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arXiv · 2002.02197

A new orbital ephemeris for WASP-128b

Alexis M. S. Smith·Philipp Eigmüller·Mahmoudreza Oshagh·John Southworth
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Abstract

WASP-128 is a relatively bright (V= 12.37) G0-dwarf, known to host a transiting brown dwarf in a short-period orbit (Hodžić et al. 2018 arXiv:1807.07557 (H18)). Very few such objects are known, which makes WASP-128 a prime target for further observations to better understand giant planet / brown dwarf properties,including formation and migration histories. To facilitate the planning of future observations of WASP-128b, we improve the orbital ephemeris of the system, by using the seven transits of WASP-128 observed by TESS. We note that our orbital period differs significantly from that of H18: it is more than $14\,σ$ (using their uncertainty) larger. This results in our ephemeris predicting a mid-2020 transit to occur almost eight hours later than the H18 ephemeris. We find, however, no evidence for any period variation.

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Alexis M. S. Smith, Philipp Eigmüller, Mahmoudreza Oshagh, John Southworth. 2020-02-14. A new orbital ephemeris for WASP-128b. https://doi.org/10.3847/2515-5172%2Fab7343

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