Tentative Evidence for Transit Timing Variations of WASP-161b by Fan Yang et al. on Monday 28 November

We report on the detection of transit timing variations (TTV) of WASP-161b by

using the combination of TESS data and archival data. The midpoint of the

transits in TESS data are offset by $\sim$67 minutes in Jan. 2019, and

$\sim$203 minutes in Jan. 2021, based on the ephemeris published in previous

work. We are able to reproduce the transit timings from the archival light

curve (SSO-Europa; Jan. 2018) and find SSO-Europa timing is consistent with the

published ephemeris under a constant period assumption. Conversely, we find

that the SSO-Europa transit midpoint indicates a 6.62-minute variation at 4.40

$\sigma$ compared to the prediction obtained from TESS timings, and a constant

orbit period assumption. The TTVs could be modeled with a quadratic function,

yielding a constant period change. The period derivative $\dot{P}$ is

-1.16$\times$10$^{-7}\pm$2.25$\times$10$^{-8}$ days per day (or $-3.65$

s/year), derived from SSO-Europa and TESS timing. Different scenarios,

including a decaying period and apsidal precession can potentially explain

these TTVs but they both introduce certain inconsistencies. We have obtained

CHEOPS observations for two transits in Jan. 2022 to distinguish between

different TTV scenarios. We expect the timing to vary by 5 minutes, compared to

the timing predicted from SSO-Europa and TESS with a constant period

assumption.

arXiv: http://arxiv.org/abs/http://arxiv.org/abs/2204.12306v2