SIMBAD references

2017AJ....154...95H - Astron. J., 154, 95-95 (2017/September-0)

Gemini/GMOS transmission spectral survey: complete optical transmission spectrum of the hot Jupiter WASP-4b.


Abstract (from CDS):

We present the complete optical transmission spectrum of the hot Jupiter WASP-4b from 440 to 940 nm at R ∼ 400-1500 obtained with the Gemini Multi-Object Spectrometers (GMOS); this is the first result from a comparative exoplanetology survey program of close-in gas giants conducted with GMOS. WASP-4b has an equilibrium temperature of 1700 K and is favorable to study in transmission due to its large scale height (370 km). We derive the transmission spectrum of WASP-4b using four transits observed with the MOS technique. We demonstrate repeatable results across multiple epochs with GMOS, and derive a combined transmission spectrum at a precision about twice above photon noise, which is roughly equal to one atmospheric scale height. The transmission spectrum is well fitted with a uniform opacity as a function of wavelength. The uniform opacity and absence of a Rayleigh slope from molecular hydrogen suggest that the atmosphere is dominated by clouds with condensate grain sizes of ∼1 µm. This result is consistent with previous observations of hot Jupiters since clouds have been seen in planets with similar equilibrium temperatures to WASP-4b. We describe a custom pipeline that we have written to reduce GMOS time-series data of exoplanet transits, and present a thorough analysis of the dominant noise sources in GMOS, which primarily consist of wavelength- and time-dependent displacements of the spectra on the detector, mainly due to a lack of atmospheric dispersion correction.

Abstract Copyright: © 2017. The American Astronomical Society. All rights reserved.

Journal keyword(s): planets and satellites: atmospheres - planets and satellites: individual WASP-4b - techniques: spectroscopic - techniques: spectroscopic

Simbad objects: 7

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