The impact of photospheric brightness field on exoplanetary transit timings and the TTV excess of HD 189733 b
| Autor: | Roman V. Baluev |
|---|---|
| Rok vydání: | 2021 |
| Předmět: |
Physics
Earth and Planetary Astrophysics (astro-ph.EP) Brightness Field (physics) Star (game theory) FOS: Physical sciences Astronomy and Astrophysics Radius Astrophysics Planetary system Exoplanet Astrophysics - Solar and Stellar Astrophysics Space and Planetary Science Astrophysics::Solar and Stellar Astrophysics Transit (astronomy) Surface brightness Astrophysics::Earth and Planetary Astrophysics Astrophysics - Instrumentation and Methods for Astrophysics Instrumentation and Methods for Astrophysics (astro-ph.IM) Solar and Stellar Astrophysics (astro-ph.SR) Astrophysics - Earth and Planetary Astrophysics |
| DOI: | 10.48550/arxiv.2110.07901 |
| Popis: | 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 ($\sim 10$ s) of the observed ($\sim 70$ 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 $\sim 0.01$ on the combination $\varepsilon_{\rm cell} r_{\rm cell}$, where $\varepsilon_{\rm cell}$ is the relative magnitude of brightness variations, and $r_{\rm cell}$ is the geometric cellularity scale (relative to star radius). Comment: 15 pages, 10 figures, 3 tables, accepted for publication in MNRAS |
| Databáze: | OpenAIRE |
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