National Aeronautics and Space Administration

Spiral signpost of planets

This week, it’s been a feast of exoplanet science at Goddard, which hosted the Signposts of Planets meeting Oct. 18-20. The three-day conference gathered an international crowd of observers, computer modelers, and instrument builders to explore the relationship between exoplanets and the circumstellar disks in which they form.

Circumstellar what?

Circumstellar simply means “disks of gas and dust around a star or stars.” Astronomers have discovered some 687 planets around other stars, but ironically they rarely are able to “see” one directly. What the Hubble telescope and other instruments see are dusty disks.

Circumstellar disks are the “signposts of planets” referenced by the name of the conference. Want to find planets? Look for dusty disks.

Here is Goddard astrophysicist and Signpost meeting organizer Marc Kuchner explaining the lowdown on circumstellar disks, back when we only knew of about 400 extrasolar worlds:



The conference produced some show-stoppers in terms of new discoveries announced. Four were the subject of press releases:

Spiral signposts
At the meeting, Goddard astronomer Carol Grady announced the discovery of a type of exoplanet telltale predicted but never actually imaged before. In some circumstellar disks, the tug of a planet’s gravity can create subtle spiral features in the gas and dust. That is good news, because it means that disks with spirals could lead astronomers to planets.

“What we’re finding is that once these systems reach ages of a few million years, their disks begin to show a wealth of structure — rings, divots, gaps and now spiral features,” said John Wisniewski, a collaborator at the University of Washington in Seattle. “Many of these structures could be caused by planets within the disks.”

The newly imaged disk surrounds SAO 206462, a star located about 456 light-years away in the constellation Lupus.

Baby planet

Baby planet
Also at the conference, astronomer Adam Kraus explained how he used the mammoth Keck telescopes on Mauna Kea in Hawaii to image an infant planet. “LkCa 15 b is the youngest planet ever found, about 5 times younger than the previous record holder,” said Kraus, who is based at the University of Hawaii’s Institute for Astronomy.

Kraus did the work using a technique called interferometry, which allows a telescope to achieve the detail-resolving power equivalent to that of a much larger telescope.

Cool findings
In another report at the Signpost meeting, astronomer Kevin Luhman of Penn State University described his observations of a star with a cool planet-like companion. The object, a gaseous not-quite-a-star called a brown dwarf, has an outer temperature described as comparable to “a hot summer day in Arizona.”

Coolest brown dwarf ever

Luhman commented:

“Its mass is about the same as many of the known extra-solar planets — about six to nine times the mass of Jupiter — but in other ways it is more like a star. Essentially, what we have found is a very small star with an atmospheric temperature about cool as the Earth’s.”

OK, not quite a planet — but not quite a star either. Brown dwarfs lie in between. But they lie along a spectrum of objects that exoplanet researchers study.

Ever since brown dwarfs first were discovered in 1995, astronomers have been trying to find new record holders for the coldest brown dwarfs because these objects are valuable as laboratories for studying the atmospheres of planets with Earth-like temperatures outside our solar system.

Comet storm

And last but not least, comet storms!

NASA’s Spitzer Space Telescope has detected signs of icy bodies raining down in an alien solar system. The downpour resembles our own solar system several billion years ago during a period known as the “Late Heavy Bombardment,” which may have brought water and other life-forming ingredients to Earth.

Carey Lisse, senior research scientist at the Johns Hopkins University Applied Physics Laboratory in Laurel, Maryland., announced the finding at the Signposts conference. The research will be published in the Astrophysical Journal.

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OH AND DID I MENTION? All opinions and opinionlike objects in this blog are mine alone and NOT those of NASA or Goddard Space Flight Center. And while we’re at it, links to websites posted on this blog do not imply endorsement of those websites by NASA.



Here are more than 200 of us at NASA/Goddard watching the Juno Mission blast off to Jupiter. A team of our scientists and engineers built an instrument Juno will use to study Jupiter’s mighty magnetic field.

To learn all the amazing stuff Juno will do when it reaches Jupiter in 5 years, see the excellent and detailed web feature by my friend Liz Zubritsky.



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OH AND DID I MENTION? All opinions and opinionlike objects in this blog are mine alone and NOT those of NASA or Goddard Space Flight Center. And while we’re at it, links to websites posted on this blog do not imply endorsement of those websites by NASA.

Astronomer Heidi Hammel talks about how the Webb Telescope can be used to study our solar system.

The James Webb Space Telescope will look far back in cosmic time to study the origins of the universe.  But that doesn’t mean the observatory will turn a blind eye to the planets. Yesterday, at a conference at the Space Telescope Science Institute (STScI) in Baltimore,  noted planetary astronomer Heidi Hammel gave us a quick tour of the solar system from Webb’s (future) point of view.

UPDATE: A webcast video of Hammel’s talk is now available on the STScI website.

The conference, Frontier Science Opportunities with the James Webb Space Telescope (June 6-8), is all about what Webb can and will do once it makes it into space. It’ll be a while: As Matt Mountain, director of STSciI, mentioned in his opening remarks to the conference, Webb won’t see the cold of space, some 1 million miles from Earth, until at least 2017.

Hammel is known to be a great speaker, and she didn’t disappoint. First she took Mercury, Venus, and Earth out of the lineup. Her Powerpoint slides?

Mercury? No.

Venus? No.

Earth? No.



Webb’s orbit and the size and shape of its sunshield leave these planets in an “exclusion zone” hidden from the observatory’s view. (Its planned orbital perch is a point called L2, opposite from Earth with respect to the sun.) Ok, fine. What about Mars?

Yes. According to a March 9, 2010 White Paper about Webb and the solar system, the observatory could measure a number of important things in Mars’ atmosphere, like dust and carbon dioxide gas, that affect its climate.

Hammel speculated that Webb’s infrared eyes could help solve the mysterious nature of methane releases observed on Mars. Where does the methane come from? Webb might help us figure it out.

Jupiter? Saturn? Yes, yes. There is much Webb could learn about the atmospheres of these giant gas planets — which are, by the way, the best nearby examples we have of the scores of giant gaseous exoplanets being discovered in other solar systems.

Titan, Saturn’s largest moon? Yes. Webb could add a decade of observations of Titan’s surface and atmosphere to the work of the Cassini orbiter, and during a time in Titan’s seasonal cycle not yet explored in the infrared band, according to the White Paper.

Uranus and Neptune? An enthusiastic thumbs up from Hammel to the idea of studying these cool, distant bodies with the Webb’s infrared camera and spectrographs. She cited several scientific puzzles that Webb might help solve, including shifts in the wavelengths of light emitted by Uranus as the planet rotates and Neptune’s inexplicably warm polar region.

In general, Hammel said, “Neptune’s atmosphere is so dynamic, and little is known.” Anything Webb contributes will be helpful.

Last but not least, the region beyond Neptune, realm of Pluto and the other icy dwarf planets, is also fair game for Webb.  As the White Paper explains:

“Beyond Neptune, a class of cold, large bodies that include Pluto, Triton and Eris exhibits surface deposits of nitrogen, methane, and other molecules that are poorly observed from the ground, but for which JWST might provide spectral mapping at high sensitivity and spatial resolution difficult to match with the current generation of ground-based observatories.”

And comets, too. At least comets slow enough for Webb to track.

There has been much public hand wringing lately over growth in the Webb budget and slips in the launch date. But in the scientific community, two generations eagerly await the lofting of the giant Webb observatory into orbit. Many of them are up at STScI today sharing their plans.

“There’s a lot of great science that’s going to come out of this and I’m really looking forward to it,” Hammel said. “There is a wide range of interesting planetary phenomena observable by JWST, especially in the outer solar system.”

This NASA video goes into detail about planet studies — here and elsewhere in the universe — and the James Webb Space Telescope:



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OH AND DID I MENTION? All opinions and opinionlike objects in this blog are mine alone and NOT those of NASA or Goddard Space Flight Center. And while we’re at it, links to websites posted on this blog do not imply endorsement of those websites by NASA.

In this artist's concept of a tar-covered carbon planet, a meteor impact has exposed a diamond layer in the planet's interior. For permission to reproduce this figure, please contact Lynette R. Cook at lynette@spaceart.org. Credit: Lynette Cook (extrasolar.spaceart.org)

“There is no use trying, said Alice; one can’t believe impossible things. I dare say you haven’t had much practice, said the Queen. When I was your age, I always did it for half an hour a day. Why, sometimes I’ve believed as many as six impossible things before breakfast.”

This just in from our Department of Impossible Things: carbon-soaked planets harboring rock formations glittering with diamonds instead of quartz or other silicate minerals common on Earth. Imagine dark gray plains of graphite. Bubbling pools of tar. A smoggy methane atmosphere.

Scientists today report using the Spitzer Space Telescope to discover the carbon-rich recipe of a previously known exoplanet called WASP-12b. A press release today from Jet Propulsion Laboratory has more details:

“Astronomers have discovered that a huge, searing-hot planet orbiting another star is loaded with an unusual amount of carbon. The planet, a gas giant named WASP-12b, is the first carbon-rich world ever observed. The discovery was made using NASA’s Spitzer Space Telescope, along with previously published ground-based observations.“

Here at Goddard, exoplanet researcher Marc Kuchner received the news with barely concealed glee. In years past, his work contributed to establishing the hypothetical existence of carbon planets. The WASP-12b observations confirm it.

The implications are exotic. Weird things happen when the ratio of carbon to oxygen in a planetary system crosses the tipping point — that being a ratio greater than 1 to 1.

“When the relative amount of carbon gets that high, it’s as though you flip a switch, and everything changes,” Kuchner explains. “Everything would be different — like imagine, one day you’re a Yankees fan, the next day, Red Sox.”

WASP-12b is a gas giant, so its carbon-rich creations swirl within oceans of dense atmosphere. But what about terrestrial (i.e., rocky) carbon planets? Now it gets mighty interesting.

“If something like this had happened on Earth when it was formed,” Kuchner says, “your expensive engagement ring would be made of glass, which would be rare, because the atmosphere would be made of smog and the mountains would all be made of diamonds.”



Artist’s conception of the dust and gas disk surrounding the star Beta Pictoris. A giant planet may have already formed and terrestrial planets may be forming. The inset panels show two possible outcomes for mature terrestrial planets around Beta Pic. The top one is a water-rich planet similar to the Earth; the bottom one is a carbon-rich planet, with a smoggy, methane-rich atmosphere similar to that of Titan, a moon of Saturn. A team led by Aki Roberge of NASA’s Goddard Space Flight Center first presented the observation in the June 8, 2006, issue of Nature. Credit: NASA/FUSE/Lynette Cook


Kuchner says he thought initially carbon planets would probably be found in exotic stellar environs, like planetary systems whirling around pulsars or white dwarf stars. “But WASP 12 seems to be a pretty normal star, similar to the sun. If it could happen there, it could have happened here. And now that we know WASP-12b is a carbon planet. I bet we’ll start finding others.”

Well, that sounds familiar. In the early days of exoplanet discovery, we found “hot Jupiters,” gas giant planets orbiting shockingly close to their host stars. They seemed exotic until we started finding them all over the place. Now it’s “another day, another hot Jupiter.”

So perhaps carbon-rich planets won’t seem so strange someday, too. Case in point: a star called Beta Pictoris. Kuchner says Beta Pic is “mostly quite similar to the sun, but which has a planetary system and a disk around it that’s carbon rich. Not just a little carbon rich. It has nine times as much carbon as oxygen.  That’s even more carbon-rich than WASP-12b.”

We can only imagine what a planet might look like in such a carbon-mad place. We may never know, but it’s fun to wonder. The WASP-12b discovery gives us permission. “People sort of didn’t take the carbon planets idea seriously at first,” Kuchner says, “but this changes things.”


RIGHT:  This image of the circumstellar disk around Beta Pictoris shows (in false colors) the light reflected by dust around the young star at infrared wavelengths. The Beta Pic disk is very likely an infant solar system in the process of forming terrestrial planets. Credit: Jean-Luc Beuzit, et al. Grenoble Observatory, European Southern Observatory
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OH AND DID I MENTION? All opinions and opinionlike objects in this blog are mine alone and NOT those of NASA or Goddard Space Flight Center. And while we’re at it, links to websites posted on this blog do not imply endorsement of those websites by NASA.

gamma blitz

MONDAY JULY 19: A year ago, something hit Jupiter, the Hubble Space Telescope saw it, and Goddard scientists were part of the response.

SPRECHEN SIE GAMMA BLITZ? The website for the German magazine Der Spiegel has produced a cool video — it’s (duh) in German, by the way — about last week’s breaking news about a gamma-ray burst (GRB) that temporarily “blinded” the Swift observatory. In German, a GRB is called a “gamma blitz.” (Yup, they make you first watch a commercial, in German, before the gamma-ray blitz starts.)

AWESOME STATISTIC: The NASA Blueshift Weekly Awesomeness Round-up takes the prize this week for most blogolicious science statistic. NASA scientists helped discovered a black hole with massive jets blasting from its poles. “If the black hole were shrunk to the size of a soccer ball,” scientist Robert Scoria explained, “each jet would extend from the Earth to beyond the orbit of Pluto.”


TUESDAY JULY 20: Today in 1976, NASA’s Viking 1 Lander touched down safely on the surface of Mars. Also, a NASA mission called “Apollo 11″ landed two guys on the moons, whereupon one of them, named Neil Armstrong, went outside to take a giant leap for mankind. . . . The National Aeronautics and Space Administration Facebook page did a lusciously detailed and dramatic series of posts reenacting the mission.

UP FROM THE DEPTHS: The central peak of Aristarchus Crater on the moon has deep origins. Read about it on the Lunar Reconnaissance Orbiter (LROC) Featured Image website.

SLICK OPERATIONS: See the NASA satellite time-lapse video of the Gulf oil spill through July 14, 2010.


HOW HIGH THE FOREST? The NASA Earth Science News Team’s Adam Voiland features a first-of-its kind map of the height of the world’s forests — based on data collected by NASA’s ICESat, Terra, and Aqua satellites.

star power

WEDNESDAY JULY 21: NASA-funded researcher Bo-wen Shen re-runs the formation of the Tropical Cyclone Nargis in a supercomputer. COOL SHIPS: On the What On Earth blog, NASA Earth Science News Team reporter Gretchen Cook-Anderson profiles NASA/Goddard scientist Charles Kironji, who discovered that the wakes of ocean-going ships have a local chilling effect on climate. ATTRACTIVE: Sparkley loopy new shot of our supermagnetic home star from the Solar Dynamics Observatory uploads to the Goddard Flickr site.

booted out

THURSDAY JULY 22: Today in 1962, NASA launched the ill-fated Mariner 1 spacecraft bound for Venus. The vehicle was destroyed by the Range Safety Officer 293 seconds after launch when it veered off course.

GIRLS IN SPACE: Ten Girl Scout teams nationwide, including two girls from Kansas, spent the week at Goddard Space Flight Center in Maryland as part of a NASA’s “Girls in Space” program. . . . This evening, members of the Goddard Astronomy Club held a special star party for the Scouts at the Visitor Center, featuring the moon, Venus, Saturn, and summer constellations.

COSMIC COOKERY: A new video explains how a powerful instrument called a mass spectrometer figures out the recipe of the universe.

FROZEN FLOW: NASA Earth Science News Team writer Kathryn Hansen reports on the Antarctic Surface Accumulation and Ice Discharge (ASAID) project. The project is making a new map of the “grounding line” where ice breaks off into the ocean.

AND STAY OUT! NASA’s Hubble Space Telescope has detected two stars being tossed out of the Milky Way Galaxy.

FRIDAY JULY 23: The historic Landsat 1 satellite launched this day in 1972. Images from Landsat 1 demonstrated the usefulness of remote sensing data for land surveys, land management, water resource planning, agricultural forecasting, forest management, sea ice movement, and cartography.

HOT LINKS: The University of Virginia Engineering Department’s E-News Online for July profiles Alexandra Hoeft (Engr Sci, Math’11), a spring 2010 intern with NASA Undergraduate Student Research Program (USRP). Hoeft worked for 15 weeks at NASA Goddard Space Flight Center in Greenbelt, Maryland, with NASA mentor Stephen Waterbury. _____________________________________________________________________________________________________ OH AND DID I MENTION? All opinions and opinionlike objects in this blog are mine alone and NOT those of NASA or Goddard Space Flight Center. And while we’re at it, links to websites posted on this blog do not imply endorsement of those websites by NASA.