exist."

Whether these newfound bodies should be called planets or brown dwarfs is a tricky question, Best said.

"The components of 2M1119 fit the International Astronomical Union definition for planet — less than 13 Jupiter masses — and similar single objects have recently been called 'lonely planets' or 'rogue planets,'" Best told Space.com. "But we also commonly think of planets as things that are orbiting stars. In that sense, 'rogue planets' are not planets at all because they are not orbiting stars — they are floating out in space by themselves, and almost certainly formed like stars do. So, objects like this challenge our definitions of planet and brown dwarf.

"Bottom line — 2M1119 does not obviously fit into either of the planet and brown dwarf boxes," Best added. "I think the most accurate description for 2M1119 is 'planetary-mass binary brown dwarf.' I realize that's an unpoetic mouthful — 'lonely double planet' is certainly prettier. Hopefully, we'll develop a better definition in the future."

Brown dwarfs are thought to form the way stars do, Best said. "One open question in astronomy is, 'What is the smallest-mass brown dwarf that can form, and what is the lowest-mass binary that can form — that is, how low can star formation go?'" Best said. "This discovery sets a new record for binaries. Anyone working on the theory of how stars and brown dwarfs form needs to be able to explain how this binary formed. And there may be even lower-mass ones out there."

The scientists detailed their findings online June 23 in The Astrophysical Journal Letters.

Follow Charles Q. Choi on Twitter @cqchoi. Follow us @Spacedotcom, Facebook and Google+. Original article on Space.com.

Saturn Basks in Sunlight in Spectacular Summer Solstice View (Photo)

Saturn Basks in Sunlight in Spectacular Summer Solstice View (Photo):

On July 31, 2017, NASA released an impressive vista of sunlight reflecting off of Saturn's northern hemisphere.

Credit: NASA/JPL-Caltech/Space Science Institute

Saturn emerges from the shadows to bathe in sunlight in a new view of the planet's infrequent summer solstice.

The Cassini spacecraft captured the beautiful photo of the ringed planet in April 2017. The image of Saturn's northern hemisphere includes lines across its cloudy atmosphere and a view of the hexagonal north pole outlined clearly. Cassini captured the sight when the spacecraft was 17 degrees above the ring plane and about 733,000 miles (1.2 million kilometers) above Saturn's surface.

Saturn experiences seasons, and Cassini has an "unparalleled opportunity" to observe how the giant belted planet responds to changes as it receives continuous light on its northern side, NASA officials said in a statement. A Saturn solstice occurs about once every 15 Earth years, and as Saturn approaches solstice at its north pole, the days in that hemisphere grow longer than at any other point along its roughly 30-Earth-year orbit. [More Photos: Saturn's Weird Hexagon Storms]

Saturn's northern hemisphere continues to receive most of the sun's light until the planet's equinox, when the sun shines equally over both halves of Saturn. After the photograph was taken, Saturn continued to receive more sunlight as Saturn's summer solstice officially arrived a month later, on May 24. [Cassini Spots 'Ghostly Curtains of Light' Near Saturn's South Pole]

The hexagonal vortex at Saturn's north pole changed color significantly between June 2013 (left) and April 2017 (right), as seen in views from the Cassini spacecraft. For the left image, each frame occurs approximately 130 minutes after the previous one, and for the right, each frame follows after an average of 230 minutes. Researchers combined images taken with the spacecraft's red, green and blue filters for the natural-color views.

Credit: NASA/JPL-Caltech/Space Science Institute/Hampton University


One seasonal change is a shift in color in the northern pole region. A few years ago, Cassini captured images with its wide-angle camera to show astronomers a distinct change in hue: from a darker tinge in November 2012 to a creamy tint in September 2016.

The spacecraft is operated by a collaborative mission of NASA, the European Space Agency and the Italian Space Agency. On Sept. 15, 2017, the spacecraft will complete a final dive into Saturn's atmosphere over the course of several orbits, to prevent the low-fueled spacecraft from spreading microbes to any of Saturn's moons.

Follow Doris Elin Salazar on Twitter @salazar_elin. Follow us @Spacedotcom, Facebook and Google+. Original article on Space.com.

Hubble Telescope Detects Stratosphere on Huge Alien Planet

Hubble Telescope Detects Stratosphere on Huge Alien Planet:

This artist's illustration shows the "hot Jupiter" exoplanet WASP-121b, which presents the best evidence yet of a stratosphere on an exoplanet.

Credit: Engine House VFX, At-Bristol Science Centre, University of Exeter

A huge, superhot alien planet has a stratrosphere, like Earth does, a new study suggests.

"This result is exciting because it shows that a common trait of most of the atmospheres in our solar system — a warm stratosphere — also can be found in exoplanet atmospheres," study co-author Mark Marley, of NASA's Ames Research Center in California's Silicon Valley, said in a statement.

"We can now compare processes in exoplanet atmospheres with the same processes that happen under different sets of conditions in our own solar system," Marley added. [Gallery: The Strangest Alien Planets]

The research team, led by Thomas Evans of the University of Exeter in England, detected spectral signatures of water molecules in the atmosphere of WASP-121b, a gas giant that lies about 880 light-years from Earth. These signatures indicate that the temperature of the upper layer of the planet's atmosphere increases with the distance from the planet's surface. In the bottom layer of the atmosphere, the troposphere, the temperature decreases with altitude, study team members said.

WASP-121b lies incredibly close to its host star, completing one orbit every 1.3 days. The planet is a "hot Jupiter"; temperatures at the top of its atmosphere reach a sizzling 4,500 degrees Fahrenheit (2,500 degrees Celsius), researchers said.

"The question [of] whether stratospheres do or do not form in hot Jupiters has been one of the major outstanding questions in exoplanet research since at least the early 2000s," Evans told Space.com. "Currently, our understanding of exoplanet atmospheres is pretty basic and limited. Every new piece of information that we are able to get represents a significant step forward."

The top of WASP-121b's atmosphere is heated to a blazing 4,600 degrees Fahrenheit (2,500 Celsius), hot enough to boil some metals.

Credit: G. Bacon (STSci)/NASA/ESA


The discovery is also significant because it shows that atmospheres of distant exoplanets can be analyzed in detail, said Kevin Heng of the University of Bern in Switzerland, who is not a member of the study team.

"This is an important technical milestone on the road to a final goal that we all agree on, and the goal is that, in the future, we can apply the very same techniques to study atmospheres of Earth-like exoplanets," Heng told Space.com. "We would like to measure transits of Earth-like planets. We would like to figure out what type of molecules are in the atmospheres, and after we do that, we would like to take the final very big step, which is to see whether these molecular signatures could indicate the presence of life."

Available technology does not yet allow such work with small, rocky exoplanets, researchers said.

"We are focusing on these big gas giants that are heated to very high temperatures due to the close proximity of their stars simply because they are the easiest to study with the current technology," Evans said. "We are just trying to understand as much about their fundamental properties as possible and refine our knowledge, and, hopefully in the decades to come, we can start pushing towards smaller and cooler planets."

WASP-121b is nearly twice the size of Jupiter. The exoplanet transits, or crosses the face of, its host star from Earth's perspective. Evans and his team were able to observe those transits using an infrared spectrograph aboard NASA's Hubble Space Telescope.

"By looking at the difference in the brightness of the system for when the planet was not behind the star and when it was behind the star, we were able to work out the brightness and the spectrum of the planet itself," Evans said. "We measured the spectrum of the planet using this method at a wavelength range which is very sensitive to the spectral signature of water molecules."

The team observed signatures of glowing water molecules, which indicated that WASP-121b's atmospheric temperatures increase with altitude, Evans said. If the temperature decreased with altitude, infrared radiation would at some point pass through a region of cooler water-gas, which would absorb the part of the spectrum responsible for the glowing effect, he explained.

There have been hints of stratospheres detected on other hot Jupiters, but the new results are the most convincing such evidence to date, Evans said.

"It's the first time that it has been done clearly for an exoplanet atmosphere, and that's why it's the strongest evidence to date for an exoplanet stratosphere," he said.

He added that researchers might be able to move closer to studying more Earth-like planets with the arrival of next-generation observatories such as NASA's James Webb Space Telescope and big ground-based observatories such as the Giant Magellan Telescope (GMT), the European Extremely Large Telescope (E-ELT) and the Thirty Meter Telescope (TMT). JWST is scheduled to launch late next year, and GMT, E-ELT and TMT are expected to come online in the early to mid-2020s.

The new study was published online Wednesday (Aug. 2) in the journal Nature.

Follow us @Spacedotcom, Facebook or Google+. Originally published on Space.com.

Ancient Asteroid Family Dates Back to Our Solar System's Early Days

Ancient Asteroid Family Dates Back to Our Solar System's Early Days:

Researchers have found that a family of asteroids that dates back to the solar system's early days. Here is an artist's concept of a broken-up asteroid. The leftover building blocks of the solar system, called planetesimals, were similarly fragmented, and they drifted apart over time.

Credit: NASA/JPL-Caltech

A newfound ancient family of asteroids is nearly as old as the solar system, and it could shed light on how Earth and the other planets formed, a new study finds.

In the early days of the solar system, rocky material clumped together into bodies known as planetesimals. Some of these planetesimals collected to form the planets, while others mostly settled in the main belt of asteroids, between Mars and Jupiter.

Understanding what the planetesimals were originally like could yield insights into how the asteroids and planets formed, the new study's researchers told Space.com. However, over billions of years, countless collisions have shattered nearly every ancient planetesimal into asteroids, they added. These fragments have drifted apart over time, making it difficult to identify families of related asteroids and learn about the planetesimals they came from. [The Asteroid Belt Explained: Space Rocks by the Millions (Infographic)]

Now, scientists have identified a previously unknown family of darkly colored asteroids that is "the oldest known family in the main belt," said study lead author Marco Delbo, an astrophysicist at the University of the Côte d'Azur in Nice, France.

This discovery came as part of research into the inner portion of the main belt. "Most of the asteroids and meteorites that hit the Earth come from this source region," Delbo told Space.com. "Also, we and many other colleagues wanted to trace the asteroid Bennu, the target of NASA's OSIRIS-REx sample return space mission, back to its origin in the main belt and possibly to a parent asteroid."

The scientists used a computer model to look for v-shaped groups of asteroids. This shape is what one would expect from a single-parent body that fragmented into pieces and dispersed over time, the researchers said.

This newfound asteroid family consists of rocks averaging 7.15 miles (11.5 kilometers) in diameter that are found across the entire inner part of the main belt. This family has 108 members of which the researchers are certain, the largest of which is asteroid 282 Clorinde, which is about 26.1 miles (42 km) wide.

"There are other asteroids in the region that could also be part of our primordial family," Delbo said.
"The largest of these is 51 Nemausa, with a diameter of 138 km (85.75 miles)."

Based on the asteroid family's size and shape, the researchers estimated that it is about 4 billion years old. In comparison, the solar system was born about 4.6 billion years ago. One other asteroid family potentially as old as this one is found among the Hildas, a group of asteroids located beyond the main belt, nearly as far away from the sun as Jupiter is, Delbo said.

Asteroid families are usually named after their largest members, which are likely the parents of the rest of their families — smaller members are literally chips off the old blocks. However, "we would like to avoid to give a name to this family," Delbo said. This is because over the course of billion of years, gravitational tugs of war with the planets may have slung the parent of this family away from the rest of its members, he explained.

By analyzing this asteroid family and others, the scientists estimated the original planetesimals were all larger than 15.5 miles (35 km) wide. This supports the traditional view of asteroid formation, which says that most were born as fragments of large chunks of rock, in contrast to some recent models, which suggest that planetesimals were much smaller chunks of rock, Delbo said.

"The almost 1 million asteroids that we see in the main belt can be linked to a few progenitors — those that were born big," Delbo said.

The scientists said they plan to use their new method to find asteroid families in other areas of the main belt. "There are more families yet to be discovered," Delbo said. This research could go on to reveal "precious information about the orbital and mass distribution of planetesimals at the time when the planets were forming," he said.

The scientists detailed their findings online today in the journal Science.

Follow Charles Q. Choi on Twitter @cqchoi. Follow us @Spacedotcom, Facebook and Google+. Original article on Space.com.

JUPITER - Hubble Eyes Stratosphere Around a Very Hot, Watery Jupiter!

Hubble Eyes Stratosphere Around a Very Hot, Watery Jupiter!:

Extra-solar planet discoveries have been exploding in recent years. In fact, as of Aug. 1st, 2017, astronomers have identified 3,639 exoplanets in 2,729 planetary systems and 612 multiple planetary systems. And while the majority of these have been discovered by Kepler – which has detected a total of 5,017 candidates and confirmed the existence of 2,494 exoplanets since 2009 – other instruments have played an important role in these discoveries as well.

This includes the Hubble Space Telescope, which in recent years has been dedicated to the detection of atmospheres around distant planets. Most recently, it was used in a survey that produced the strongest evidence to date for the existence of a stratosphere – a layer of atmosphere in which temperature increases with altitude – around a gas giant located about 900 light-years from our Solar System.

The study, titled “An ultrahot gas-giant exoplanet with a stratosphere“, recently appeared in the journal Nature. Led by Thomas Evans, a Research Fellow from the Astrophysics Group at the University of Exeter, the team relied on data provided by NASA’s Hubble Space Telescope to study a planet known as WASP-121b, a gas giant that orbits a yellow-white star that is slightly larger than our own.

The top of the planet’s atmosphere is heated to a blazing 2,500 °C (4,600 °F), hot enough to boil some metals. Credit: NASA/ESA/G. Bacon (STSci)

The planet itself has roughly 1.2 times the mass of Jupiter, has a radius that is about 1.9 times that of Jupiter, and has an orbital period of just 1.3 days. This is due to its close proximity to its sun, which makes it a particularly “Hot Jupiter”. In fact, if this exoplanet were any closer to its star, it is estimated that WASP-121’s gravity would begin to tear it apart.

It is also this close proximity that super-heats the planet’s atmosphere, driving temperatures up to 2,500 °C (4,600 °F). As Mark Marley, a researcher with NASA’s Ames Research Center and a co-author on the study, indicated in a NASA press statement:

“This result is exciting because it shows that a common trait of most of the atmospheres in our solar system — a warm stratosphere — also can be found in exoplanet atmospheres. We can now compare processes in exoplanet atmospheres with the same processes that happen under different sets of conditions in our own solar system.”

Whereas Hubble has found possible signs of stratospheres around WASP-33b and other hot Jupiters in the past, this new study presents the strongest evidence to date for the existence of an exoplanet stratosphere. The reason for this has to do with the spectrographic data obtained by Hubble of WASP-121b’s atmosphere, which indicated the presence of water vapor – which is a first as far as hot-Jupiter’s are concerned.



As Tom Evans – also a Research Fellow at the University of Exeter and the lead author on the paper – explained, these findings confirmed something that astronomers have suspected for some time. “Theoretical models have suggested stratospheres may define a distinct class of ultra-hot planets, with important implications for their atmospheric physics and chemistry,” he said. “Our observations support this picture.”

To study WASP-121b’s stratosphere, the team relied on spectroscopic data gathered by Hubble’s Wide Field Camera 3. After analyzing the different wavelengths that were part of WASP-121b’s light cure, they noted that certain  wavelengths were glowing rather brightly in the infrared band. This, they concluded, was due to the presence of water vapor at the top of the planet’s atmosphere.

“The emission of light from water means the temperature is increasing with height,” Tiffany Kataria, one of the co-authors on the study from NASA’s Jet Propulsion Laboratory, said. “We’re excited to explore at what longitudes this behavior persists with upcoming Hubble observations.”

Beyond being the most convincing case so far of an exoplanet having a stratosphere, WASP-121b is also interesting because of just how hot this hot Jupiter is. Based on their data, the team concluded that temperatures in the atmosphere increased with altitude – a defining characteristic of a stratosphere. In Earth’s stratosphere, this process is driven by ozone, which traps the Sun’s ultraviolet light and raises the temperature of the surrounding molecules.

Artist’s concept of “hot Jupiter” exoplanet, a gas giant that orbits very close to its star. Credit: NASA/JPL-Caltech)

However, the temperature of Earth’s stratosphere does not exceed 270 K (-3°C; 26.6°F). When one considers other Solar Planets that also have stratosphere’s – like Saturn’s moon Titan, which experiences heating due to the interaction of solar radiation, energetic particles and methane – temperatures don’t change by more than 56 °C (100 °F). But in the case of WASP-121b, temperatures in the stratosphere increase by about 560 °C (1,000 °F).

Not even Venus, the hottest planet in the Solar System, can compete with that! On Earth’s “Sister Planet”, temperatures remain steady at about 735 K (462 °C; 863 °F), which is hot enough to melt lead. But on WASP-121b,  temperatures reach over four times as high! This means the planet’s atmosphere is hot enough to melt stainless steel and other metals – like beryllium, platinum and zirconium.

At present, scientists do not now what chemicals are driving this temperature increase. Some possibilities have been suggested though, such as vanadium oxide and titanium oxide. Not only are these compounds believed to be common to brown dwarfs (aka. “failed stars”, which have much in common with gas giants), they also require the hottest temperatures possible in order to keep them in a gaseous state.

In any case, this distant gas giant has proven to be an interesting case study. In the future, research into this and other “super-hot Jupiters” is likely to challenge and expand our current understanding of how atmospheric forms and behave over time.



Further Reading: NASA, Nature

The post Hubble Eyes Stratosphere Around a Very Hot, Watery Jupiter! appeared first on Universe Today.

SUPERNOVA - Rebel Supernova Formed in 'Heavy Metal' Galaxy

Rebel Supernova Formed in 'Heavy Metal' Galaxy:

An artist's impression of SN 2017egm showing the superluminous supernova's power source. The ultrabright explosion came when a massive star collapsed to form a rapidly-spinning neutron star with an extremely strong magnetic field, called a magnetar. Debris from the supernova is in blue, and the magnetar is in red.

Credit: M. Weiss/CfA

The most powerful exploding stars are popping up in unexpected places, new research indicates. It turns out that these superbright "rebel" supernovas can form in "heavy metal" areas, using elements heavier than hydrogen and helium, scientists said in the new study.

Supernovas happen when huge stars run out of fuel and collapse, creating an explosion that can briefly outshine their host galaxy. Thousands of supernovas have happened in the past decade, but only about 50 of them were "superluminous," meaning they were 100 times brighter than usual supernovas.

New research zeroes in on one supernova, called SN 2017egm, which exploded May 23 within view of the European Space Agency's Gaia satellite, which monitors star positions. If it had exploded in the Milky Way, it would have appeared as bright as the full moon does from Earth, researchers said in a statement. [Supernova Photos: Great Images of Star Explosions]

In fact, SN 2017egm was not only superluminous, but superclose: At just 420 million light-years away, it was three times closer than any other observed supernova of its type.

More strangely, the supernova exploded in a spiral galaxy with a high concentration of elements heavier than hydrogen and helium. (These elements are called "metals" in astronomy.) Before this, researchers had found superluminous supernovas in dwarf galaxies, which have low metal content, according to the statement.

This work marks the first time astronomers have identified a superluminous supernova that exploded in a large spiral galaxy, and in a metal-rich area. So when it comes to forming these explosions, a lack of metals may not be as important as astronomers had thought.

"Superluminous supernovas were already the rock stars of the supernova world," Matt Nicholl, lead author of the study and an astronomer at the Harvard-Smithsonian Center for Astrophysics in Cambridge, Massachusetts, said in the statement. "We now know that some of them like heavy metal, so to speak, and explode in galaxies like our own Milky Way."

The researchers also investigated what makes SN 2017egm so bright. They concluded that the supernova may be powered by a rapidly spinning dead star called a magnetar. Such ultradense, spinning neutron stars created by supernovas could continue to generate magnetic power that would heat up the expanding gas left over from the supernova.

SN 2017egm shares magnetar properties with other superluminous supernovas, but the researchers noted that the newly discovered supernova does have some differences.

For example, SN 2017egm might have ejected less mass than its supernova counterparts because its massive star might have shed mass before exploding. Also, the spin rate of SN 2017egm's magnetar may be slower than usual.

The supernova is currently invisible to astronomers because it is too close to the sun, but it will re-emerge on Sept. 16 after more than two months of obscurity.

"This should break all records for how long a superluminous supernova can be followed," Raffaella Margutti, study co-author and an astronomer at Northwestern University, said in the statement. "I'm excited to see what other surprises this object has in store for us."

The research was accepted for publication in The Astrophysical Journal Letters, and it is available online at arXiv.org. Nicholl's team studied the supernova on June 18 with the 60-inch (152 centimeters) telescope at the Smithsonian Astrophysical Observatory's Fred Lawrence Whipple Observatory in Arizona.

Follow us @Spacedotcom, Facebook and Google+. Original article on Space.com.

Cameras on NASA Exoplanet Spacecraft Slightly Out of Focus

Cameras on NASA Exoplanet Spacecraft Slightly Out of Focus:

NASA's Transiting Exoplanet Survey Satellite will fly in a unique highly-elliptical orbit to search for exoplanets around the nearest and brightest stars.

Credit: NASA

WASHINGTON — Cameras recently installed on a NASA spacecraft designed to look for nearby exoplanets will be slightly out of focus once launched, but the agency said that will not affect the mission's science.

NASA confirmed July 26 that the focus of the four cameras on the Transiting Exoplanet Survey Satellite (TESS) spacecraft will drift when the spacecraft cools to operating temperatures after launch next March. The problem was noticed in recent tests when the cameras were chilled to approximately minus 103 degrees Fahrenheit (minus 75 degrees Celsius).

"Recent tests show the cameras on TESS are slightly out of focus when placed in the cold temperatures of space where it will be operating," NASA spokesperson Felicia Chou said in response to a SpaceNews inquiry. "After a thorough engineering evaluation, NASA has concluded TESS can fully accomplish its science mission with the cameras as they are, and will proceed with current integration activities." [Gallery: The Strangest Alien Planets]

Chou added July 28 that the out-of-focus area is limited to the outer edges of the image, and that "recent testing shows that the camera focus towards the image center is better than originally designed."

The problem with the TESS cameras came up during a July 24 meeting of the NASA Advisory Council science committee in Hampton, Virginia. Alan Boss, an astronomer with the Carnegie Institution, brought up the issue in a summary of a meeting of the Astrophysics Advisory Committee, of which he is a member.

"That could have some big effects on the photometry," he said of the focus problem. "This is certainly a concern for the folks who know a lot about photometry."

TESS will use those cameras to monitor the brightness of the nearest and brightest stars in the sky, an approach similar to that used by Kepler, a NASA spacecraft developed originally to monitor one specific region of the sky. Both spacecraft are designed to look for minute, periodic dips in brightness of those stars as planets pass in front of, or transit, them.

In a photo posted to Twitter July 25, technicians pose with the four cameras that will be installed on the TESS spacecraft.

Credit: NASA



Chou said that since TESS is designed to conduct photometry, measuring the brightness of the stars in its field of view, "resolution is less important compared to imaging missions like Hubble." However, astronomers are concerned that there will be some loss of sensitivity because light from the stars will be spread out onto a slightly larger area of the detector.

"The question is how much science degradation will there be in the results," Boss said. "The TESS team thinks there will be a 10 percent cut in terms of the number of planets that they expect to be able to detect."

Despite the reduction, Boss said TESS scientists believe they will still be able to meet the mission's primary science requirements, and thus there is no need to fix the cameras. The four cameras were attached this week to a plate that will later be installed on the spacecraft, which is being assembled by Orbital ATK.

"There will be some loss of science, and we just want to know more about it," Boss said. That includes anything the project can do in software, or even mechanical fixes to the spacecraft, to compensate for the focus problem.

NASA has not disclosed the cause of the focus problem, but Boss said it may be due to crystallization of the glue used to bond the detector arrays in place. He said project engineers didn't expect the focus to continue to drift after the temperature stabilized.

Chou said the project will continue to monitor the problem. "Should further testing reveal the cameras are unable to complete the mission, NASA will revisit the decision and determine the steps moving forward," she said.

TESS is scheduled to launch no earlier than March 2018 on a SpaceX Falcon 9 rocket. That launch was previously planned for late 2017 but postponed by delays in SpaceX's launch schedule and the NASA launch certification process.

TESS will operate in a unique orbit that takes it between 67,000 miles and 232,000 miles (108,000 and 373,000 kilometers) from Earth. The orbit is particularly stable, thus minimizing the maneuvers the spacecraft has to perform to maintain it.

The spacecraft will have a two-year primary mission, and scientists expect it to detect thousands of exoplanets, including dozens the size of the Earth. Astronomers plan to follow up some of the most promising discoveries with the James Webb Space Telescope and the Wide Field Infrared Survey Telescope.

This story was provided by SpaceNews, dedicated to covering all aspects of the space industry.

ALIENS ? UFOS ? Want to Protect Earth from Aliens? NASA Is Hiring

Want to Protect Earth from Aliens? NASA Is Hiring:

Mars as seen by NASA’s Viking 1 orbiter.

Credit: NASA/JPL

If you've always dreamed of helping keep Earth safe from alien invaders, your ship may have just come in.

NASA is looking to hire a planetary protection officer, a person who will lead the agency's efforts to keep its spacecraft and astronauts from contaminating worlds with life-forms that don't belong there.

NASA officials have stressed that keeping Earth clean — of alien microbes that could arrive here in a sample-return capsule, for example — is the highest priority, but the responsibility applies to all celestial objects that agency spacecraft visit.

"NASA maintains policies for planetary protection applicable to all spaceflight missions that may intentionally or unintentionally carry Earth organisms and organic constituents to the planets or other solar system bodies, and any mission employing spacecraft which are intended to return to Earth and its biosphere with samples from extraterrestrial targets of exploration," NASA officials wrote in a job description. "This policy is based on federal requirements and international treaties and agreements."

So the job checks the making-a-difference box. The pay is good, too; the stated salary range is $124,406 to $187,000. And if you're after a challenge, you'll almost certainly get it.

The topic of planetary protection is generating more and more discussion these days as NASA works on getting (microbe-laden) astronauts to Mars and sending robotic probes to potentially habitable worlds, such as Jupiter's ocean-harboring moon Europa. (The agency is scheduled to launch a Europa flyby mission in the 2020s, and Congress has instructed NASA to put a lander down on the moon's icy surface as well.)

Such plans have spurred debate within the spaceflight community, with some exploration advocates stressing that planetary-protection concerns could hinder the effort to put boots on Mars and hunt for life on the Red Planet.

Still interested? You have until Aug. 14 to apply (which you can do here).

This is not a newly created job; Cassie Conley has been NASA's planetary protection officer for several years now. The new posting is a result of relocating the position to NASA's Office of Safety and Mission Assurance, Conley told Business Insider. She did not indicate whether she plans to reapply, Business Insider reported.

Follow Mike Wall on Twitter @michaeldwall and Google+. Follow us @Spacedotcom, Facebook or Google+. Originally published on Space.com.

Company Loses Contact With Communications Satellite While Changing Orbit

Company Loses Contact With Communications Satellite While Changing Orbit:

AGI's Commercial Space Operations Center (ComSpOC) is tracking EchoStar-3 drifting at a rate of 0.1 degree per day in geostationary orbit.

Credit: AGI

WASHINGTON — A 20-year old satellite in fleet operator EchoStar's constellation is drifting after an anomaly the company said has crippled communications.

Englewood, Colorado-based EchoStar said EchoStar-3 "experienced an anomaly of unknown origin" during a relocation maneuver last week "that has caused communications with the satellite to be interrupted and intermittent."

Built by Lockheed Martin and launched in 1997 on an Atlas 2AS rocket, the satellite was operating five years past its design life, and had been placed in a fuel-saving inclined orbit for the past three-plus years, EchoStar said.

"EchoStar has received FCC authority for its current flight configuration, and we are working in cooperation with the satellite manufacturer to re-establish a reliable link in order to recover and retire the spacecraft," Derek de Bastos, EchoStar Satellite Services chief technology officer, said in an Aug. 2 statement. "In spite of the anomaly, we believe that the current EchoStar III orbit does not present a significant risk to the operating satellites in the geostationary arc."

ComSpOC, a commercial space situational awareness facility run by Exton, Pennsylvania-based Analytical Graphics Inc., has been tracking EchoStar-3 drifting westward along the geostationary arc at a rate of 0.1 degrees per day from 87.2 degrees west. The out-of-commission satellite follows SES's AMC-9 satellite that experienced an anomaly the weekend of June 17 that also set it drifting. AGI's ComSpOC tweeted July 7 that AMC-9 was drifting westward at roughly 0.2 degrees per day.

EchoStar said EchoStar-3 "is a fully depreciated, non-revenue generating asset." The satellite provided broadcast services in Ku-band.

This story was provided by SpaceNews, dedicated to covering all aspects of the space industry.

THE SUN - Sunrise Through the Solar Arrays

Sunrise Through the Solar Arrays: On July 26, 2017, a member of the Expedition 52 crew aboard the International Space Station took this photograph of one of the 16 sunrises they experience every day, as the orbiting laboratory travels around Earth. One of the solar panels that provides power to the station is seen in the upper left.

Original enclosures:

ECLIPSE - A Total Eclipse at the End of the World

A Total Eclipse at the End of the World:

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 July 30

A Total Eclipse at the End of the World

Image Credit & Copyright: Fred Bruenjes (moonglow.net)


Explanation: Would you go to the end of the world to see a total eclipse of the Sun? If you did, would you be surprised to find someone else there already? In 2003, the Sun, the Moon, Antarctica, and two photographers all lined up in Antarctica during an unusual total solar eclipse. Even given the extreme location, a group of enthusiastic eclipse chasers ventured near the bottom of the world to experience the surreal momentary disappearance of the Sun behind the Moon. One of the treasures collected was the featured picture -- a composite of four separate images digitally combined to realistically simulate how the adaptive human eye saw the eclipse. As the image was taken, both the Moon and the Sun peeked together over an Antarctic ridge. In the sudden darkness, the magnificent corona of the Sun became visible around the Moon. Quite by accident, another photographer was caught in one of the images checking his video camera. Visible to his left are an equipment bag and a collapsible chair. A more easily visible solar eclipse will occur in about three weeks and be visible from the USA.

Tomorrow's picture: surfing pluto

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PLUTO - Pluto Flyover from New Horizons

Pluto Flyover from New Horizons:

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 July 31


Pluto Flyover from New Horizons

Credit: NASA, JHUAPL, SwRI, P. Schenk & J. Blackwell (LPI); Music Open Sea Morning by Puddle of Infinity


Explanation: What if you could fly over Pluto -- what might you see? The New Horizons spacecraft did just this in 2015 July as it shot past the distant world at a speed of about 80,000 kilometers per hour. Recently, many images from this spectacular passage have been color enhanced, vertically scaled, and digitally combined into the featured two-minute time-lapse video. As your journey begins, light dawns on mountains thought to be composed of water ice but colored by frozen nitrogen. Soon, to your right, you see a flat sea of mostly solid nitrogen that has segmented into strange polygons that are thought to have bubbled up from a comparatively warm interior. Craters and ice mountains are common sights below. The video dims and ends over terrain dubbed bladed because it shows 500-meter high ridges separated by kilometer-sized gaps. Although the robotic New Horizons spacecraft has too much momentum ever to return to Pluto, it has now been targeted at Kuiper Belt object 2014 MU 69, which it should shoot past on New Year's Day 2019.

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Tomorrow's picture: sand shower

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Authors & editors: Robert Nemiroff (MTU) & Jerry Bonnell (UMCP)
NASA Official: Phillip Newman Specific rights apply.
NASA Web Privacy Policy and Important Notices
A service of: ASD at NASA / GSFC
& Michigan Tech. U.

METEORS IN TURKEY - Perseid Meteors over Turkey

Perseid Meteors over Turkey:

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 1

Explanation: The Perseid Meteor Shower, usually the best meteor shower of the year, will peak late next week. A person watching a clear sky from a dark location might see a bright meteor every minute. These meteors are actually specks of rock that have broken off Comet Swift-Tuttle and continued to orbit the Sun until they vaporize in Earth's atmosphere. The featured composite image shows a outburst of Perseids as they appeared over Turkey during last year's meteor shower. Enough meteors were captured to trace the shower's radiant back to the constellation of Perseus on the far left. The tail-end of the Perseids will still be going during the total solar eclipse on August 21, creating a rare opportunity for some lucky astrophotographers to image a Perseid meteor during the day.

LUNAR ECLIPSE - A Partial Lunar Eclipse Ushers in Eclipse Season

A Partial Lunar Eclipse Ushers in Eclipse Season:

The partial lunar eclipse of June 4th, 2012. Credit: Dave Dickinson

Live on the wrong continent to witness the August 21^st total solar eclipse? Well… celestial mechanics has a little consolation prize for Old World observers, with a partial lunar eclipse on the night of Monday into Tuesday, August 7/8^th.

A partial lunar eclipse occurs when the Moon just nicks the inner dark core of the Earth’s shadow, known as the umbra. This eclipse is centered on the Indian Ocean region, with the event occurring at moonrise for the United Kingdom, Europe and western Africa and moonset/sunrise for New Zealand and Japan. Western Australia, southern Asia and eastern Africa will see the entire eclipse.

The path of the Moon through the Earth’s shadow Monday night. Credit: adapted from NASA/GSFC/Fred Espenak

The penumbral phase of the eclipse begins on August 7^th at 15:50 Universal Time (UT), though you probably won’t notice a slight tea colored shading on the face of the Moon until about half an hour in. The partial phases begin at 17:23 UT, when the ragged edge of the umbra becomes apparent on the southeastern limb of the Moon. The deepest partial eclipse occurs at 18:22 UT with 25% of the Moon submerged in the umbra. Partial phase lasts 116 minutes in duration, and the entire eclipse is about five hours long.

The viewing prospects for the partial lunar eclipse. Credit: NASA/GSFC/Fred Espenak.

This also marks the start of the second and final eclipse season for 2017. Four eclipses occur this year: a penumbral lunar eclipse and annular solar eclipse this past February, and this month’s partial lunar and total solar eclipse.

Eclipses always occur in pairs, or very rarely triplets with an alternating lunar-solar pattern. This is because the tilt of the Moon’s orbit is inclined five degrees relative to the ecliptic, the plane of the Earth’s orbit around the Sun. The Moon therefore misses the 30′ wide disk of the Sun and the 80′ – 85′ wide inner shadow of the Earth on most passes.

The partial lunar eclipse of April 26th, 2013. Image credit and copyright: Henna Khan

Fun fact: at the Moon’s 240,000 mile distance from the Earth, the ratio of the apparent size of the Moon and the shadow is approximately equivalent to a basketball and a hoop.

When celestial bodies come into alignment, however, things can get interesting. For an eclipse to occur, the nodes – the point where the Moon’s orbit intersects the ecliptic – need to align with the position of the Moon and the Sun. There are two nodes, one descending with the Moon crossing the ecliptic from north to south, and one ascending. The time it takes for the Moon to return to the same node (27.2 days) is a draconitic month. Moreover, the nodes are moving around the Earth due to drag on the Moon’s orbit mainly by the Sun, and move all the way around the zodiac once every 18.6 years.

Got all that? Let’s put it into practice with this month’s eclipses. First, the Moon crosses its descending node at 10:56 UT on August 8th, just over 16 hours after Monday’s partial eclipse. Two weeks later, however, the Moon crosses ascending node just under eight hours from the central conjunction with the Sun, and a total solar eclipse occurs.

Tales of the Saros

The August 7^th lunar eclipse is member number 62 of the 83 lunar eclipses in saros series 119, which started on October 14^th, 935 AD and will end with a final shallow penumbral eclipse on March 25^th, 2396 AD. If you witnessed the lunar eclipse of July 28^th, 1999, then you saw the last lunar eclipse in the same saros. Saros 119 produced its last total lunar eclipse on June 15^th, 1927.

The next lunar eclipse, a total occurs on January 31^st, 2018, favoring the Pacific rim regions.

Partial lunar eclipses have occasionally work their way into history, usually as bad omens. One famous example is the partial lunar eclipse of May 22^nd, 1453 which preceded the Fall of Constantinople to the Ottoman Turks by a week. Apparently, a long standing legend claimed that a lunar eclipse would be the harbinger of the fall of Byzantium, and the partially eclipsed Moon rising over the besieged city ramparts seemed to fulfill the prophecy.

In our more enlightened age, we can simply enjoy Monday’s partial lunar eclipse as a fine celestial spectacle. You don’t need any special equipment to enjoy a lunar eclipse, just a view from the correct Moonward facing hemisphere of the Earth, and reasonably clear skies.

See the curve of the Earth’s shadow? This is one of the very few times that you can see that the Earth is indeed round (sorry, Flat Earthers) with your own eyes. And this curve is true for observers watching the Moon on the horizon, or high overhead near the zenith.

This month’s lunar eclipse occurs in the astronomical constellation of Capricornus. The Moon will also occult the +5^th magnitude star 29 Capricorni for southern India, Madagascar and South Africa shortly after the eclipse.

The viewing footprint for the 29 Capricorni occultation shortly after the eclipse. Credit: Occult 4.2.

Finally, anyone out there planning on carrying the partial lunar eclipse live, let us know… curiously, even Slooh seems to be sitting this one out.

Update: we have one possible broadcast, via Shahrin Ahmad (@shahgazer on Twitter). Updates to follow!

The final eclipse season for 2017 is now underway, starting Monday night. Nothing is more certain in this Universe than death, taxes and celestial mechanics, as the path of the Moon now sends it headlong to its August 21^st destiny and the Great American Total Solar Eclipse.

-We’ll be posting on Universe Today once more pre-total solar eclipse one week prior, with weather predictions, solar and sunspot activity and prospects for viewing the eclipse from Earth and space and more!

-Read more about this year’s eclipses in our 2017 Guide to 101 Astronomical Events.

-Eclipse… science fiction? Read our original eclipse-fueled tales Exeligmos, Shadowfall, Peak Season and more!

The post A Partial Lunar Eclipse Ushers in Eclipse Season appeared first on Universe Today.

Kepler Spots the First Exomoon Candidate 4000 Light Years From Earth

Kepler Spots the First Exomoon Candidate 4000 Light Years From Earth:

Ever since it was deployed in March of 2009, the Kepler mission has detected thousands of extra-solar planet candidates. In fact, between 2009 and 2012, it detected a total of 4,496 candidates, and confirmed the existence of 2,337 exoplanets. Even after two of its reaction wheels failed, the spacecraft still managed to turn up distant planets as part of its K2 mission, accounting for another 521 candidates and confirming 157.

However, according to a new study conducted by a pair of researches from Columbia University and a citizen scientist, Kepler may also have also found evidence of an extra-solar moon. After sifting through data from hundreds of transits detected by the Kepler mission, the researchers found one instance where a transiting planet showed signs of having a satellite.

Their study – which recently published online under the title “HEK VI: On the Dearth of Galilean Analogs in Kepler and the Exomoon Candidate Kepler-1625b I” – was by led Alex Teachley, a graduate student at Columbia University and a Graduate Research Fellow with the National Science Foundation (NSF). He was joined by David Kippling, an Assistant Professor of Astronomy at Columbia University and the Principal Investigator of The Hunt for Exomoons with Kepler (HEK) project, and Allan Schmitt, a citizen scientist.

Artist’s impression of NASA’s Kepler spacecraft. Credit: NASA

For years, Dr. Kippling has been searching the Kepler database for evidence of exomoons, as part of the HEK. This is not surprising, considering the kinds of opportunities that exomoons present for scientific research. Within our Solar System, the study of natural satellites has revealed important things about the mechanisms that drive early and late planet formation, and moons possess interesting geological features that are commonly found on other bodies.

It is for this reason that extending that research to the hunt for exoplanets is seen as necessary. Already, exoplanet-hunting missions like Kepler have turned up a wealth of planets that challenge conventional ideas about how planet formation and what kinds of planets are possible. The most noteworthy example are gas giants that have observed orbiting very close to their stars (aka. “Hot Jupiters”).

As such, the study of exomoons could yield valuable information about what kinds of satellites are possible, and whether or not our own moons are typical. As Teachey told Universe Today via email:

“Exomoons could tell us a lot about the formation of our Solar System, and other star systems. We see moons in our Solar System, but are they common elsewhere? We tend to think so, but we can’t know for sure until we actually see them. But it’s an important question because, if we find out there aren’t very many moons out there, it suggests maybe something unusual was going on in our Solar System in the early days, and that could have major implications for how life arose on the Earth. In other words, is the history of our Solar System common across the galaxy, or do we have a very unusual origin story? And what does that say about the chances of life arising here? Exomoons stand to offer us clues to answering these questions.”

A montage of some of the potentially-habitable moons in our Solar System. From top to bottom, left to right, these include Europa, Enceladus, TItan and Ceres. Credit: NASA/JPL

What’s more, many moons in the Solar System – including Europa, Ganymede, Enceladus and Titan – are thought to host life in their interiors. This is due to the fact that these bodies have steady supplies of volatiles (such as nitrogen, water, carbon dioxide, ammonia, hydrogen, methane and sulfur dioxide) and possess internal heating mechanisms that could provide the necessary energy to power biological processes.

Here too, the study of exomoons presents interesting possibilities, such as whether or not they may be habitable or even Earth-like. For these and other reasons, astronomers want to see if the planets that have been confirmed in distant star systems have systems of moons and what conditions are like on them. But as Teachey indicated, the search for exomoons presents a number of challenges compared to exoplanet-hunting:

“Moons are difficult to find because 1) we expect them to be quite small most of the time, meaning the transit signal will be quite weak to begin with, and 2) every time a planet transits, the moon will show up in a different place. This makes them more difficult to detect in the data, and modeling the transit events is significantly more computationally expensive. But our work leverages the moons showing up in different places by taking the time-averaged signal across many different transit events, and even across many different exoplanetary systems. If the moons are there, they will in effect carve out a signal on either side of the planetary transit over time. Then it’s a matter of modeling this signal and understanding what it means in terms of moon size and occurrence rate.”

To locate signs of exomoons, Teachey and his colleagues searched through the Kepler database and analyzed the transits of 284 exoplanet candidates in front of their respective stars. These planets ranged in size from being Earth-like to Jupiter-like in diameter, and orbited their stars at a distance of between ~0.1 to 1.0 AU. They then modeled the light curve of the stars using the techniques of phase-folding and stacking.

An artist’s conception of a habitable exomoon. Credit: NASA

These techniques are commonly used by astronomers who monitor stars for dips in luminosity that are caused by the transits of planets (i.e. the transit method). As Headey explained, the process is quite similar:

“Basically we cut up the time-series data into equal pieces, each piece having one transit of the planet in the middle. And when we stack these pieces together we’re able to get a clearer picture of what the transit looks like… For the moon search we do essentially the same thing, only now we’re looking at the data outside the main planetary transit. Once we stack the data, we take the average values of all the data points within a certain time window and, if a moon is present, we ought to see some missing starlight there, which allows us to deduce its presence.”

What they found was a single candidate located in the Kepler-1625 system, a yellow star located about 4000 light years from Earth. Designated Kepler-1625B I, this moon orbits the large gas giant that is located within the star’s habitable zone, is 5.9 to 11.67 times the size of Earth, and orbits its star with a period of 287.4 days. This exomoon candidate, if it should be confirmed, will be the first exomoon ever discovered.

The team’s results (which await peer review) also demonstrated that large moons to be a rare occurrence in the inner regions of star systems (within 1 AU). This was something of a surprise, though Teachey acknowledges that it is consistent with recent theoretical work. According to what some recent studies suggest, large planets like Jupiter could lose their moons as they migrate inward.

If this should prove to be the case, then what Teachey and his colleagues witnessed could be seen as evidence of that process. It could also be an indication our current exoplanet-hunting missions may not be up to the task of detecting exomoons. In the coming years, next-generations missions are expected to provide more detailed analyses of distant stars and their planetary systems.

An artist’s conception of a distance exomoon blocking out a star’s light. Credit: Dan

However, as Teachey indicated, these too could be limited in terms of what they can detect, and new strategies may ultimately be needed:

“The rarity of moons in the inner regions of these star systems suggests that individual moons will remain difficult to find in the Kepler data, and upcoming missions like TESS, which should find lots of very short period planets, will also have a difficult time finding these moons. It’s likely the moons, which we still expect to be out there somewhere, reside in the outer regions of these star systems, much as they do in our Solar System. But these regions are much more difficult to probe, so we will have to get even more clever about how we look for these worlds with present and near-future datasets.”

In the meantime, we can certainly be exited about the fact that the first exomoon appears to have been discovered. While these results await peer review, confirmation of this moon will mean additional research opportunities for Kepler-1625 system. And the fact that this moon orbits within the star’s habitable zone could mean that it might be capable of sustaining life.

Hmm, a habitable moon orbiting a gas giant. Does that sound like something that might have come up in some science fiction movies?

Further Reading: arXiv



The post Kepler Spots the First Exomoon Candidate 4000 Light Years From Earth appeared first on Universe Today.

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