SEARCH FOR RAYLEIGH SCATTERING IN THE ATMOSPHERE OF GJ1214b

Journal Article · Wed Jul 10 00:00:00 EDT 2013 · Astrophysical Journal

DOI:https://doi.org/10.1088/0004-637X/771/2/109· OSTI ID:22140137

Jayawardhana, R. ^[1]; Brogi, M.; Snellen, I. A. G.; Hoekstra, H.; Bekkers, D. H.; Haffert, S. Y.; Van Houdt, J. J. ^[2]; De Kok, R. J. ^[3]

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1. Department of Astronomy and Astrophysics, University of Toronto, 50 St. George Street, Toronto, ON M5S 3H4 (Canada)
2. Leiden Observatory, Leiden University, Postbus 9513, 2300-RA, Leiden (Netherlands)
3. SRON Netherlands Institute for Space Research, Sorbonnelaan 2, 3584-CA, Utrecht (Netherlands)

We investigate the atmosphere of GJ1214b, a transiting super-Earth planet with a low mean density, by measuring its transit depth as a function of wavelength in the blue optical portion of the spectrum. It is thought that this planet is either a mini-Neptune, consisting of a rocky core with a thick, hydrogen-rich atmosphere, or a planet with a composition dominated by water. Most observations favor a water-dominated atmosphere with a small scale-height, however, some observations indicate that GJ1214b could have an extended atmosphere with a cloud layer muting the molecular features. In an atmosphere with a large scale-height, Rayleigh scattering at blue wavelengths is likely to cause a measurable increase in the apparent size of the planet toward the blue. We observed the transit of GJ1214b in the B band with the FOcal Reducing Spectrograph at the Very Large Telescope and in the g band with both ACAM on the William Herschel Telescope (WHT) and the Wide Field Camera at the Isaac Newton Telescope (INT). We find a planet-to-star radius ratio in the B band of 0.1162 {+-} 0.0017, and in the g band 0.1180 {+-} 0.0009 and 0.1174 {+-} 0.0017 for the WHT and INT observations, respectively. These optical data do not show significant deviations from previous measurements at longer wavelengths. In fact, a flat transmission spectrum across all wavelengths best describes the combined observations. When atmospheric models are considered, a small scale-height water-dominated model fits the data best.

• OSTI ID: 22140137
• Journal Information: Astrophysical Journal, Vol. 771, Issue 2; Other Information: Country of input: International Atomic Energy Agency (IAEA); ISSN 0004-637X
• Country of Publication: United States
• Language: English

Related Subjects

79 ASTROPHYSICS
COSMOLOGY AND ASTRONOMY
ATMOSPHERES
DENSITY
LAYERS
PLANETS
RAYLEIGH SCATTERING
SCALE HEIGHT
SPECTRA
STARS
TELESCOPES
TRANSMISSION
WATER
WAVELENGTHS