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arXiv · 2004.09109

WASP-4 transit timing variation from a comprehensive set of 129 transits

R. V. Baluev·E. N. Sokov·S. Hoyer·C. Huitson·José A. R. S. da Silva·P. Evans·I. A. Sokova·C. R. Knight·V. Sh. Shaidulin
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Abstract

We homogeneously reanalyse $124$ transit light curves for the WASP-4 b hot Jupiter. This set involved new observations secured in 2019 and nearly all observations mentioned in the literature, including high-accuracy GEMINI/GMOS transmission spectroscopy of 2011-2014 and TESS observations of 2018. The analysis confirmed a nonlinear TTV trend with $P/|\dot P|\sim (17-30)$ Myr (1-sigma range), implying only half of the initial decay rate estimation. The trend significance is at least $3.4$-sigma in the agressively conservative treatment. Possible radial acceleration due to unseen companions is not revealed in Doppler data covering seven years 2007-2014, and radial acceleration of $-15$ m s$^{-1}$yr$^{-1}$ reported in a recent preprint by another team is not confirmed. If present, it is a very nonlinear RV variation. Assuming that the entire TTV is tidal in nature, the tidal quality factor $Q_\star'\sim (4.5-8.5)\cdot 10^4$ does not reveal a convincing disagreement with available theory predictions.

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R. V. Baluev, E. N. Sokov, S. Hoyer, C. Huitson, José A. R. S. da Silva, P. Evans, I. A. Sokova, C. R. Knight, V. Sh. Shaidulin. 2020-04-20. WASP-4 transit timing variation from a comprehensive set of 129 transits. https://doi.org/10.1093/mnrasl%2Fslaa069

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