David Kirkpatrick

December 10, 2008

CO2 on extrasolar planet

Exciting news in the search for life beyond our atmosphere.

The release:

Hubble finds carbon dioxide on an extrasolar planet

The NASA/ESA Hubble Space Telescope’s international team of researchers has discovered carbon dioxide in the atmosphere of a planet orbiting another star. This is an important step along the trail of finding the chemical biotracers of extraterrestrial life, as we know it. These findings have been published in the Astrophysical Journal Letters, 9 December 2008.

The Jupiter-sized planet, called HD 189733b, is too hot for life. But new Hubble observations are a proof-of-concept demonstration that the basic chemistry for life can be measured on planets orbiting other stars. Organic compounds can also be a by-product of life processes and their detection on an Earth-like planet may someday provide the first evidence of life beyond Earth.

Previous observations of HD 189733b by Hubble and the Spitzer Space Telescope found water vapour. Earlier this year Hubble found methane in the planet’s atmosphere.

“This is exciting because Hubble is allowing us to see molecules that probe the conditions, chemistry, and composition of atmospheres on other planets,” says Mark Swain of The Jet Propulsion Laboratory in Pasadena, USA. “Thanks to Hubble we’re entering an era where we are rapidly going to expand the number of molecules we know about on other planets.”

Swain and team used Hubble’s Near Infrared Camera and Multi-Object Spectrometer (NICMOS) to study infrared light emitted from the planet, which lies 63 light-years away. Gases in the planet’s atmosphere absorb certain wavelengths of light from the planet’s hot glowing interior. They identified not only carbon dioxide, but also carbon monoxide. The molecules leave their own unique spectral fingerprint on the radiation from the planet that reaches Earth. This is the first time a near-infrared emission spectrum has been obtained for an extrasolar planet.

“The carbon dioxide is kind of the main focus of the excitement, because that is a molecule that under the right circumstances could have a connection to biological activity as it does on Earth,” Swain says. “The very fact that we’re able to detect it, and estimate its abundance, is significant for the long-term effort of characterizing planets both to find out what they’re made of and to find out if they could be a possible host for life.”

Co-researcher, the UK’s Dr Giovanna Tinetti of the University College London, who holds a prestigious Aurora Fellowship at the Science and Technology Facilities Council (STFC) says: “In the terrestrial planets of our solar system, CO2 plays a crucial role in the stability of climate. On Earth, CO2 is one of the ingredients of the photosynthesis and a key element for the carbon cycle. Our observations represent a great opportunity to understand the role of CO2 in the atmospheres of hot-gaseous and highly irradiated planets”.

This type of observation is best done for planets with orbits tilted edge-on to Earth. They routinely pass in front of and then behind their parent stars, phenomena known as eclipses. The planet HD 189733b passes behind its companion star once every 2.2 days. This allows an opportunity to subtract the light of the star alone (when the planet is blocked) from that of the star and planet together prior to eclipse), thus isolating the emission of the planet alone and making possible a chemical analysis of its “day-side” atmosphere.

In this way, Swain explains that he’s using the eclipse of the planet behind the star to probe the planet’s day side, which contains the hottest portions of its atmosphere. “We’re starting to find the molecules and to figure out how many of them there are to see the changes between the day side and the night side,” Swain says.

This successful demonstration of looking at near-infrared light emitted from a planet is very encouraging for astronomers planning to use the NASA/ESA/CSA James Webb Space Telescope when it is launched in 2013. These biomarkers are best seen at near-infrared wavelengths.

Astronomers look forward to using JWST to spectroscopically look for biomarkers on a terrestrial planet the size of Earth, or a “super-Earth” several times our planet’s mass. “The Webb telescope should be able to make much more sensitive measurements of these primary and secondary eclipse events,” Swain says.

Swain next plans to search for molecules in the atmospheres of other extrasolar planets, as well as trying to increase the number of molecules detected in extrasolar planet atmospheres. He also plans to use molecules to study changes that may be present in extrasolar planet atmospheres to learn something about the weather on these distant worlds.



November 13, 2008

Hubble directly sees extrasolar planet

Sorry about the release dump today, but I haven’t done one in a while and this just hit the inbox and was way, way too cool to pass up passing it along.

The release:

Hubble Directly Observes A Planet Orbiting Another Star

WASHINGTON, Nov. 13 /PRNewswire-USNewswire/ — NASA’s Hubble Space Telescope has taken the first visible-light snapshot of a planet circling another star.

(Logo: http://www.newscom.com/cgi-bin/prnh/20081007/38461LOGO)

Estimated to be no more than three times Jupiter’s mass, the planet, called Fomalhaut b, orbits the bright southern star Fomalhaut, located 25 light-years away in the constellation Piscis Australis, or the “Southern Fish.”

Fomalhaut has been a candidate for planet hunting ever since an excess of dust was discovered around the star in the early 1980s by NASA’s Infrared Astronomy Satellite, IRAS.

In 2004, the coronagraph in the High Resolution Camera on Hubble’s Advanced Camera for Surveys produced the first-ever resolved visible-light image of the region around Fomalhaut. It clearly showed a ring of protoplanetary debris approximately 21.5 billion miles across and having a sharp inner edge.

This large debris disk is similar to the Kuiper Belt, which encircles the solar system and contains a range of icy bodies from dust grains to objects the size of dwarf planets, such as Pluto.

Hubble astronomer Paul Kalas, of the University of California at Berkeley, and team members proposed in 2005 that the ring was being gravitationally modified by a planet lying between the star and the ring’s inner edge.

Circumstantial evidence came from Hubble’s confirmation that the ring is offset from the center of the star. The sharp inner edge of the ring is also consistent with the presence of a planet that gravitationally “shepherds” ring particles. Independent researchers have subsequently reached similar conclusions.

Now, Hubble has actually photographed a point source of light lying 1.8 billion miles inside the ring’s inner edge. The results are being reported in the November 14 issue of Science magazine.

“Our Hubble observations were incredibly demanding. Fomalhaut b is 1 billion times fainter than the star. We began this program in 2001, and our persistence finally paid off,” Kalas says.

“Fomalhaut is the gift that keeps on giving. Following the unexpected discovery of its dust ring, we have now found an exoplanet at a location suggested by analysis of the dust ring’s shape. The lesson for exoplanet hunters is ‘follow the dust,'” said team member Mark Clampin of NASA’s Goddard Space Flight Center in Greenbelt, Md.

Observations taken 21 months apart by Hubble’s Advanced Camera for Surveys’ coronagraph show that the object is moving along a path around the star, and is therefore gravitationally bound to it. The planet is 10.7 billion miles from the star, or about 10 times the distance of the planet Saturn from our sun.

The planet is brighter than expected for an object of three Jupiter masses. One possibility is that it has a Saturn-like ring of ice and dust reflecting starlight. The ring might eventually coalesce to form moons. The ring’s estimated size is comparable to the region around Jupiter and its four largest orbiting satellites.

Kalas and his team first used Hubble to photograph Fomalhaut in 2004, and made the unexpected discovery of its debris disk, which scatters Fomalhaut’s starlight. At the time they noted a few bright sources in the image as planet candidates. A follow-up image in 2006 showed that one of the objects is moving through space with Fomalhaut but changed position relative to the ring since the 2004 exposure. The amount of displacement between the two exposures corresponds to an 872-year-long orbit as calculated from Kepler’s laws of planetary motion.

Future observations will attempt to see the planet in infrared light and will look for evidence of water vapor clouds in the atmosphere. This would yield clues to the evolution of a comparatively newborn 100-million-year-old planet. Astrometric measurements of the planet’s orbit will provide enough precision to yield an accurate mass.

NASA’s James Webb Space Telescope, scheduled to launch in 2013 will be able to make coronagraphic observations of Fomalhaut in the near- and mid-infrared. Webb will be able to hunt for other planets in the system and probe the region interior to the dust ring for structures such as an inner asteroid belt. For more information about the Hubble Space Telescope, visit:


Photo:  http://www.newscom.com/cgi-bin/prnh/20081007/38461LOGO
AP Archive:  http://photoarchive.ap.org/
PRN Photo Desk photodesk@prnewswire.com
Source: NASA

Web Site:  http://www.nasa.gov/

September 22, 2008

Photo of an extrasolar planet?

Filed under: Media, Science — Tags: , , , — David Kirkpatrick @ 12:56 pm

From KurzweilAI.net — Did University of Toronto astronomers capture an image of an extrasolar planet? You be the judge.

A Maybe Planet, Orbiting Its Maybe Sun
New York Times, Sep. 18, 2008

Astronomers from the University of Toronto have published a picture of what they say might be the first image of a planet orbiting another Sunlike star, about 30 billion miles away from the star, inexplicably.

(Gemini Observatory)
Read Original Article>>