exoplanet Archives

July 4, 2013December 23, 2015 by Elizabeth Howell

When We Look For Life Beyond Earth, Let’s Consider Dying Planets: Study

Upper Geyser Basin region in Yellowstone National Park in Wyoming. A new study supposes the Earth will look like this after the sun heats up in a few billion years' time. Credit: Jack O’Malley-James

Bacteria. They’re so resilient that they can survive just about anywhere on Earth, even in spots of extreme hot or cold. As the sun warms up in the next few billion years, it’s likely that bacteria will be the only living creatures left on the planet, according to new research.

The study not only has implications for human survival — hopefully, our descendants will have left by then — but also our search for life on other planets. By predicting the signature these bacteria leave behind on the atmosphere, we can better hone our search for new planets, the study states.

Earth’s history shows that a species, just like an individual, can expect a lifetime that only lasts for so long. Sometimes a catastrophic event will wipe out a species, like what likely happened to the dinosaurs around 65 million years ago when a huge asteroid hit the Earth. Other times, it’s a slow process that is infinitesimal in an individual’s lifetime, but will eventually lead to changes that are unfriendly for life.

Thermophilic (heat-loving) bacteria may be among the last living creatures on Earth, the study suggests. Credit: Mark Amend / NOAA Photo Library

A computer model by Ph.D. astrobiologist Jack O’Malley James, who is at the University of St Andrews, suggests the first changes will take place in only a billion years. He will present his research at the ongoing Royal Astronomical Society national meeting at St. Andrews, Scotland, which is taking place this week.

“Increased evaporation rates and chemical reactions with rainwater will draw more and more carbon dioxide from the Earth’s atmosphere,” the Royal Astronomical Society stated. “The falling levels of CO2 [carbon dioxide] will lead to the disappearance of plants and animals and our home planet will become a world of microbes.”

Earth will then run out of oxygen and begin to dry out as temperatures rise and the oceans evaporate. Around two billion years in the future, there will be no oceans left.

The Sun in H-Alpha with close-up on a rushing prominence on 02-07-2013. Credit and copyright: John Chumack. — The sun, which allows Earth to be life-friendly right now, will warm up the planet and kill off most live forms in the next few billion years. Credit and copyright: John Chumack.

“The far-future Earth will be very hostile to life by this point,” O’Malley James stated. “All living things require liquid water, so any remaining life will be restricted to pockets of liquid water, perhaps at cooler, higher altitudes or in caves or underground.”

Life would disappear almost altogether in about 2.8 billion years.

Thankfully, humans plenty of time to figure out how to get around this problem. In the meantime, we can use the knowledge when seeking life beyond Earth.

Searches these days often focus on finding life like our own, which would leave “fingerprints” behind like oxygen and ozone.

“Life in the Earth’s far future will be very different to this, which means, to detect life like this on other planets we need to search for a whole new set of clues,” O’Malley James stated. “By the point at which all life disappears from the planet [surface], we’re left with a nitrogen:carbon-dioxide atmosphere, with methane being the only sign of active life”.

More information on this research is contained in an April 2013 article in the International Journal of Astrobiology.

Source: Royal Astronomical Society

June 26, 2013December 23, 2015 by Elizabeth Howell

Discovery! More Planets Found Orbiting In A Star Cluster

An artist's conception of an exoplanet transiting its home star. Credit: NASA's Goddard Space Flight Center

As Earthlings, we’re so used to thinking about planets being in simple orbits around a single star. But the Sun likely didn’t begin its life alone. It formed as part of a cluster of stars, all feeding from the same well of gas.

Could star clusters also host planets? Or do they have to wait for the little guys until the stars evolve and move further apart? Well, astronomers have actually just found planets — yes, two planets — orbiting Sun-like stars in a cluster 3,000 light-years from Earth.

These are the third and fourth star cluster planets yet discovered, but the first found “transiting” or passing across the face of their stars as seen from Earth. (The others were found through detecting gravitational wobbles in the star.)

This is no small feat for a planet to survive. In a telescope, a star cluster might look pretty benign, but up close it’s pretty darn harsh. A press release about the discovery used a lot of words like “strong radiation”, “harsh stellar winds” and “stripping planet-forming materials” in a description of what NGC 6811 would feel like.

An artist's conception of a planet in a star cluster. Credit: Michael Bachofner — An artist’s conception of a planet in a star cluster. Credit: Michael Bachofner

“Old clusters represent a stellar environment much different than the birthplace of the Sun and other planet-hosting field stars,” stated lead author Soren Meibom of the Harvard-Smithsonian Center for Astrophysics.

“We thought maybe planets couldn’t easily form and survive in the stressful environments of dense clusters, in part because for a long time we couldn’t find them.”

The find, as you would expect, comes from the prolific planet-hunting NASA Kepler spacecraft that is now battling problems with pointing in the right direction. Although the telescope is in the penalty box, there still are reams of data waiting to be analyzed and released.

The planets are known as Kepler-66b and Kepler-67b, and are both approaching the size of Neptune (which is four times the size of Earth). Their parent cluster, NGC 6811, is one billion years old. Astronomers are still puzzled as to how these little worlds survived for so long.

“Highly energetic phenomena including explosions, outflows and winds often associated with massive stars would have been common in the young cluster,” stated the journal paper in Nature.

“The degree to which the formation and evolution of planets is influenced by a such a dense and dynamically and radiatively hostile environment is not well understood, either observationally or theoretically.”

Check out the entire study in the latest edition of Nature.

Source: Harvard-Smithsonian Center for Astrophysics

June 3, 2013December 23, 2015 by Elizabeth Howell

Smile! This Could Be The Lightest Alien Planet Ever Captured On Camera

Planet HD95086 b is shown at lower left in this picture. Astronomers blocked out the light of the star (center) to image the exoplanet. The blue circle represents the equivalent orbit of Neptune in this star system. Credit: ESO/J. Rameau

We’ve found hundreds of planets outside the solar system, but taking a picture of one is still something quite special. The light of the parent star tends to greatly overwhelm the faint light of the alien planet. (So usually we learn about planets by tracking the effects each planet has on its star, like dimming light when it passes in front or making the star slightly wobble.)

This picture (above) shows HD95086 b, which astronomers believe is one of only about a dozen exoplanets ever imaged. It’s 300 light-years from Earth. The planet candidate is about four to five times the mass of Jupiter and orbiting a very young star that is probably only 10 million to 17 million years old. That’s a baby compared to our own solar system, estimated at 4.5 billion years old.

We still have a lot to learn about this object (and the observations from the Very Large Telescope will need to be confirmed independently), but so far astronomers say they figure that planet formed in the gas and dust surrounding star HD 95086. But the planet is actually very far away from the star now, about twice the distance as the Sun-Neptune orbital span in our own solar system.

The Very Large Telescope (VLT) at ESO's Cerro Paranal observing site. Located in the Atacama Desert of Chile, the site is over 2600 metres above sea level, providing incredibly dry, dark viewing conditions. The VLT is the worldâ??s most advanced optical instrument, consisting of four Unit Telescopes with main mirrors 8.2-m in diameter and four movable 1.8-m diameter Auxiliary Telescopes. The telescopes can work together, in groups of two or three, to form a giant interferometer, allowing astronomers to see details up to 25 times finer than with the individual telescopes. Credit: European Southern Observatory — The Very Large Telescope (VLT) at ESO’s Cerro Paranal observing site. Credit: European Southern Observatory

“Its current location raises questions about its formation process,” stated team member Anne-Marie Lagrange, who is with the Grenoble Institute of Planetology and Astrophysics in France.

“It either grew by assembling the rocks that form the solid core and then slowly accumulated gas from the environment to form the heavy atmosphere, or started forming from a gaseous clump that arose from gravitational instabilities in the disc.

“Interactions between the planet and the disc itself,” she added, “or with other planets may have also moved the planet from where it was born.”

Astronomers estimate the planet candidate has a surface temperature of 1,292 degrees Fahrenheit (700 degrees Celsius), which could allow water vapor or methane to stick around in the atmosphere. It will take more VLT observations to figure this out, though.

The results from this study will be published in Astrophysical Journal Letters. The paper is also available on prepublishing site Arxiv.

Source: European Southern Observatory

May 25, 2013December 23, 2015 by Elizabeth Howell

Rocky Alien Planets: What The Heck Is On Their Surfaces?

NASA's Kepler mission confirmed the discovery of its first rocky planet, named Kepler-10b. Measuring 1.4 times the size of Earth, it is the smallest planet ever discovered outside our solar system.

We don’t have the budget yet to send Star Trek‘s U.S.S. Enterprise to probe the surface of strange new worlds, but luckily for humanity, astronomers are figuring out techniques to do that without even needing to leave Earth.

One of Earth’s prolific planet-hunters, the Kepler Space Telescope, has found a lot of planet candidates with rocky surfaces. That’s exciting for astronomers, as rocky planets tend to be smaller than their gas giant counterparts. Also, learning more about rocky planets could give us more clues as to Earth’s history, and that of other planets in our solar system.

But how the heck, from so far away, can we begin to understand the surface? One idea: Check the heat signature, or in more scientific words, look at exoplanets in the infrared part of the light spectrum.

The visible colors, infrared, radio, X-rays and gamma rays are all forms of light and comprise the electromagnetic spectrum. Here you can compare their wavelengths with familiar objects and see how their frequencies (bottom numbers) increase with decreasing wavelength. Credit: ESA

NASA’s Astrobiology Magazine recently published an article about this method, which we encourage you to check out. In summary, the team behind a new research paper (submitted to the Astrophysical Journal) proposes to check out “airless” exoplanets that have surface temperatures below 3,140 degrees Fahrenheit (1,726 Celsius or 2,000 Kelvin.)

Because different kinds of rocks emit “signature” spectrums in different wavelengths, it’s possible we could pick up the signs of silicate rocks or other types of material. There’s a caveat, though.

“With current technology, however, the team cautions that determining surface composition of exoplanets is a very different process than studying their solar system counterparts,” the magazine wrote. “Due to the limits of technology, the team proposes to concentrate on the most prominent mineral signatures detected from exoplanets.”

Check out more details in the scientific journal article here, or the entire Astrobiology Magazine article at this link.

April 26, 2013December 23, 2015 by Elizabeth Howell

How Do You Measure A Planet Near A Tiny Star?

Artist's conception of the Kepler Space Telescope. Credit: NASA/JPL-Caltech

When you sit back and think about how far away exoplanets are — and how faint — it’s a scientific feat that we can find these distant worlds outside our Solar System at all. It’s even harder to learn about the world if the exoplanet is orbiting a dim star — say, about two-thirds the size of the Sun — that is faint through even the largest telescope.

In response to this problem, there’s one science team that thinks it’s found a way to solve it. Their research bumped a planet from the habitable zone to the not-so-friendly zone of a star. Here’s how it happened:

The usual way to measure a distant star is this: look at the light. A Sun-sized star, for example, would have its light waves measured at different wavelengths. Scientists then match what they see to spectra (light bands) that are created artificially.

This method doesn’t work so well for smaller stars, though. “The challenge is that small stars are incredibly difficult to characterize,” stated Sarah Ballard, a post-doctoral researcher at the University of Washington, in a press release. Worse, these small guys make up about two-thirds of the stars in the universe.

Red Dwarf star and planet. Artists impression (NASA)

Ballard led a multi-university team describing a “characterization by proxy” method accepted for publication in The Astrophysical Journal and now available online.

The science team based their work on previous research performed by astronomer Tabetha Boyajian, who is currently at Yale University.

Boyajian combined the resources of several telescopes that measured wavelengths of light, wavelengths that are slightly longer than visible light. This technique allowed the interferometer (the combined telescopes) to figure out the size of stars that are close by.

With that data on hand, Ballard and her colleagues looked out into the universe. Their target was Kepler-61b (Kepler Object 1361.01), a “candidate” planet about double the size of Earth spotted by the planet-hunting Kepler space telescope. The candidate, if proven, is orbiting a low-mass star 900 light-years away that is hard to measure in a telescope.

Kepler space telescope's field of view. Credit: NASA — Kepler space telescope’s field of view. Credit: NASA

Next, the scientists picked four nearby stars that have similar light patterns, reasoning that they would be spectroscopially close enough to Kepler-61b’s parent star to make accurate measurements. The four stars are located in Ursa Major and Cygnus, ranging between 12 to 25 light years away from Earth.

When the scientists compared the measurements to Kepler 61’s star, a surprise emerged.

“Kepler-61 turned out to be bigger and hotter than expected,” the University of Washington stated. “This in turn recalibrated planet Kepler-61b’s relative size upward as well — meaning it, too, would be hotter than previously thought and no longer a resident of the star’s habitable zone.”

The newly refined planetary radius for Kepler-61b is 2.15 times the radius of Earth (plus or minus 0.13 radii). Astronomers estimate it orbits its star about once every 59.9 days and has a temperature of 273 Kelvin (plus or minus 13 Kelvin.)

Artist's impression of the habitable zone around variously sized stars. Credit: NASA — Artist’s impression of the habitable zone around variously sized stars. Credit: NASA

Just to wrap up, here’s a note about how likely it is that Kepler-61b is actually a planet — and not a planetary candidate.

The candidate was first described in this 2011 scientific paper. Kepler-61b is just one in a long list of 1,235 planetary candidates catalogued in that paper, all discovered in just four months — between May 2 and Sept. 16, 2009.

While the NASA Exoplanet Archive still lists Kepler-61b as a candidate planet — one that must be confirmed by independent observations — this 2011 paper says that most Kepler candidates have a strong possibility of being actual planets because the Kepler software is technologically apt.

In other words, Ballard and her co-authors write in the research, Kepler-61b is very likely to be a planet itself — with only 4.8 percent possibility of being a “false positive”, to be exact.

Source: University of Washington

April 9, 2013December 23, 2015 by Elizabeth Howell

How To Crowdsource Astronomy Without People Messing It Up

A family portrait of the PH1 planetary system that was discovered in part due to crowdsourcing. Image Credit: Haven Giguere/Yale.

Maybe it’s because Jurassic Park is in theaters again, but we at Universe Today sometimes worry about how one person can mess up an otherwise technologically amazing system. It took just one nefarious employee to shut down the dinosaur park’s security fences in the movie and cause havoc. How do we ensure science can fight against that, especially when everyday citizens are getting more and more involved in the scientific process?

But perhaps, after talking to Chris Lintott, that view is too suspicious. Lintott is in charge of a collaborative astronomy and science project called the Zooniverse that uses public contributions to fuel some of the science he performs. Basically, anyone with an Internet connection and a desire to contribute can hunt for planets or examine astronomical objects, among many other projects.

Lintott, an astrophysicist at the University of Oxford, says the science requires public contributions. Moreover, he hasn’t had a problem yet despite 800,000 individual contributors to the Zooniverse. He told Universe Today about how that’s possible in an e-mail interview.

1) Zooniverse has already produced tangible scientific results in space through collaborating with ordinary folks. Can you talk about some of the papers/findings that have been produced in your various projects?

There’s a long, long list. I’m particularly excited at the minute about our work on bulgeless galaxies; most spiral galaxies have a bulge full of old stars at their centre, but we’ve found plenty that don’t. That’s exciting because we think that means that they’re guaranteed not to have had a big merger in the last 10 billion years or so, and that means we can use them to figure out just what effect mergers have on galaxies. You’ll be hearing more about them in the next year or so as we have plenty of observing time lined up.

I’m also a big fan of Planet Hunters 1b, our first confirmed planet discovery – it’s a planet in a four-star system, and thus provides a nice challenge to our understanding of how planets form. We’ve found lots of planet candidates (systems where we’re more than 90% sure there’s a planet there) but it’s nice to get one confirmed and especially nice for it to be such an interesting world.

One of Zooniverse's projects examines the nature of spiral galaxies, particularly those without central bulges at the center. Credit: NASA, ESA, the Hubble Heritage Team (STScI/AURA)-ESA/Hubble Collaboration and A. Evans (University of Virginia, Charlottesville/NRAO/Stony Brook University) — One of Zooniverse’s projects examines the nature of spiral galaxies, particularly those without central bulges at the center. Credit: NASA, ESA, the Hubble Heritage Team (STScI/AURA)-ESA/Hubble Collaboration and A. Evans (University of Virginia, Charlottesville/NRAO/Stony Brook University)

2) What benefits have you received from involving the public in space projects, in terms of results as well as raising awareness?

We couldn’t do our research any other way. Astronomers have got very good in the last few decades at collecting information about the universe, but we’re not always so good at learning how to use all of that information. The Zooniverse allows us to collaborate with hundreds of thousands of people so that we can scale our efforts to deal with that flood of data, and many of those volunteers go much further than just clicking on buttons we provide. So really our research is now driven in collaboration with thousands of people, spread all around the world – that’s an inspiring thought.

3) How many people do you manage in your space projects, approximately? How do you keep track of them all?

We have more than 800,000 registered volunteers – luckily, the computer keeps track of them (when they log in!).

4) How do you ensure their results meet the standards of scientific publication?

We carefully design projects so that we’re sure they will produce scientifically useful results before they’re launched; this usually means running a test with a small amount of data and comparing work done by volunteers with that of professionals. We usually find the volunteers are better than us! It helps that we have several people complete each task, so collectively we don’t make accidental mistakes.

5) How do you guard against somebody deliberately or accidentally altering the results?

The system insists that every classification is independent, and as we have several people look at each classification finding any deliberate attack would be easy – in any case, we’ve never seen any evidence of such a thing. Despite popular reports, most people are nice!

November 8, 2012December 23, 2015 by Jason Major

Astronomers Find Tantalizing Hints of a Potentially Habitable Exoplanet

Dwarf star HD 40307 is now thought to host at least 6 exoplanet candidates… one of them well within its habitable zone. (G. Anglada/Celestia)

Located 43 light-years away in the southern constellation Pictor, the orange-colored dwarf star HD 40307 has previously been found to hold three “super-Earth” exoplanets in close orbit. Now, a team of researchers poring over data from ESO’s HARPS planet-hunting instrument are suggesting that there are likely at least six super-Earth exoplanets orbiting HD 40307 — with one of them appearing to be tucked neatly into the star’s water-friendly “Goldilocks” zone.

HARPS (High Accuracy Radial velocity Planet Searcher) on ESO’s La Silla 3.6m telescope is a dedicated exoplanet hunter, able to detect the oh-so-slight wobble of a star caused by the gravitational tug of orbiting planets. Led by Mikko Tuomi of the UK’s University of Hertfordshire Centre for Astrophysics Research, a team of researchers reviewed publicly-available data from HARPS and has identified what seems to be three new exoplanets in the HD 40307 systems. The candidates, designated with the letters e, f, and g, all appear to be “super Earth” worlds… but the last one, HD 40307 g, is what’s getting people excited, as the team has calculated it to be orbiting well within the region where liquid water could exist on its surface — this particular star’s habitable zone.

In addition, HD 40307 g is located far enough away from its star to likely not be tidally locked, according to the team’s paper. This means it wouldn’t have one side subject to constant heat and radiation while its other “far side” remains cold and dark, thus avoiding the intense variations in global climate, weather and winds that would come as a result.

“The star HD 40307, is a perfectly quiet old dwarf star, so there is no reason why such a planet could not sustain an Earth-like climate.”
– Guillem Anglada-Escudé, co-author.

“If the signal corresponding to HD 40307 g is a genuine Doppler signal of planetary origin, this candidate planet might be capable of supporting liquid water on its surface according to the current definition of the liquid water habitable zone around a star and is not likely to suffer from tidal locking.” (Tuomi et al.)

If HD 40307 g is indeed confirmed, it may very well get onto the official short list of potentially habitable worlds outside our Solar System — although those others are quite a bit closer to the mass of our own planet.

UPDATE: HD 40307 g has been added to the Planetary Habitability Laboratory’s Habitable Exoplanets Catalog, maintained by the PHL at the University of Puerto Rico at Arecibo. It’s now in 4th place of top exoplanets of interest based on similarity to Earth. According to Professor Abel Mendez Torres of the PHL, “Average temperatures might be near 9°C (48°F) assuming a similar scaled-up terrestrial atmosphere. It might also experience strong seasonal surface temperature shifts between -17° to 52°C (1.4° to 126°F) due to its orbital eccentricity. Nevertheless, these extremes are tolerable by most complex life, as we know it.” (Read more here.)

While the other planetary candidates in the HD 40307 system are positioned much more closely to the star, with b, c, d, and e within or at the equivalent orbital distance of Mercury, g appears to be in the star’s liquid-water habitable zone, orbiting at 0.6 AU in an approximately 200-day-long orbit. At this distance the estimated 7-Earth-mass exoplanet receives around 62-67% of the radiation that Earth gets from the Sun.

Representation of the liquid water habitable zone around HD 40307 compared to our Solar System (Tuomi et al., from the team’s paper.)

Although news like this is exciting, as we’re always eagerly anticipating the announcement of a true, terrestrial Earthlike world that could be host to life as we know it, it’s important to remember that HD 40307 g is still a candidate — more observations are needed to not only confirm its existence but also to find out exactly what kind of planet it may be.

“A more detailed characterization of this candidate is very unlikely using ground based studies because it is very unlikely [sic] to transit the star, and a direct imaging mission seems the most promising way of learning more about its possible atmosphere and life-hosting capabilities,” the team reports.

Read: How Well Can Astronomers Study Exoplanet Atmospheres?

Still, just finding potential Earth-sized worlds in a system like HD 40307’s is a big deal for planetary scientists. This system is not like ours, yet somewhat similar planets have still formed… that in itself is a clue to what else may be out there.

“The planetary system around HD 40307 has an architecture radically different from that of the solar system… which indicates that a wide variety of formation histories might allow the emergence of roughly Earth-mass objects in the habitable zones of stars.”

The team’s paper will be published in the journal Astronomy & Astrophysics. http://arxiv.org/pdf/1211.1617v1.pdf

Another researcher on the team, Guillem Anglada-Escudé of Germany’s Universität Göttingen, assembled this tour of the HD 40307 system (not including g) via Celestia.

Inset image: current potentially habitable exoplanets. Credit: PHL @ UPR Arecibo.

October 11, 2012April 26, 2016 by Jason Major

Nearby Exoplanet Could Be Covered With Diamond

Illustration of 55 Cancri e, a super-Earth that’s thought to have a thick layer of diamond (Yale News/Haven Giguere)

If diamonds are forever then this planet should be around for a very, very long time; it appears to be literally made of the stuff.

55 Cancri e — an exoplanet discovered in 2004 — is more than twice Earth’s diameter and over eight times more massive, making it a so-called “super Earth.” Earlier this year it made headlines by being the first Earth-sized exoplanet whose light was directly observed via the infrared capabilities of NASA’s Spitzer Space Telescope.

Using information about 55 Cancri e’s size, mass and orbital velocity, as well as the composition of its parent star 55 Cancri (located 40 light years away in the constellation Cancer) a research team led by scientists from Yale University created computer models to determine what the planet is most likely made of.

They determined that 55 Cancri e is composed primarily of carbon (as graphite and diamond), iron, silicon carbide, and possibly some silicates. The researchers estimate that at least a third of the planet’s mass — the equivalent of about three Earth masses — could be diamond.

“This is our first glimpse of a rocky world with a fundamentally different chemistry from Earth. The surface of this planet is likely covered in graphite and diamond rather than water and granite.”

– Nikku Madhusudhan, Yale postdoctoral researcher and lead author

So what would one expect to find on a world made of diamond?

“On this planet there would basically be a thin layer below the surface which will have both graphite and diamond,” Madhusudhan told Universe Today in an email. “But, below that there will be a thick layer (a third of the radius) with mostly diamond. For a large part the diamond will be like the diamond on Earth, except really, really pure.

“But at greater depths the diamond could also be in liquid form,” Madhusudhan added.

Scientists had previously thought that 55 Cancri e might have a lot of water — superheated water, due to the planet’s incredibly high 4,000-degree (F) temperatures — based on the assumption that its composition is similar to Earth’s. But this new research indicates that it doesn’t have much water at all.

“By contrast, Earth’s interior is rich in oxygen, but extremely poor in carbon — less than a part in thousand by mass,” said Kanani Lee, Yale geophysicist and co-author of the paper.

This study shows that we can’t assume that planets in other systems are made of the same stuff that ours is, even if they are of similar size (and also that diamonds aren’t necessarily a valuable commodity on all worlds!)

The team’s paper “A Possible Carbon-rich Interior in Super-Earth 55 Cancri e” was accepted for publication in the journal Astrophysical Journal Letters. Read more on Yale News here.

Top image by Haven Giguere. Inset image shows visible location of 55 Cancri, by Nikku Madhusudhan using Sky Map Online.

May 3, 2012December 23, 2015 by Jason Major

Will This Be The Fate Of The Earth?

Artist's impression of PG0843+516, a white dwarf star surrounded by Earthlike planetary remains. (© Mark A. Garlick / space-art.co.uk / University of Warwick)

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Astronomers have found four nearby white dwarf stars surrounded by disks of material that could be the remains of rocky planets much like Earth — and one star in particular appears to be in the act of swallowing up what’s left of an Earthlike planet’s core.

The research, announced today by the Royal Astronomical Society, gives a chilling look at the eventual fate that may await our own planet.

Astronomers from the University of Warwick used Hubble to identify the composition of four white dwarfs’ atmospheres, found during a survey of over 80 such stars located within 100 light-years of the Sun. What they found was a majority of the material was composed of elements found in our own Solar System: oxygen, magnesium, silicon and iron. Together these elements make up 93% of our planet.

In addition, a curiously low ratio of carbon was identified, indicating that rocky planets were at one time in orbit around the stars.

Since white dwarfs are the leftover cores of stellar-mass stars that have burnt through all their fuel, the material in their atmosphere is likely the leftover bits of planets. Once held in safe, stable orbits, when their stars neared the ends of their lives they expanded, possibly engulfing the innermost planets and disrupting the orbits of others, triggering a runaway collision effect that eventually shattered them all, forming an orbiting cloud of debris.

This could very well be what happens to our Solar System in four or five billion years.

“What we are seeing today in these white dwarfs several hundred light years away could well be a snapshot of the very distant future of the Earth,” said Professor Boris Gänsicke of the Department of Physics at the University of Warwick, who led the study. “During the transformation of the Sun into a white dwarf, it will lose a large amount of mass, and all the planets will move further out. This may destabilise the orbits and lead to collisions between planetary bodies as happened in the unstable early days of our solar systems.”

colliding_planets — Three easy steps to planetary destruction. (© Mark A. Garlick / space-art.co.uk / University of Warwick)

One of the white dwarfs studied, labeled PG0843+516, may even be actively eating the remains of an once-Earthlike world’s core.

The researchers identified an abundance of heavier elements like iron, nickel and sulphur in the atmosphere surrounding PG0843+516. These elements are found in the cores of terrestrial planets, having sunk into their interiors during the early stages of planetary formation. Finding them out in the open attests to the destruction of a rocky world like ours.

Of course, being heavier elements, they will be the first to be accreted by their star.

“It is entirely feasible that in PG0843+516 we see the accretion of such fragments made from the core material of what was once a terrestrial exoplanet,” Prof. Gänsicke said.

It’s an eerie look into a distant future, when Earth and the inner planets could become just some elements in a cloud.

Read the full story on the RAS site here.

November 28, 2011December 24, 2015 by Jason Major

An Exoplanet’s Auroral Engine

Aurora like the ones seen on October 24, 2011 as far south as Texas and Georgia would be commonplace on CoRoT-2b. (Image from the all-sky AuroraMax camera in Yellowknife, Ontario. http://twitpic.com/75owna )

Located 880 light-years away, a massive gas giant called CoRoT-2b orbits its star at a mere 2 million miles – less than a tenth the distance of Mercury’s orbit from the Sun. At this cozy proximity the star, CoRoT-2a, continually assaults the hot, gassy exoplanet with high-powered stellar winds and magnetic storms, stripping it of millions of kilograms of mass every day… and undoubtedly creating global auroras that rival even the most energetic seen on Earth.

But CoRoT-2b isn’t merely a tragic player in this stormy stellar performance; the planet itself may also be part of the cause.

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Almost 3 1/2 times the mass of Jupiter, CoRoT-2b (so named because it was discovered by the French Space Agency’s Convection, Rotation and planetary Transits space telescope, or CoRoT) orbits its star very rapidly, completing an orbit every 1.7 days. This in turn actually speeds up the rotation of the star itself thus generating even more magnetic activity, via a dynamo effect.

Caught up in this deadly dance, CoRoT-2b is losing mass at an estimated rate of 150 million billion kilograms of material every year! The planet would likely have a long comet-like tail of this stripped material trailing behind it.

Although this sounds like a lot, CoRoT-2b has enough mass to keep “spinning up” its star for thousands of billions of years.