NASAs little telescope detects Earth-like planet

NASA astronomers have successfully demonstrated that little ground-based telescopes can also detect Earth-like planets around other stars.

Washington, Feb 4 : NASA astronomers have successfully demonstrated that little ground-based telescopes can also detect Earth-like planets around other stars.

The scientists developed the new technique by using NASA's relatively small Earth-based infrared telescope to identify an organic molecule in the atmosphere of a Jupiter-sized planet nearly 63 light-years away.

Using a novel calibration method to remove systematic observation errors, they obtained a measurement revealing details of the exoplanet's atmospheric composition and conditions, an unprecedented achievement from an Earth-based observatory.

The surprising new finding comes from a venerable 30-year-old, 3-meter-diameter (10-foot) telescope that ranks 40th among ground-based telescopes - NASA's Infrared Telescope Facility atop Mauna Kea, Hawaii.

According to John Rayner, the NASA Infrared Telescope Facility support scientist who built the SpeX spectrograph used for these measurements, "On some days, we can't even see the Sun with the telescope, and the fact that on other days we can now obtain a spectrum of an exoplanet 63 light-years away is astonishing."

Using the new technique, the astronomers successfully detected carbon dioxide and methane in the atmosphere of HD 189733b with a spectrograph, which splits light into its components to reveal the distinctive spectral signatures of different chemicals.

In the course of their observations, the team found unexpected bright infrared emission from methane that stands out on the day side of HD 189733b.

This could indicate some kind of activity in the planet's atmosphere which could be related to the effect of ultraviolet radiation from the planet's parent star hitting the planet's upper atmosphere, but more detailed study is needed.

"An immediate goal for using this technique is to more fully characterize the atmosphere of this and other exoplanets, including detection of organic and possibly prebiotic molecules like those that preceded the evolution of life on Earth," said Swain.

The new technique promises to further speed the work of studying planet atmospheres by enabling studies from the ground that were previously possible only through a few very high-performance space telescopes.

"Given favorable observing conditions, this work suggests we may be able to detect organic molecules in the atmospheres of terrestrial planets with existing instruments," said lead author Mark Swain, an astronomer at NASA's Jet Propulsion Laboratory, Pasadena, California.

This can allow fast and economical advances in focused studies of exoplanet atmospheres, accelerating our understanding of the growing stable of exoplanets.

ANI