Detection of the secondary eclipse of Qatar-1b in the Ks band

Abstract

Qatar-1b is a close-orbiting hot Jupiter ($R_p\simeq 1.18$ $R_J$, $M_p\simeq 1.33$ $M_J$) around a metal-rich K-dwarf, with orbital separation and period of 0.023 AU and 1.42 days. We have observed the secondary eclipse of this exoplanet in the Ks band with the objective of deriving a brightness temperature for the planet and providing further constraints to the orbital configuration of the system. We obtained near-infrared photometric data from the ground by using the OMEGA2000 instrument at the 3.5 m telescope at Calar Alto (Spain) in staring mode, with the telescope defocused. We have used principal component analysis (PCA) to identify correlated systematic trends in the data. A Markov chain Monte Carlo analysis was performed to model the correlated systematics and fit for the secondary eclipse of Qatar-1b using a previously developed occultation model. We adopted the prayer bead method to assess the effect of red noise on the derived parameters. We measured a secondary eclipse depth of $0.196{\%}_{-0.051\%}^{+0.071\%}$, which indicates a brightness temperature in the Ks band for the planet of $1885_{-168}^{+212}$ K. We also measured a small deviation in the central phase of the secondary eclipse of $-0.0079_{-0.0043}^{+0.0162}$, which leads to a value for $e\cos \omega$ of $-0.0123_{-0.0067}^{+0.0252}$. However, this last result needs to be confirmed with more data.

6 pages, 6 figures, accepted for publication in A&A

References in corpus (5)

• Accurate Spitzer infrared radius measurement for the hot Neptune GJ 436b
• Thermal Emission from Transiting Very-Hot Jupiters: Prospects for Ground-based Detection at Optical Wavelengths
• High-precision multi-band time-series photometry of exoplanets Qatar-1b and TrES-5b
• Detection of the secondary eclipse of WASP-10b in the Ks-band
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Cited by in corpus (4)

• The TROY project: Searching for co-orbital bodies to known planets. I. Project goals and first results from archival radial velocity
• Smaller than expected bright-spot offsets in Spitzer phase curves of the hot Jupiter Qatar-1b
• The Renovated Thacher Observatory and First Science Results
• Colour-colour and colour-magnitude diagrams for Hot Jupiters