Optical Observations of the Transiting Exoplanet GJ 1214b

Abstract

We observed nine primary transits of the super-Earth exoplanet GJ 1214b in several optical photometric bands from March to August 2012, with the goal of constraining the short-wavelength slope of the spectrum of GJ 1214b. Our observations were conducted on the Kuiper 1.55 m telescope in Arizona and the STELLA-I robotic 1.2 m telescope in Tenerife, Spain. From the derived light curves we extracted transit depths in R (0.65 μm), V (0.55 μm), and g' (0.475 μm) bands. Most previous observations of this exoplanet suggest a flat spectrum varying little with wavelength from the near-infrared to the optical, corresponding to a low-scale-height, high-molecular-weight atmosphere. However, a handful of observations around Ks band (~2.15 μm) and g-band (~0.46 μm) are inconsistent with this scenario and suggest a variation on a hydrogen- or water-dominated atmosphere that also contains a haze layer of small particles. In particular, the g-band observations of de Mooij et al. (2012), consistent with Rayleigh scattering, limit the potential atmosphere compositions of GJ 1214b due to the increasing slope at optical wavelengths (Howe & Burrows 2012). We find that our results overlap within errors the short-wavelength observations of de Mooij et al. (2012), but are also consistent with a spectral slope of zero in GJ 1214b in the optical wavelength region. Our observations thus allow for a larger suite of possible atmosphere compositions, including those with a high-molecular-weight and/or hazes.

20 pages, 4 figures, 3 tables. Accepted to MNRAS. Revisions: Updated reference list with 2 additional references; updated Figure 3 with 1 additional source of observations (3 points)

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Cited by in corpus (27)

• How to Distinguish between Cloudy Mini-Neptunes and Water/Volatile-Dominated Super-Earths
• A Framework for Characterizing the Atmospheres of Low-Mass Low-Density Transiting Planets
• Thermal Emission and Albedo Spectra of Super Earths with Flat Transmission Spectra
• Quantitatively Assessing the Role of Clouds in the Transmission Spectrum of GJ 1214b
• ACCESS I: An Optical Transmission Spectrum of GJ 1214b Reveals a Heterogeneous Stellar Photosphere
• Atmospheric dynamics of terrestrial exoplanets over a wide range of orbital and atmospheric parameters
• Ground-based near-UV observations of 15 transiting exoplanets: Constraints on their atmospheres and no evidence for asymmetrical transits
• Microphysics of KCl and ZnS Clouds on GJ 1214b
• Disentangling degenerate solutions from primary transit and secondary eclipse spectroscopy of exoplanets
• The Hazy and Metal-Rich Atmosphere of GJ 1214 b Constrained by Near and Mid-Infrared Transmission Spectroscopy
• The atmospheric circulation of the super Earth GJ 1214b: Dependence on composition and metallicity
• Constraints on Planet Occurrence around Nearby Mid-to-Late M Dwarfs from the MEarth Project
• Search for a habitable terrestrial planet transiting the nearby red dwarf GJ 1214
• Multi-Color Transit Photometry of GJ 1214b through BJHKs-Bands and a Long-Term Monitoring of the Stellar Variability of GJ 1214
• GJ1214: Rotation period, starspots, and uncertainty on the optical slope of the transmission spectrum
• Investigating the physical properties of transiting hot Jupiters with the 1.5-m Kuiper Telescope
• Photometric observation of HAT-P-16b in the near-UV
• Narrow-K-Band Observations of the GJ 1214 System
• Large Binocular Telescope view of the atmosphere of GJ1214b
• Broad-band spectrophotometry of HAT-P-32 b: Search for a scattering signature in the planetary spectrum
• Search for Rayleigh scattering in the atmosphere of GJ1214b
• Ground-based transit observations of the super-Earth GJ 1214b
• Transmission spectroscopy of the hot Jupiter TrES-3 b: Disproof of an overly large Rayleigh-like feature
• Using near infra-red spectroscopy for characterization of transiting exoplanets
• Not All Sub-Neptune Exoplanets Have Magma Oceans
• Model-independent exoplanet transit spectroscopy
• Simultaneous multicolour optical and near-IR transit photometry of GJ 1214b with SOFIA