Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Extrasolars' light guides atmosphere research

22.02.2007
So far, astronomers have discovered about 200 planets outside our solar system, known as "extrasolar" planets. Very little is known about most of them, but for the first time, scientists have obtained new information about the atmospheres of two such planets by splitting apart the light emitted from them.

Sara Seager, MIT associate professor of earth, atmospheric and planetary sciences, is part of a research group based at Goddard Space Flight Center that studied a planet about 904 trillion miles from Earth, known as HD 209458b. The researchers used NASA's Spitzer Space Telescope to capture the most detailed information yet about an extrasolar planet.

Seager's team is one of three that are reporting spectral observations of extrasolar planets this week. Two groups studied HD 209458b, and one studied another planet in a different solar system. The work by Seager's team is reported in the Feb. 22 issue of Nature.

Astronomers often learn about distant objects, such as stars and galaxies, by studying the composition of light emitted by them, Seager said. But extrasolar planets are much dimmer than stars and thus far more difficult to study.

Light from extrasolar planets is "very, very hard to measure because the stars are so bright and the planets are faint. This planet is right at the edge of what we can detect with this telescope," said Seager, who arrived at MIT in January to start a program devoted to studying extrasolar planets.

The study appearing in Nature was led by L. Jeremy Richardson of the Goddard Space Flight Center near Baltimore, Maryland. The three studies mark the first time a telescope has captured enough light to detect traces of molecules in an extrasolar planet's atmosphere.

"This is an amazing surprise," said Spitzer Project Scientist Michael Werner of NASA's Jet Propulsion Laboratory (JPL) in Pasadena, Calif. "We had no idea when we designed Spitzer that it would make such a dramatic step in characterizing exoplanets."

Studying light spectra only works with so-called "transit planets"-planets whose orbits carry them in front of their sun when viewed from our solar system. HD 209458b, discovered in 1999 in the constellation Pegasus, was the first of 14 such planets that have been found.

Only a few of those planets, including HD 209458b, are bright enough for the spectral studies to yield useful data. A research group at Caltech is reporting spectral observations of another such planet, known as HD 189733b. Both planets are classified as "hot Jupiters," meaning they are large and gaseous, like Jupiter.

Temperatures on HD 209458b range from 1100 to 1600 degrees Kelvin, and the star is so close to its sun that it takes only three and a half days to complete its orbit.

From previous observations, scientists already knew that HD 209458b had sodium, hydrogen, helium and carbon in its atmosphere. They also expected it to have water vapor, but the Goddard spectral analysis did not show any signs of water vapor in the atmosphere. Scientists did not find traces of water vapor in the atmosphere of HD 189733b either.

"That doesn't mean water vapor's not there, but it means the atmosphere is behaving differently than expected," Seager said.

The Goddard team's other major finding was evidence of sandy particles known as silicates in the atmosphere of HD 209458b. NASA scientists hypothesize that clouds of those particles could be blocking emissions from water vapors.

Another team that studied HD 209458b, based at JPL obtained similar results.

The Goddard team recorded its data during two eclipses of HD 209458b, each of which lasted for about three hours. By subtracting the light that was emitted by the sun alone from the light of the planet and sun together, the researchers obtained a spectrum of light from the planet itself.

After the infrared light was captured, it was separated into its component wavelengths, the same way a prism diffracts light into a rainbow. Signatures at different wavelengths represent emissions from different chemical compounds present in the atmosphere.

The new results offer hope of finding and analyzing other planets, including smaller, rocky planets like Earth.

"It's very hard to find Earth-like planets because they're too small. But that's the ultimate goal," said Seager.

Seager's team's research was funded by NASA, the Goddard Center for Astrobiology, the Spitzer Theory Program and the Carnegie Institute of Washington.

Written by Anne Trafton, MIT News Office

Elizabeth A. Thomson | MIT News Office
Further information:
http://www.mit.edu/

More articles from Physics and Astronomy:

nachricht A better way to weigh millions of solitary stars
15.12.2017 | Vanderbilt University

nachricht A chip for environmental and health monitoring
15.12.2017 | Friedrich-Alexander-Universität Erlangen-Nürnberg

All articles from Physics and Astronomy >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: First-of-its-kind chemical oscillator offers new level of molecular control

DNA molecules that follow specific instructions could offer more precise molecular control of synthetic chemical systems, a discovery that opens the door for engineers to create molecular machines with new and complex behaviors.

Researchers have created chemical amplifiers and a chemical oscillator using a systematic method that has the potential to embed sophisticated circuit...

Im Focus: Long-lived storage of a photonic qubit for worldwide teleportation

MPQ scientists achieve long storage times for photonic quantum bits which break the lower bound for direct teleportation in a global quantum network.

Concerning the development of quantum memories for the realization of global quantum networks, scientists of the Quantum Dynamics Division led by Professor...

Im Focus: Electromagnetic water cloak eliminates drag and wake

Detailed calculations show water cloaks are feasible with today's technology

Researchers have developed a water cloaking concept based on electromagnetic forces that could eliminate an object's wake, greatly reducing its drag while...

Im Focus: Scientists channel graphene to understand filtration and ion transport into cells

Tiny pores at a cell's entryway act as miniature bouncers, letting in some electrically charged atoms--ions--but blocking others. Operating as exquisitely sensitive filters, these "ion channels" play a critical role in biological functions such as muscle contraction and the firing of brain cells.

To rapidly transport the right ions through the cell membrane, the tiny channels rely on a complex interplay between the ions and surrounding molecules,...

Im Focus: Towards data storage at the single molecule level

The miniaturization of the current technology of storage media is hindered by fundamental limits of quantum mechanics. A new approach consists in using so-called spin-crossover molecules as the smallest possible storage unit. Similar to normal hard drives, these special molecules can save information via their magnetic state. A research team from Kiel University has now managed to successfully place a new class of spin-crossover molecules onto a surface and to improve the molecule’s storage capacity. The storage density of conventional hard drives could therefore theoretically be increased by more than one hundred fold. The study has been published in the scientific journal Nano Letters.

Over the past few years, the building blocks of storage media have gotten ever smaller. But further miniaturization of the current technology is hindered by...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

See, understand and experience the work of the future

11.12.2017 | Event News

Innovative strategies to tackle parasitic worms

08.12.2017 | Event News

AKL’18: The opportunities and challenges of digitalization in the laser industry

07.12.2017 | Event News

 
Latest News

Engineers program tiny robots to move, think like insects

15.12.2017 | Power and Electrical Engineering

One in 5 materials chemistry papers may be wrong, study suggests

15.12.2017 | Materials Sciences

New antbird species discovered in Peru by LSU ornithologists

15.12.2017 | Life Sciences

VideoLinks
B2B-VideoLinks
More VideoLinks >>>