The impact of photospheric brightness field on exoplanetary transit timings and the TTV excess of HD 189733 b

Research output: Contribution to journalArticlepeer-review

Abstract

We consider the issue of excessive TTV noise observed for the exoplanet HD 189733 b. Trying to explain it through the host star photospheric activity, we model the stellar surface brightness as a random field, then characterize statistical properties of the resulting transit signal perturbation and compute individual corrections to transit timings uncertainties. We find that possible effect of the photospheric brightness field can explain only a minor portion (∼10 s) of the observed (∼70 s) TTV excess of HD 189733, suggesting that the rest should be attributed to other sources. Regarding the photospheric pattern, we place an upper limit of ∼0.01 on the combination ϵcellrcell, where ϵcell is the relative magnitude of brightness variations, and rcell is the geometric cellularity scale (relative to star radius).
Original languageEnglish
Pages (from-to)1048-1061
Number of pages14
JournalMonthly Notices of the Royal Astronomical Society
Volume509
Issue number1
Early online date23 Oct 2021
DOIs
StatePublished - Jan 2022

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