This is a crucial step in the search for extraterrestrial life! A research team led by the University of Bern has created for the first time ever an exoplanet cloud map from Kepler 7b.
An international team, with participation from the University of Bern, has produced the first map of clouds on an exoplanet using the Kepler Space Telescope. Studying the atmospheres of exoplanets is the path towards ultimately identifying life elsewhere in the Universe. Understanding the role of clouds in exoplanet atmospheres is a necessary ingredient in the cosmic hunt for life.
The planet Kepler 7b is located outside our solar system and orbits a Sun-like star in the constellation Lyra. This exoplanet was discovered by the Kepler space telescope only three years ago. An unusual property of Kepler-7b is that it is unusually reflective to starlight: it reflects about 50% of the visible light incident upon its atmosphere.
Why this reflection you may ask you. It is pretty easy to answer: Kepler 7b is surrounded by light-reflecting clouds. This is an important step to learn more about the influence of clouds on the atmospheres of exoplanets. Such knowledge is a prerequisite in the search for extraterrestrial life.
Clouds soon no longer an obstacle in the search for habitable planets
Many exoplanet researchers try to learn how the light spectrum of the atmosphere of an exoplanet could be affected by the presence of life. However, clouds are in the atmosphere and thus may interfere and with measurements such that results cane be difficult to interpret. Insights about the clouds themselves help to take into account their impact on values.
The team measured reflected starlight for the entire orbit of Kepler-7b around its star, much like how one would measure the different phases of the Moon orbiting Earth, producing a “phase curve”, which can be directly transformed into a crude map (with only east-west information). The unexpected structure present in the map, together with the unusually high reflectivity of the atmosphere, implied the existence of clouds. An analysis of the map structure also set constraints on the size of the cloud particles. This first measurement of a map of clouds was published in the Astrophysical Journal Letters (Demory et al. 2013). Another paper demonstrating the unusual reflectivity of Kepler-7b, compared to its peers, was published in the Astrophysical Journal (Heng & Demory 2013).
And yes, with increasing knowledge about exoplanet clouds and atmospheres we will find out whether some of these celestial bodies are life-friendly.
Information on studies
Brice-Olivier Demory, Julien de Wit, Nikole Lewis, Jonathan Fortney, Andras Zsom, Sara Seager, Heather Knutson, Kevin Heng, Nikku Madhusudhan, Michael Gillon, Thomas Barclay, Jean-Michel Desert, Vivien Parmentier, Nicolas B. Cowan: Inference of Inhomogeneous Clouds in to exoplanet atmosphere , Astrophysical Journal Letters, XY, September 2013, in press.
Kevin Heng, Brice Oliver Demory: Understanding trends associated with clouds in irradiated exoplanets , Astrophysical Journal, XY, September 2013, in press.