Posted on by Nancy Atkinson

Another Exoplanet Hunting Mission Ends: CoRoT Spacecraft Can’t be Recovered

The COROT spacecraft. Credits: CNES/D. Ducros

More bad news on the exoplanet-hunting front: While the final fate of the Kepler spacecraft remains unknown, the CoRoT (Convection, Rotation and Planetary Transits) satellite has now been officially shut down. CoRoT suffered a computer failure on November, 2, 2012 and although the spacecraft is capable of receiving navigational commands, the French Space Agency CNES reports it can no longer retrieve data from its 30-centimeter telescope. After a valiant effort to try and restore the computer, CNES announced this week that the spacecraft has been retired. CoRoT’s journey will come to a fiery end as it will be deorbited and it will burn up on re-entry in Earth’s atmosphere.

While it’s always hard to see the end of successful mission, we can’t be too sad about CoRoT, however. The mission lasted twice as long as expected and it gathered a remarkable haul of exoplanets. CoRoT looked for planetary transits — a dimming in brightness of the host star as a planet crossed in front. CoRoT was the first mission to find a planet using the transit method.

In all, CoRoT has spotted 32 confirmed planets and at least 100 more are awaiting confirmation. The mission also allowed astronomers to study the stellar physics and the interior of stars.

This is not the first computer failure for the mission. CoRoT launched in December of 2006, and in 2009 the main computer failed and has since been running on the backup computer. When the second computer failed in November, engineering teams have tried to reboot both computers, with no success.

But space radiation is tough on spacecraft, and after enduring 6 years of intense bombardment by high-energy particles in space, both computers have been deemed unrecoverable.

CNES said a series of operations will be performed to lower CoRoT’s orbit and conduct some technology experiments before passivating and deorbiting the satellite. Its journey will end as it burns up on re-entry in Earth’s atmosphere.

Family portrait of the first 15 CoRoT planets. Credit: Patrice Amoyel (CNES)
Family portrait of the first 15 CoRoT planets. Credit: Patrice Amoyel (CNES)

CoRoT discovered a diverse array of planets, mostly gas giants. Some of the planets discovered, like CoRoT-7b, orbit their star in less than 24 hours and have a blistering hot surface, while others like CoRoT-9b have an orbital period of 95 days and is one of very few known “warm” transiting exoplanets.

CoRoT was also the first to obtain measurements of the radius of brown dwarves, intermediate objects between a planet and a star, and literally opened up a whole new field of study of temporal analysis of the micro-variability of stars by measuring the frequencies and amplitudes of stellar vibrations with unprecedented precision.

CNES did not provide a timetable for CoRoT’s demise, but we’ll keep you posted.

Source: CNES

Posted on by Nancy Atkinson

Three Potentially Habitable Planets Found Orbiting Gliese 667C

Nearby star Gliese 667C might have three potentially habitable planets. Credit: Planetary Habitability Laboratory, University of Puerto Rico Arecibo.

A closer look at the previously-studied nearby star Gliese 667C has revealed a treasure trove of planets – at least six – with three super-Earths in the habitable zone around the star. Gliese 667C is part of a triple star system (Gliese 667) and is just over one third of the mass of our Sun. Now that we know there are multiple planets in the so-called Goldilocks zone – a region where liquid water could exist — Gliese 667C might be the best candidate for harboring habitable exo-worlds.

“We knew that the star had three planets from previous studies, so we wanted to see whether there were any more,” said Mikko Tuomi from the University of Hertfordshire in the UK, one of the astronomers who led the new study of Gliese 667C. “By adding some new observations and revisiting existing data we were able to confirm these three and confidently reveal several more. Finding three low-mass planets in the star’s habitable zone is very exciting!”

Artist’s conception of the seven planets possibly found orbiting Gliese 667C. Three of them (c, f and e) orbit within the habitable zone of the star. Image is courtesy of Rene Heller/ Carnegie Institution for Science.
Artist’s conception of the seven planets possibly found orbiting Gliese 667C. Three of them (c, f and e) orbit within the habitable zone of the star. Image is courtesy of Rene Heller/ Carnegie Institution for Science.

Tuomi, along with Guillem Anglada-Escudé of the University of Göttingen, Germany looked at existing radial velocity data from the HARPS spectrograph at ESO’s 3.6-metre telescope in Chile. The team said they are extremely confident on the data on the first five planets, while the sixth is tentative, and a potential seventh planet even more tentative.

The team writes in their paper:

Up to seven periodic signals are detected in the Doppler measurements of GJ 667C data, being the last (seventh) signal very close to our detection threshold.

The significance of the signals is not affected by correlations with activity indices and we could not identify any strong wavelength dependence with any of them.

The first six signals are strongly present in subsamples of the data. Only the seventh signal is unconfirmed using half of the data only. Our analysis indicates that any of the six stronger signals would had been robustly spotted with half the available data if each had been orbiting alone around the host star.

If all seven planets are confirmed, the system would consist of three habitable-zone super-Earths, two hot planets further in, and two cooler planets further out.

This diagram shows the system of planets around the star Gliese 667C. A record-breaking three planets in this system are super-Earths lying in the zone around the star where liquid water could exist, making them possible candidates for the presence of life. This is the first system found with a fully packed habitable zone. The relative approximate sizes of the planets and the parent star are shown to scale, but not their relative separations. Credit: ESO
This diagram shows the system of planets around the star Gliese 667C. A record-breaking three planets in this system are super-Earths lying in the zone around the star where liquid water could exist, making them possible candidates for the presence of life. This is the first system found with a fully packed habitable zone. The relative approximate sizes of the planets and the parent star are shown to scale, but not their relative separations. Credit: ESO

But the team said the three in the habitable zone are confirmed to be super-Earths. These are planets more massive than Earth, but less massive than planets like Uranus or Neptune. This is the first time that three such planets have been spotted orbiting in this zone in the same system.

“The number of potentially habitable planets in our galaxy is much greater if we can expect to find several of them around each low-mass star,” said co-author Rory Barnes from the University of Washington, “instead of looking at ten stars to look for a single potentially habitable planet, we now know we can look at just one star and find several of them.”

Gliese 667 (a.k.a GJ 667) is 22 light-years away from Earth in the constellation of Scorpius.
The planets in the habitable zone and those closer to the star are expected to always have the same side facing the star, so that their day and year will be the same lengths, with one side in perpetual sunshine and the other always night.

The researchers say that the ‘f’ planet is “a prime candidate for habitability.”

“It likely absorbs less energy than the Earth, and hence habitability requires more greenhouse gases, like CO2 or CH4,” the team wrote in their paper. “Therefore a habitable version of this planet has to have a thicker atmosphere than the Earth, and we can assume a relatively uniform surface temperature.”

The other stars in the triple system would provide a unique sunset: the two other suns would look like a pair of very bright stars visible in the daytime and at night they would provide as much illumination as the full Moon.

Are there more planets to be found in this abundant system? Perhaps, but not in the habitable zone. The team said the new planets completely fill up the habitable zone of Gliese 667C, as there are no more stable orbits in which a planet could exist at the right distance to it.

An artist’s impression of the orbits of the planets in the Gliese 667C system:

Read the team’s paper.

Sources: ESO, Carnegie , Planetary Habitability Laboratory

Posted on by Jason Major

Flying Space Toasters: Electrified Exoplanets Really Feel the Heat

Artist's concept of Jupiter-sized exoplanet that orbits relatively close to its star (aka. a "hot Jupiter"). Credit: NASA/JPL-Caltech)
Artist's concept of Jupiter-sized exoplanet that orbits relatively close to its star (aka. a "hot Jupiter"). Credit: NASA/JPL-Caltech)

Overheated and overinflated, hot Jupiters are some of the strangest extrasolar planets to be discovered by the Kepler mission… and they may be even more exotic than anyone ever thought. A new model proposed by Florida Gulf Coast University astronomer Dr. Derek Buzasi suggests that these worlds are intensely affected by electric currents that link them to their host stars. In Dr. Buzasi’s model, electric currents arising from interactions between the planet’s magnetic field and their star’s stellar wind flow through the interior of the planet, puffing it up and heating it like an electric toaster.

In effect, hot Jupiters are behaving like giant resistors within exoplanetary systems.

Many of the planets found by the Kepler mission are of a type known as “hot Jupiters.” While about the same size as Jupiter in our own solar system, these exoplanets are located much closer to their host stars than Mercury is to the Sun — meaning that their atmospheres are heated to several thousands of degrees.

One problem scientists have had in understanding hot Jupiters is that many are inflated to sizes larger than expected for planets so close to their stars. Explanations for the “puffiness” of these exoplanets have generally involved some kind of extra heating process — but no model successfully explains the observation that more magnetically active stars tend to have puffier hot Jupiters orbiting around them.

“This kind of electric heating doesn’t happen very effectively on planets in our solar system because their outer atmospheres are cold and don’t conduct electricity very well,” says Dr. Buzasi. “But heat up the atmosphere by moving the planet closer to its star and now very large currents can flow, which delivers extra heat to the deep interior of the planet — just where we need it.”

More magnetically active stars have more energetic winds, and would provide larger currents — and thus more heat — to their planets.

The currents start in the magnetosphere, the area where the stellar wind meets the planetary magnetic field, and enter the planet near its north and south poles. This so-called “global electric circuit” (GEC) exists on Earth as well, but the currents involved are only a few thousand amps at 100,000 volts or less.

On the hot Jupiters, though, currents can amount to billions of amps at voltages of millions of volts — a “significant current,” according to Dr. Buzasi.

A Spitzer-generated exoplanet weather map showing temperatures on a hot Jupiter HAT-P-2b.
A Spitzer-generated exoplanet weather map showing temperatures on hot Jupiter HAT-P-2b.

“It is believed that these hot Jupiter planets formed farther out and migrated inwards later, but we don’t yet fully understand the details of the migration mechanism,” Dr. Buzasi says. “The better we can model how these planets are built, the better we can understand how solar systems form. That in turn, would help astronomers understand why our solar system is different from most, and how it got that way.”

Other electrical heating processes have previously been suggested by other researchers as well, once hints of magnetic fields in exoplanets were discovered in 2003 and models of atmospheric wind drag — generating frictional heating — as a result of moving through these fields were made in 2010.

(And before anyone attempts to suggest this process supports the alternative “electric universe” (EU) theory… um, no.)

“No, nothing EU-like at all in my model,” Dr. Buzasi told Universe Today in an email. “I just look at how the field aligned currents that we see in the terrestrial magnetosphere/ionosphere act in a hot Jupiter environment, and it turns out that a significant fraction of the resulting circuit closes inside the planet (in the outer 10% of the radius, mostly) where it deposits a meaningful amount of heat.”

This work will be presented at the 222nd meeting of the American Astronomical Society on June 4, 2013.

Posted on by Nancy Atkinson

Using the Theory of Relativity and BEER to Find Exoplanets

"Einstein's planet," formally known as Kepler-76b, is a "hot Jupiter" that orbits its star every 1.5 days. Its diameter is about 25 percent larger than Jupiter and it weighs twice as much. This artist's conception shows Kepler-76b orbiting its host star, which has been tidally distorted into a slight football shape (exaggerated here for effect). The planet was detected using the BEER algorithm, which looked for brightness changes in the star as the planet orbits due to relativistic BEaming, Ellipsoidal variations, and Reflected light from the planet. Credit: David A. Aguilar (CfA)

A new method of detecting alien worlds is full of awesome, as it combines Einstein’s Theory of Relativity along with BEER. No, not the weekend beverage of choice, but the relativistic BEaming, Ellipsoidal, and Reflection/emission modulations algorithm. This new way of finding exoplanets was developed by Professor Tsevi Mazeh and his student, Simchon Faigler, at Tel Aviv University, Israel, and it has been used for the first time to find a distant exoplanet, Kepler-76b, informally named Einstein’s planet.

“This is the first time that this aspect of Einstein’s theory of relativity has been used to discover a planet,” said Mazeh.

The two most-most used and prolific techniques for finding exoplanets are radial velocity (looking for wobbling stars) and transits (looking for dimming stars).

The new method looks for three small effects that occur simultaneously as a planet orbits the star. A “beaming” effect causes the star to brighten as it moves toward us, tugged by the planet, and dim as it moves away. The brightening results from photons “piling up” in energy, as well as light getting focused in the direction of the star’s motion due to relativistic effects.

The team also looked for signs that the star was stretched into a football shape by gravitational tides from the orbiting planet. The star would appear brighter when we observe the “football” from the side, due to more visible surface area, and fainter when viewed end-on. The third small effect is due to starlight reflected by the planet itself.

“This was only possible because of the exquisite data NASA is collecting with the Kepler spacecraft,” said Faigler.

This graphic shows Kepler-76b's orbit around a yellow-white, type F star located 2,000 light-years from Earth in the constellation Cygnus. Although Kepler-76b was identified using the BEER effect (see above), it was later found to exhibit a grazing transit, crossing the edge of the star's face as seen from Earth. Credit: Dood Evan.
This graphic shows Kepler-76b’s orbit around a yellow-white, type F star located 2,000 light-years from Earth in the constellation Cygnus. Although Kepler-76b was identified using the BEER effect (see above), it was later found to exhibit a grazing transit, crossing the edge of the star’s face as seen from Earth.
Credit: Dood Evan.

Although scientists say this new method can’t find Earth-sized worlds using current technology, it offers astronomers a unique discovery opportunity. Unlike radial velocity searches, it doesn’t require high-precision spectra. Unlike transits, it doesn’t require a precise alignment of planet and star as seen from Earth.

“Each planet-hunting technique has its strengths and weaknesses. And each novel technique we add to the arsenal allows us to probe planets in new regimes,” said Avi Loeb from the Harvard-Smithsonian Center for Astrophysics, who first proposed the idea of this planet-hunting method back in 2003.

Kepler-76b is a “hot Jupiter” that orbits its star every 1.5 days. Its diameter is about 25 percent larger than Jupiter and it weighs twice as much. It orbits a type F star located about 2,000 light-years from Earth in the constellation Cygnus.

The planet is tidally locked to its star, always showing the same face to it, just as the Moon is tidally locked to Earth. As a result, Kepler-76b broils at a temperature of about 3,600 degrees Fahrenheit.

Interestingly, the team found strong evidence that the planet has extremely fast jet-stream winds that carry the heat around it. As a result, the hottest point on Kepler-76b isn’t the substellar point (“high noon”) but a location offset by about 10,000 miles. This effect has only been observed once before, on HD 189733b, and only in infrared light with the Spitzer Space Telescope. This is the first time optical observations have shown evidence of alien jet stream winds at work.

The planet has been confirmed using radial velocity observations gathered by the TRES spectrograph at Whipple Observatory in Arizona, and by Lev Tal-Or (Tel Aviv University) using the SOPHIE spectrograph at the Haute-Provence Observatory in France. A closer look at the Kepler data also showed that the planet transits its star, providing additional confirmation.

The paper announcing this discovery has been accepted for publication in The Astrophysical Journal and is available on arXiv.

Source: CfA

Posted on by Fraser Cain

Weekly Space Hangout – May. 3, 2013

Another busy episode of the Weekly Space Hangout, with more than a dozen space stories covered by a collection of space journalists. This week’s panel included Alan Boyle, Dr. Nicole Gugliucci, Amy Shira Teitel, David Dickinson, Dr. Matthew Francis, and Jason Major. Hosted by Fraser Cain. We discussed:

We record the Weekly Space Hangout every Friday at 12 pm Pacific / 3 pm Eastern. You can watch us live on Google+, Cosmoquest or listen after as part of the Astronomy Cast podcast feed (audio only).

Posted on by Nancy Atkinson

Watch Live Hangout: TESS and the Search for Exoplanets

Artist's rendition of TESS in space. (Credit: MIT Kavli Institute for Astrophysics Research).

Last month, NASA announced plans to launch the Transiting Exoplanet Survey Satellite (TESS) in 2017. This is a satellite that will perform an all-sky survey to discover transiting exoplanets in orbit around the brightest stars in the Sun’s neighborhood. “TESS will carry out the first space-borne all-sky transit survey, covering 400 times as much sky as any previous mission,” said George Ricker, the mission’s principal investigator. “It will identify thousands of new planets in the solar neighborhood, with a special focus on planets comparable in size to the Earth.”

Read more about the TESS mission here.

Today, Wednesday May 1, at 19:00 UTC (12:00 p.m. PDT, 3:00 pm EDT) you can take part in a live Google+ Hangout, and have your questions answered about TESS and the search for exoplanets with three leading members of NASA’s TESS mission:

George Ricker is principal investigator of the TESS mission and a senior research scientist at the MIT Kavli Institute for Astrophysics and Space Research (MKI) in Cambridge, Mass.

Sara Seager is a professor of planetary science and physics at MKI and a member of the TESS team. Seager’s research focuses on computer models of exoplanet atmospheres, interiors and biosignatures.

Joshua Winn is an associate professor of physics at MKI and deputy science director for the TESS mission. Winn is interested in the properties of planets around other stars, how planets form and evolve, and whether there are habitable planets beyond Earth.

Watch in the viewer above, or at the Kavli Foundation website.

Questions can be submitted ahead of and during this special event via Twitter using the hashtag #KavliAstro and by email to [email protected].

Posted on by Nancy Atkinson

Habitable Worlds? New Kepler Planetary Systems in Images

Relative sizes of Kepler habitable zone planets discovered as of 2013 April 18. Left to right: Kepler-22b, Kepler-69c, Kepler-62e, Kepler-62f, and Earth (except for Earth, these are artists' renditions). Credit: NASA/Ames/JPL-Caltech.

The Kepler mission has discovered two new planetary systems that include three super-Earth-size planets in the “habitable zone,” the range of distance from a star where the surface temperature of an orbiting planet might be suitable for liquid water.

The Kepler-62 system has five planets; 62b, 62c, 62d, 62e and 62f. The Kepler-69 system has two planets; 69b and 69c. Kepler-62e, 62f and 69c are the super-Earth-sized planets. (Read all the details in our full article here.)

The new planets brings the number of confirmed exoplanets to 861. According to the Planetary Habitability Laboratory, there are now nine potential habitable worlds outside of our solar system, with 18 more potentally habitable planetary candidates found by Kepler waiting to be confirmed. Additionally, astronomers predict there are 25 potentially habitable exomoons.

Here is some of the imagery (sorry, but they are artists concepts!), graphs and video used in today’s briefing about the new discoveries, as well as some some from the Planetary Habitability Laboratory:

Here’s a flythrough of the Kepler 62 system:

The diagram compares the planets of the inner solar system to Kepler-69, a two-planet system about 2,700 light-years from Earth. Image credit: NASA Ames/JPL-Caltech
The diagram compares the planets of the inner solar system to Kepler-69, a two-planet system about 2,700 light-years from Earth.
Image credit: NASA Ames/JPL-Caltech
Much like our solar system, Kepler-62 is home to two habitable zone worlds. The small shining object seen to the right of Kepler-62f is Kepler-62e. Orbiting on the inner edge of the habitable zone, Kepler-62e is roughly 60 percent larger than Earth. Image credit: NASA Ames/JPL-Caltech.
Much like our solar system, Kepler-62 is home to two habitable zone worlds. The small shining object seen to the right of Kepler-62f is Kepler-62e. Orbiting on the inner edge of the habitable zone, Kepler-62e is roughly 60 percent larger than Earth. Image credit: NASA Ames/JPL-Caltech.
The diagram compares the planets of the inner solar system to Kepler-62, a five-planet system about 1,200 light-years from Earth. Image credit: NASA Ames/JPL-Caltech
The diagram compares the planets of the inner solar system to Kepler-62, a five-planet system about 1,200 light-years from Earth. Image credit: NASA Ames/JPL-Caltech
Current known potentially habitable exoplanets. Credit: Planetary Habitability Laboratory/University of Puerto Rico, Arecibo.
Current known potentially habitable exoplanets. Credit: Planetary Habitability Laboratory/University of Puerto Rico, Arecibo.
Current potentially habitable exoplanets showing the new additions, Kepler-62e and Kepler-62f. Credit: Planetary Habitability Laboratory/University of Puerto Rico, Arecibo.
Current potentially habitable exoplanets showing the new additions, Kepler-62e and Kepler-62f. Credit: Planetary Habitability Laboratory/University of Puerto Rico, Arecibo.
Comparison of the orbit and size of the exoplanets of Kepler-62 with the terrestrial planets of our Solar Systems. The darker green shaded area corresponds to the 'conservative habitable zone' while its lighter borders to its 'optimistic habitable zone' extension. Planet sizes and orbits are not to scale between them. Credit: Planetary Habitability Laboratory/University of Puerto Rico, Arecibo.
Comparison of the orbit and size of the exoplanets of Kepler-62 with the terrestrial planets of our Solar Systems. The darker green shaded area corresponds to the ‘conservative habitable zone’ while its lighter borders to its ‘optimistic habitable zone’ extension. Planet sizes and orbits are not to scale between them. Credit: Planetary Habitability Laboratory/University of Puerto Rico, Arecibo.

Posted on by Nancy Atkinson

Kepler Team Finds System with Two Potentially Habitable Planets

The newly discovered planets named Kepler-62e and -f are super-Earths in the habitable zone of a distant sun-like star. The largest planet in the image, Kepler-62f, is farthest from its star and covered by ice. Kepler-62e, in the foreground, is nearer to its star and covered by dense clouds. Closer in orbits a Neptune-size ice giant with another small planet transiting its star. Both habitable-zone planets may be capable of supporting life. Credit: David A. Aguilar (CfA)

This might be the most exciting exoplanet news yet. An international team of scientists analyzing data from NASA’s Kepler mission has found a planetary system with two small, potentially rocky planets that lie within the habitable zone of their star. The star, Kepler-62, is a bit smaller and cooler than our Sun, and is home to a five-planet system. Two of the worlds, Kepler-62e and Kepler-62f are the smallest exoplanets yet found in a habitable zone, and they might both be covered in water or ice, depending on what kind of atmosphere they might have.

“Imagine looking through a telescope to see another world with life just a few million miles from your own. Or, having the capability to travel between them on a regular basis. I can’t think of a more powerful motivation to become a space-faring society,” said Harvard astronomer Dimitar Sasselov, who is co-author of a new paper describing the discovery.

Masses and sizes for selected planets. The curves show the mass-radius-relation (average density) for different types of planets: The blue line indicates the loci of planets made mostly (75%) of water, the black line that of planets like our Earth that consist almost exclusively of rock (represented here by the mineral Enstatite, MgSiO3, a member of the pyroxite silicate mineral series that makes up most of the Earth's mantle), and so on. The measured radii of Kepler-62e and Kepler-62f plus an estimate of their mass places them in a region (blue areas) where it is highly probable for them to be earth-like planets, that is: planets with a solid (if possibly covered in water) surface. Kepler-11f, on the other hand, is a Mini-Neptune, showing clearly that a comparatively low mass does not necessarily make for a solid planet. Image: L. Kaltenegger (MPIA)
Masses and sizes for selected planets. The curves show the mass-radius-relation (average density) for different types of planets: The blue line indicates the loci of planets made mostly (75%) of water, the black line that of planets like our Earth that consist almost exclusively of rock (represented here by the mineral Enstatite, MgSiO3, a member of the pyroxite silicate mineral series that makes up most of the Earth’s mantle), and so on. The measured radii of Kepler-62e and Kepler-62f plus an estimate of their mass places them in a region (blue areas) where it is highly probable for them to be earth-like planets, that is: planets with a solid (if possibly covered in water) surface. Kepler-11f, on the other hand, is a Mini-Neptune, showing clearly that a comparatively low mass does not necessarily make for a solid planet. Image: L. Kaltenegger (MPIA)

Kepler-62 in the constellation Lyra, and is about 1,200 light-years from Earth.

62e is 1.61 times Earth’s size, circles the star in 122.4 (Earth) days. 62f is 1.4 times the size of Earth, and orbits its star in 267.3 days. Previously, the smallest planet with known radius inside a habitable zone was Kepler-22b, with a radius of 2.4 times that of the Earth.

A third planet in another star system was also announced at a press briefing today. Kepler-69c is 70 percent larger than the size of Earth, and orbits in the habitable zone of a star similar to our Sun. Researchers are uncertain about the composition of Kepler-69c, but astronomer Thomas Barclay from the BAER Institute said its closer orbit of 242 days around a Sun-like star means it is likely more like a super-Venus rather than a super-Earth.

The habitable zone (in which liquid water on a planet's surface can exist) for different types of stars. The inner planets of our Solar System are shown on top, with Earth and Mars in the habitable zone. Kepler-62 is a notably cooler star, and Kepler-62e and -62f are in its habitable zone. For Kepler-69c, another planet announced today by NASA, the error bars for the star's radiation are such that it could possibly in the habitable zone as well. Kepler-22b, the smallest planet found in a habitable zone before the recent discoveries, is very likely a Mini-Neptune, and not a solid planet. In what is denoted the empirical habitable zone, liquid water can exist on the surface of a planet if that planet has sufficient cloud cover. In the narrow habitable zone, liquid water can exist on the surface even without the presence of a cloud cover. Image: L. Kaltenegger (MPIA)
The habitable zone (in which liquid water on a planet’s surface can exist) for different types of stars. The inner planets of our Solar System are shown on top, with Earth and Mars in the habitable zone. Kepler-62 is a notably cooler star, and Kepler-62e and -62f are in its habitable zone. For Kepler-69c, another planet announced today by NASA, the error bars for the star’s radiation are such that it could possibly in the habitable zone as well. Kepler-22b, the smallest planet found in a habitable zone before the recent discoveries, is very likely a Mini-Neptune, and not a solid planet. In what is denoted the empirical habitable zone, liquid water can exist on the surface of a planet if that planet has sufficient cloud cover. In the narrow habitable zone, liquid water can exist on the surface even without the presence of a cloud cover. Image: L. Kaltenegger (MPIA)

The team says that while the sizes of Kepler 62e and 62f are known, their mass and densities are not. However, every planet found in their size range so far has been rocky, like Earth.

Kepler-62 system. Five planets, two of which are in the Habitable Zone. Credit: NASA
Kepler-62 system. Five planets, two of which are in the Habitable Zone. Credit: NASA

“These planets are unlike anything in our solar system. They have endless oceans,” said lead author Lisa Kaltenegger of the Max Planck Institute for Astronomy and the Harvard Smithsonian Center for Astrophysics. “There may be life there, but could it be technology-based like ours? Life on these worlds would be under water with no easy access to metals, to electricity, or fire for metallurgy. Nonetheless, these worlds will still be beautiful blue planets circling an orange star — and maybe life’s inventiveness to get to a technology stage will surprise us.”

As the warmer of the two worlds, Kepler-62e would have a bit more clouds than Earth according to computer models. More distant Kepler-62f would need the greenhouse effect from plenty of carbon dioxide to warm it enough to host an ocean. Otherwise, it might become an ice-covered snowball.

“Kepler-62e probably has a very cloudy sky and is warm and humid all the way to the polar regions. Kepler-62f would be cooler, but still potentially life-friendly,” said Harvard astronomer and co-author Dimitar Sasselov. “The good news is — the two would exhibit distinctly different colors and make our search for signatures of life easier on such planets in the near future. “

The Kepler spacecraft is able to detect planets that transit or cross the face of their host star. Measuring a transit tells astronomers the size of the planet relative to its star.

“All of the other interesting planets in the habitable zone were until now discovered by what is known as the radial velocity method,” said Kaltenegger. “This method gives you a lower limit for the planet’s mass, but no information about its radius. This makes it difficult to assess whether or not a planet is rocky, like the Earth. A small radius (less than 2 Earth radii), on the other hand, is a strong indicator that a planet around is indeed rocky – unless we are talking about a planet around a very young star.”

“What makes Kepler-62e and Kepler-62f so exciting is a combination of two factors,” Kaltenegger added. “We know their radius, which indicates that these are indeed rocky planets, and they orbit their star in the habitable zone. That makes them our best candidates for habitable planets out there yet.

Kaltenegger provides more details on these exoplanets in this video:

Sources: Max Planck Institute for Astronomy, CfA

Posted on by Nancy Atkinson

The Exoplanet Naming Debate Heats Up

An artist's impression of an extra solar planet Photo credit: David A Hardy, astroart.org Copyright: STFC.

Following last Friday’s press release from the International Astronomical Union (IAU) concerning the naming of extrasolar planets, a heated debate has arisen over two separate but related issues. One is the “official” vs. “popular” names of astronomical objects (and the IAU’s jurisdiction over them) and the other is Uwingu’s intentions in their exoplanet naming contests.

We’re going to talk about the latter first, as this seems to be where much of the contention lies.

As has been reflected in our articles, Universe Today feels that Uwingu has always been upfront that the names chosen in their exoplanet naming contests were never meant to be “officially” recognized by the IAU, but instead are a way to engage the public and to create non-governmental funding for space research. As we said in our article on Nov. 7, 2012 about the first contest that creates a “baby book” of exoplanet names:

The names won’t be officially approved by the International Astronomical Union, but (Alan) Stern said they will be are similar to the names given to features on Mars by the mission science teams (such as the “Jake Matijevic” rock recently analyzed by the Curiosity rover) that everyone ends up using. This also solves the problem of how to come up with names, a task that the IAU has yet to discuss.

Please read these articles on Time and New Scientist which explicitly quote Uwingu CEO Alan Stern as saying the names generated by Uwingu’s contest will not be officially recognized by the IAU, but are a way to get the public involved and excited about exoplanets.

Anyone who implies that Uwingu is like the ‘name a star’ scams, or that they are out to make money to line their own pockets is completely misreading Uwingu’s website and completely missing the point. The profits go towards science research and education. So far Uwingu has given approximately $5,500 to several projects: Astronomers Without Borders, the Galileo Teacher Training Program, the Purdue Multiethnic Training Program, and the Allen Telescope Array for SETI.

Additionally, as the Uwingu Twitter feed confirmed, “No one at Uwingu has ever been paid, we have all worked for free from the start.”

The IAU’s statement on Friday infers that Uwingu is trying to sell “the rights to name exoplanets” and today Uwingu issued a statement that says the IAU’s press release “significantly mischaracterized Uwingu’s People’s Choice contest and Uwingu itself.”

As astronomer Carolyn Collins Petersen wrote on her Spacewriter’s Ramblings blog, nowhere on Uwingu’s website does it say that you’re buying the right to name a planet, as seems to be suggested by the IAU press release.

“If you donate a few dollars, you get to suggest a name,” she wrote. “You donate a few cents and you can vote for the coolest names. The coolest names win prizes. The money goes to research and education.”

And Stern has said the time has come where exoplanets should be named: “The IAU has had ten years to do something about this and they haven’t done anything,” he told Universe Today previously. “What we’re doing might be controversial, but that’s OK. It’s time to step up to the plate and do something.”

And many agree with his point that since the public is obviuosly intrigued and interested in exoplanets, they should be involved in the naming process, if only to suggest names. And as we’ve said before, since the IAU has said it will be difficult to come up with names since there are now hundreds of known explanets, Uwingu’s projects fits the bill of what is needed.

Also from Uwingu’s statement today:

Uwingu affirms the IAU’s right to create naming systems for astronomers. But we know that the IAU has no purview — informal or official — to control popular naming of bodies in the sky or features on them, just as geographers have no purview to control people’s naming of features along hiking trails. People clearly enjoy connecting to the sky and having an input to common-use naming. We will continue to stand up for the public’s rights in this regard, and look forward to raising more grant funds for space researchers and educators this way.

Over the weekend, the debate raged on the various social media outlets, and astronomer Jason Wright wrote a blog post that called out the IAU’s statement, saying it couldn’t be the official IAU policy, because “IAU policy is determined by democratic vote of its commissions and General Assembly. Neither has endorsed any nomenclature for planets, much less the assertions of the press release.”

Wright added that he contacted a member of Commission 53 (the IAU committee that will discuss the future of exoplanet naming) “and learned that they were not consulted for or even informed of this press release before it went out, and that the commission has not established a naming process since it met in Beijing in 2012.”

As far as the difference between “official” and “common” names, the IAU said in their press release that a “clear and systematic system for naming these objects is vital. Any naming system is a scientific issue that must also work across different languages and cultures in order to support collaborative worldwide research and avoid confusion.”

However, many people have pointed out that other sciences — like biology – have scientific names and common names that are both used and there doesn’t appear to be rampant confusion over this.

But stars can have several names as well, as astronomer Stuart Lowe wrote in his Astroblog, “Currently stars can have one proper name but also be in many different catalogues with different IDs.”

Uwingu pointed out in their statement that the star Polaris (its well-known common name!) is also known as the North Star, Alpha Ursae Minoris, HD 8890, HIP 11767, SAO 308, ADS 1477, FK5 907, and over a dozen more designations.

Uwingu also noted how non-scientific, informal names are prevalent in astronomy. Our own Milky Way galaxy is a great example, and “there are many instances where astronomers name things without going through the IAU’s internal process. There are many of features on Mars, ranging from mountains to individual rocks, with names applied by Mars-mission scientists and never adopted by, or even considered by, the IAU. And Apollo astronauts did not seek IAU permission before naming features at their landing sites or from orbit.”

Also, recent press releases reflect where astronomical objects were given names by astronomers without any IAU process such as Supernova Wilson, Galaxy cluster “El Gordo,” and the “Black Eye Galaxy.” “None drew attention from the IAU,” Uwingu said.

Planetary scientist and educator David Grinspoon (who is on Uwingu’s board of advisors) probably summed it up best in a comment he posted on Universe Today: “IAU maintains names for astronomers and that’s fine, but they do not own the sky. Planets are PLACES not just astronomical research objects, and if informal names for these places proliferate, outside of some self-appointed professional “authority”, and the public at large is more engaged in the exoplanet revolution, that is a very good thing indeed.”

Posted on by Nancy Atkinson

IAU Issues Response To Uwingu’s Exoplanet Naming Campaign

An exoplanet seen from its moon (artist's impression). Via the IAU.
An exoplanet seen from its moon (artist's impression). Via the IAU.

Given the popularity of the recent contest by Uwingu to suggest names for the closest known exoplanet to Earth (officially named Alpha Centauri Bb or ACBb for short), the International Astronomical Union has issued a statement about their stance on the “official” naming process. The IAU says that while they welcome the public’s interest in being involved in recent discoveries, as far as they are concerned, the IAU has the last word.

“In the light of recent events, where the possibility of buying the rights to name exoplanets has been advertised, the International Astronomical Union (IAU) wishes to inform the public that such schemes have no bearing on the official naming process. The IAU… would like to strongly stress the importance of having a unified naming procedure,” said the statement issued by the IAU.

Scientist Alan Stern, principal investigator of the New Horizons mission to Pluto and CEO Uwingu told Universe Today that he thinks the IAU should side with democracy instead of elitism.

“I think it is diminishing that the IAU is holding onto their claim that they own the Universe,” he said via phone after reviewing the IAU’s statement. “This is like some 15th century European academic club claiming that since Columbus discovered America, they own all the naming rights. That’s BS.”

While the IAU provides official names for stars and planetary bodies in our Solar System, the IAU’s official stance on naming exoplanets has been that since there is seemingly going to be so many of them, (over 800 have been discovered so far) that it will be difficult to name them all. They’ve said the consensus among IAU scientists was that they had no interest in naming exoplanets.

However, they recently added a few sentences on their website that “the IAU greatly appreciates and wishes to acknowledge the increasing interest from the general public in being more closely involved in the discovery and understanding of our Universe. As a result in 2013 the IAU Commission 53 Extrasolar Planets and other IAU members will be consulted on the topic of having popular names for exoplanets, and the results will be made public on the IAU website.”

Stern thinks the IAU’s current stance on naming exoplanets is tactical mistake. “The taxpaying public pays for all the exploration that the IAU members are doing, but the IAU is making an attempt to limit the public’s involvement in something that the public clearly likes to do,” he said. “As an astronomer, that’s my view.”

Uwingu, a startup company that is using out-of-the-box ideas to raise funds for space exploration and science, started an exoplanet naming contest last fall, and the contest to provide a better, “snappier” name for ACBb was started in March, 2013.

Stern knew going into this that the names wouldn’t officially be approved by the International Astronomical Union, but said they will be similar to the names given to features on Mars by the mission science teams (such as Mt. Sharp on Mars –the IAU-approved name is Aeolis Mons) or even like Pike’s Peak, a mountain in Colorado which was named by the public, in a way, as early settlers started calling it that, and it soon became the only name people recognized.

“This should be the wave of the future for planets and there’s no reason for the public not to get involved,” Stern said.

In today’s statement, the IAU said the “certificates” people receive after suggesting a name in Uwingu’s contest are “misleading, as these campaigns have no bearing on the official naming process — they will not lead to an officially-recognized exoplanet name, despite the price paid or the number of votes accrued.”

The IAU conceded that while exoplanet names such as 16 Cygni Bb or HD 41004 Ab may seem boring compared to the names of planets in our own Solar System, “the vast number of objects in our Universe — galaxies, stars, and planets to name just a few — means that a clear and systematic system for naming these objects is vital. Any naming system is a scientific issue that must also work across different languages and cultures in order to support collaborative worldwide research and avoid confusion.”

And to make that possible, the IAU should act as a single arbiter of the naming process, they said.

“As an international scientific organization, [the IAU] dissociates itself entirely from the commercial practice of selling names of planets, stars or or even “real estate” on other planets or moons. These practices will not be recognized by the IAU and their alternative naming schemes cannot be adopted.”

Information about Alpha Centauri Bb. Information about Alpha Centauri Bb. Credit: Planetary Habitability Laboratory/University of Puerto Rico/Arecibo
Information about Alpha Centauri Bb. Information about Alpha Centauri Bb. Credit: Planetary Habitability Laboratory/University of Puerto Rico/Arecibo

However, several astronomers, including Xavier Dumusque, the lead author of the paper that announced the discovery of ACBb has said they like the idea of having the public involved in naming the exoplanets.

“I would definitively endorse the name for public outreach and lectures,” Dumusque told Alan Boyle of NBC’s Cosmic Log. “In astronomy, we have some chance to be able to make people dream, by showing a wonderful picture, by discovering new worlds. If someone is interested in astronomy, he should not face troubles to understand all the nomenclature. Therefore, giving memorable names for planets is one way to get more people interested in our wonderful research.”

Moonwalker Buzz Aldrin also has been actively participating in the contest and suggested “Tiber” as the name for ACBb. Aldrin is the co-author of a 1977 sci-fi novel titled “Encounter With Tiber.”

IAU’s reticence in naming exoplanets seems to come from the huge bulk of names that will be required. But that’s where Uwingu’s crowd sourcing idea seems to fit the need, and a sort of compromise would be that the public could come up with the names as suggestions in Uwingu’s “baby book” of names, and the IAU would assign the “official” names from the list provided by the public.

If nothing else, Uwingu’s concept has shown how interested the public is in exoplanets and hopefully has given the IAU the kick in the pants needed to possibly consider naming them.

If you’re interested in suggesting names for ACBb, be quick, as the Uwingu contest ends on April 15.