TY - JOUR
T1 - Ground-based transit observations of the super-Earth GJ 1214 b
AU - Cáceres, C.
AU - Kabath, P.
AU - Hoyer, S.
AU - Ivanov, V. D.
AU - Rojo, P.
AU - Girard, J. H.
AU - Miller-Ricci Kempton, E.
AU - Fortney, J. J.
AU - Minniti, D.
N1 - Funding Information:
The authors are grateful to the SOAR and the ESO staff for the help during the observations. The SOI observations were performed thanks to granted Director’s Discretionary Time of the SOAR Telescope. C.C. acknowledges support from ALMA-CONICYT Fund through grant 31100025 and project CONICYT FONDECYT Postdoctorado 3140592. SH and PR would like to acknowledge grant FONDECYT 1120299. S.H. also acknowledges financial support from the Spanish Ministry of Economy and Competitiveness (MINECO) under the 2011 Severo Ochoa Program MINECO SEV-2011-0187. P.K. acknowledges co-funding under the Marie Curie Actions of the European Commission (FP7-COFUND) and the MCMC code kindly provided by Michäel Gillon (University of Liège). D.M. thanks Basal-CATA PFB-06.
PY - 2014/5
Y1 - 2014/5
N2 - Context. GJ 1214 b is one of the few known transiting super-Earth-sized exoplanets with a measured mass and radius. It orbits an M-dwarf, only 14.55? pc away, making it a favorable candidate for follow-up studies. However, the composition of GJ? 1214? b's mysterious atmosphere has yet to be fully unveiled. Aims. Our goal is to distinguish between the various proposed atmospheric models to explain the properties of GJ? 1214? b: hydrogen-rich or hydrogen-He mix, or a heavy molecular weight atmosphere with reflecting high clouds, as latest studies have suggested. Methods. Wavelength-dependent planetary radii measurements from the transit depths in the optical/NIR are the best tool to investigate the atmosphere of GJ? 1214? b. We present here (i) photometric transit observations with a narrow-band filter centered on 2.14? μm and a broad-band I-Bessel filter centered on 0.8665? μm, and (ii) transmission spectroscopy in the H and K atmospheric windows that cover three transits. The photometric and spectrophotometric time series obtained were analyzed with MCMC simulations to measure the planetary radii as a function of wavelength. We determined radii ratios of 0.1173-0.0024+0.0022 for I-Bessel and 0.11735-0.00076+0.00072 at 2.14? μm. Results. Our measurements indicate a flat transmission spectrum, in agreement with the last atmospheric models that favor featureless spectra with clouds and high molecular weight compositions.
AB - Context. GJ 1214 b is one of the few known transiting super-Earth-sized exoplanets with a measured mass and radius. It orbits an M-dwarf, only 14.55? pc away, making it a favorable candidate for follow-up studies. However, the composition of GJ? 1214? b's mysterious atmosphere has yet to be fully unveiled. Aims. Our goal is to distinguish between the various proposed atmospheric models to explain the properties of GJ? 1214? b: hydrogen-rich or hydrogen-He mix, or a heavy molecular weight atmosphere with reflecting high clouds, as latest studies have suggested. Methods. Wavelength-dependent planetary radii measurements from the transit depths in the optical/NIR are the best tool to investigate the atmosphere of GJ? 1214? b. We present here (i) photometric transit observations with a narrow-band filter centered on 2.14? μm and a broad-band I-Bessel filter centered on 0.8665? μm, and (ii) transmission spectroscopy in the H and K atmospheric windows that cover three transits. The photometric and spectrophotometric time series obtained were analyzed with MCMC simulations to measure the planetary radii as a function of wavelength. We determined radii ratios of 0.1173-0.0024+0.0022 for I-Bessel and 0.11735-0.00076+0.00072 at 2.14? μm. Results. Our measurements indicate a flat transmission spectrum, in agreement with the last atmospheric models that favor featureless spectra with clouds and high molecular weight compositions.
KW - Planetary systems
KW - Planets and satellites: atmospheres
KW - Stars: individual: GJ 1214
KW - Techniques: photometric
KW - Techniques: spectroscopic
UR - http://www.scopus.com/inward/record.url?scp=84898779795&partnerID=8YFLogxK
U2 - 10.1051/0004-6361/201321087
DO - 10.1051/0004-6361/201321087
M3 - Article
AN - SCOPUS:84898779795
SN - 0004-6361
VL - 565
JO - Astronomy and Astrophysics
JF - Astronomy and Astrophysics
M1 - A7
ER -