Howarth, ID;
Morello, G;
(2017)
Rapid rotators revisited: absolute dimensions of KOI-13.
Monthly Notices of the Royal Astronomical Society
, 470
(1)
pp. 932-939.
10.1093/mnras/stx1260.
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Abstract
We analyse Kepler light-curves of the exoplanet Kepler Object of Interest no. 13b (KOI-13b) transiting its moderately rapidly rotating (gravity-darkened) parent star. A physical model, with minimal ad hoc free parameters, reproduces the time-averaged light-curve at the ∼10 parts per million level. We demonstrate that this Roche-model solution allows the absolute dimensions of the system to be determined from the star's projected equatorial rotation speed, ve sin i*, without any additional assumptions; we find a planetary radius RP = (1.33 ± 0.05) R♃, stellar polar radius Rp★ = (1.55 ± 0.06) R⊙, combined mass M* + MP( ≃ M*) = (1.47 ± 0.17) M⊙ and distance d ≃ (370 ± 25) pc, where the errors are dominated by uncertainties in relative flux contribution of the visual-binary companion KOI-13B. The implied stellar rotation period is within ∼5 per cent of the non-orbital, 25.43-hr signal found in the Kepler photometry. We show that the model accurately reproduces independent tomographic observations, and yields an offset between orbital and stellar-rotation angular-momentum vectors of 60 ∘. .∘ 25 ± 0 ∘. .∘ 05.
| Type: | Article |
|---|---|
| Title: | Rapid rotators revisited: absolute dimensions of KOI-13 |
| Open access status: | An open access version is available from UCL Discovery |
| DOI: | 10.1093/mnras/stx1260 |
| Publisher version: | https://doi.org/10.1093/mnras/stx1260 |
| Language: | English |
| Additional information: | This is the published version of record. For information on re-use, please refer to the publisher’s terms and conditions. |
| Keywords: | stars: fundamental parameters; stars: individual: KOI-13; stars: rotation |
| UCL classification: | UCL UCL > Provost and Vice Provost Offices > UCL BEAMS UCL > Provost and Vice Provost Offices > UCL BEAMS > Faculty of Maths and Physical Sciences UCL > Provost and Vice Provost Offices > UCL BEAMS > Faculty of Maths and Physical Sciences > Dept of Physics and Astronomy |
| URI: | https://discovery-pp.ucl.ac.uk/id/eprint/10025239 |
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