Astronomers from Japan using NAOJ’s Subaru Telescope have found that the extrasolar planet Gliese 1214b has a water-rich atmosphere.

Discovered in 2009 by the MEarth Project, this alien world is about 2.7 times Earth’s diameter and is almost 7 times as massive. It is located 42 light years away in the constellation Ophiuchus.

Dr Michitoshi Yoshida of Hiroshima University and his colleagues used the Suprime-Cam and the FOCAS optical camera aboard the Subaru Telescope to look for the Rayleigh scattering feature in the atmosphere of Gliese 1214b.

The new observations, reported in the Astrophysical Journal (arXiv.org), showed that the exoplanet’s atmosphere does not display strong Rayleigh scattering.

According to the astronomers, this finding implies that Gliese 1214b has a water-rich or a hydrogen-dominated atmosphere with extensive clouds.

Although they did not completely discount the possibility of a hydrogen-dominated atmosphere, the new results combined with findings from previous research suggest that Gliese 1214b is likely to have a water-rich atmosphere.

Dr Yoshida’ team now plans to conduct follow-up observations in the near future to reinforce their conclusion.

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Bibliographic information: Norio Narita et al. 2013. Multi-color Transit Photometry of GJ 1214b through BJHK s Bands and a Long-term Monitoring of the Stellar Variability of GJ 1214. ApJ 773, 144; doi: 10.1088/0004-637X/773/2/144