Exoplanets & Exomoons

Variability in the Super-Earth 55 Cnc e

By Keith Cowing
Status Report
May 4, 2015
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Variability in the Super-Earth 55 Cnc e
This artist’s impression shows the super-Earth 55 Cancri e in front of its parent star. Using observations made with the NASA/ESA Hubble Space Telescope and new analytic software scientists were able to analyse the composition of its atmosphere. It was the first time this was possible for a super-Earth. 55 Cancri e is about 40 light-years away and orbits a star slightly smaller, cooler and less bright than our Sun. As the planet is so close to its parent star, one year lasts only 18 hours and temperatures on the surface are thought to reach around 2000 degrees Celsius.

Considerable progress has been made in recent years in observations of atmospheric signatures of giant exoplanets, but processes in rocky exoplanets remain largely unknown due to major challenges in observing small planets.

Numerous efforts to observe spectra of super-Earths, exoplanets with masses of 1-10 Earth masses, have thus far revealed only featureless spectra. In this paper we report a 4-σ detection of variability in the dayside thermal emission from the transiting super-Earth 55 Cancri e. Dedicated space-based monitoring of the planet in the mid-infrared over eight eclipses revealed the thermal emission from its dayside atmosphere varying by a factor 3.7 between 2012 and 2013.

The amplitude and trend of the variability are not explained by potential influence of star spots or by local thermal or compositional changes in the atmosphere over the short span of the observations. The possibility of large scale surface activity due to strong tidal interactions possibly similar to Io, or the presence of circumstellar/circumplanetary material appear plausible and motivate future long-term monitoring of the planet.

Brice-Olivier Demory, Michael Gillon, Nikku Madhusudhan, Didier Queloz
(Submitted on 1 May 2015)
Comments: Submitted to MNRAS on 10 March 2015. 13 pages, 12 figures, 6 tables
Subjects: Earth and Planetary Astrophysics (astro-ph.EP)
Cite as: arXiv:1505.00269 [astro-ph.EP] (or arXiv:1505.00269v1 [astro-ph.EP] for this version)
Submission history
From: Brice-Olivier Demory
[v1] Fri, 1 May 2015 20:00:54 GMT (274kb)

Explorers Club Fellow, ex-NASA Space Station Payload manager/space biologist, Away Teams, Journalist, Lapsed climber, Synaesthete, Na’Vi-Jedi-Freman-Buddhist-mix, ASL, Devon Island and Everest Base Camp veteran, (he/him) 🖖🏻