National Centre of Competence in Research | PlanetS | 2015 Apr 13
Studying the atmosphere of an exoplanet, astronomers of the NCCR PlanetS derived a temperature profile with unprecedented precision. Their results are based on data collected with a relatively small ground-based telescope. This opens completely new perspectives for the characterization of remote exoplanetary atmospheres.The temperature in the atmosphere of HD189733b increases with altitude.
Credit: Observatoire de Genève/NASA/ESA
High up in the atmosphere of the exoplanet named HD 189733b it is several thousand degrees hot. This gas-giant is located 63 light-years or 600 trillion kilometres away from Earth in the constellation Vulpecula (the “little fox”). The temperature is increasing with altitude and reaches more than 3000 degrees Celsius, enough to melt iron, and is much in excess of the planet equilibrium temperature. “This is a sign that heating takes place at high altitudes in the planetary atmosphere”, explains Aurélien Wyttenbach, a PhD student at Geneva Observatory. Besides deriving a temperature profile of the planetary atmosphere, the Geneva team found tantalising evidence of high-altitude winds blowing from the exoplanet’s hot day side to the cold night side with speeds of several kilometres per second – “also an unprecedented detection”, adds Wyttenbach.
The results based on observations with a ground-based telescope in Chile are supported by a theoretical study by Kevin Heng, a professor and astrophysicist at the University of Bern, who is coining new diagnostics for planetary atmospheres. These two studies are the outcome of a collaboration between the Universities of Geneva and Bern under a Swiss-wide framework for planetary and exoplanetary science known as “PlanetS” that also includes ETH Zurich and the University of Zurich. ...
Spectrally resolved detection of sodium in the atmosphere of HD189733b with the HARPS spectrograph - Aurélien Wyttenbach et al
- Astronomy & Astrophysics (accepted 14 Mar 2015) DOI: 10.1051/0004-6361/201525729
arXiv.org > astro-ph > arXiv:1503.05581 > 18 Mar 2015
- Astrophysical Journal Letters 803(1) L9 (10 Apr 2015) DOI: 10.1088/2041-8205/803/1/L9
arXiv.org > astro-ph > arXiv:1503.05582 > 18 Mar 2015