For the first time a clever new technique has allowed astronomers to study the atmosphere of an exoplanet in detail — even though it does not pass in front of its parent star. An international team has used ESO’s Very Large Telescope to directly catch the faint glow from the planet Tau Boötis b. They have studied the planet’s atmosphere and measured its orbit and mass precisely for the first time — in the process solving a 15-year old problem. Surprisingly, the team also finds that the planet’s atmosphere seems to be cooler higher up, the opposite of what was expected. The results were published in the 28 June 2012 issue of the journal Nature.
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| This artist’s impression shows the exoplanet Tau Boötis b. This was one of the first exoplanets to be discovered back in 1996, and it is still one of the closest planetary systems known to date. Astronomers using ESO’s Very Large Telescope have now caught and studied the faint light from the planet Tau Boötis b for the first time. By employing a clever observational trick the team find that the planet’s atmosphere seems to be cooler higher up, the opposite of what was expected. Credit: ESO/L. Calçada |
