Friday, March 21st, 2008

Sensing the Atmosphere of Distant Planets

The star HD189733 is shown by the green arrow. It is located less that 0.15° (about half the diameter of the Moon) from the M27 "Dumbell" planetary nebulae. photo by Daniel Jaroschik

Scientists using the Hubble Space Telescope have been able to detect the chemical signature of methane in the atmosphere of a planet orbiting a star 63 light-years away. It's the first detection of an organic molecule around an exoplanet, a planet outside our solar system. The observations also confirmed previous work that detected the presence of water in the atmosphere.

The planet, known as HD189733b, is a 'hot Jovian' type planet, with conditions too harsh to allow any known type of life. "We are really excited about this detection because it is a dress rehearsal for future searches for life on more hospitable planets," said Mark Swain, one of the researchers on the project.

The methane was detected by its chemical signature in the near-infrared transmission spectrum of photons passing from the planet's sun through the edge of the planet's atmosphere. The researchers hope that other instruments, including the James Webb Space Telescope planned to come online in about 5 years, will be able to do similar analysis on more distant planets. Details of the methane observations were published this week in the journal Nature. In this segment, Ira talks with one of the astronomers involved with the project about the work, and what it means to the search for life elsewhere in the universe.

Guests

Mark Swain
Research Scientist
Deputy Director for JPL Exoplanet Center of Excellence
NASA's Jet Propulsion Laboratory
California Institute of Technology
Pasedena, California