OBSERVATIONAL EVIDENCE FOR A METAL-RICH ATMOSPHERE ON THE SUPER-EARTH GJ1214b

2011/03/11 by Jean-Michel Désert, Jacob Bean, Eliza M.-R. Kempton +9 · 5 citations
Physics and Astronomy · #Astrobiology #Astronomy #Astronomy and Astrophysical Research #Astrophysics #Astrophysics and Star Formation Studies #Atmosphere (unit) #Exoplanet #Light curve #Meteorology #Observatory #Physics #Planet #Spitzer Space Telescope #Stars #Stellar, planetary, and galactic studies #Super-Earth #Telescope #Transit (satellite) #Very Large Telescope #astro-ph.EP

paper · pdf · doi:10.1088/2041-8205/731/2/l40

Accepted for publication in ApJL. 13 pages, 3 figures, 1 table

arxiv created 2011/03/11 · openalex publication_date 2011/04/01 · arxiv updated 2015/05/27 · openalex created_date 2016/06/24 · openalex updated_date 2026/08/05

Abstract

We report observations of two consecutive transits of the warm super-Earth exoplanet GJ 1214b at 3.6 and 4.5 μm with the Infrared Array Camera instrument on board the Spitzer Space Telescope . The two transit light curves allow for the determination of the transit parameters for this system. We find these parameters to be consistent with the previously determined values and no evidence for transit timing variations. The main investigation consists of measuring the transit depths in each bandpass to constrain the planet's transmission spectrum. Fixing the system scale and impact parameters, we measure R p / R ⋆ = 0.1176 +0.0008 −0.0009 and 0.1163 +0.0010 −0.0008 at 3.6 and 4.5 μm, respectively. Combining these data with the previously reported MEarth Observatory measurements in the red optical allows us to rule out a cloud-free, solar composition (i.e., hydrogen-dominated) atmosphere at 4.5σ confidence. This independently confirms a recent finding that was based on a measurement of the planet's transmission spectrum using the Very Large Telescope (VLT). The Spitzer , MEarth , and VLT observations together yield a remarkably flat transmission spectrum over the large wavelength domain spanned by the data. Consequently, cloud-free atmospheric models require more than 30% metals (assumed to be in the form of H 2 O) by volume to be consistent with all the observations.

Citations

• THREE POSSIBLE ORIGINS FOR THE GAS LAYER ON GJ 1214b
• THE ATMOSPHERIC SIGNATURES OF SUPER-EARTHS: HOW TO DISTINGUISH BETWEEN HYDROGEN-RICH AND HYDROGEN-POOR ATMOSPHERES
• Mass‐Radius Relationships for Solid Exoplanets
• THE NATURE OF THE ATMOSPHERE OF THE TRANSITING SUPER-EARTH GJ 1214b
• Detection of an Extrasolar Planet Atmosphere
• The Spitzer Space Telescope Mission
• A super-Earth transiting a nearby low-mass star
• Detection of Thermal Emission from an Extrasolar Planet
• The effect of red noise on planetary transit detection

Cited by

• The effect of metallicity on the atmospheres of exoplanets with fully coupled 3D hydrodynamics, equilibrium chemistry, and radiative transfer
• Temperate Super-Earths/Mini-Neptunes around M/K Dwarfs Consist of Two Populations Distinguished by Kepler and Spitzer Transit Depth Variations
• Optical observations of the transiting exoplanet GJ 1214b
• Near-infrared transmission spectrum of the warm-Uranus GJ 3470b with the Wide Field Camera-3 on theHubbleSpace Telescope
• Exoplanetary Atmospheres—Chemistry, Formation Conditions, and Habitability