Transit Timing Variation of XO-3b: Evidence for Tidal Evolution of Hot Jupiter with High Eccentricity
Abstract
Observed transit timing variation (TTV) potentially reveals the period decay caused by star-planet tidal interaction which can explain the orbital migration of hot Jupiters. We report the TTV of XO-3b, using TESS observed timings and archival timings. We generate a photometric pipeline to produce light curves from raw TESS images and find the difference between our pipeline and TESS PDC is negligible for timing analysis. TESS timing presents a shift of 17.6 minutes (80σ), earlier than the prediction from the previous ephemeris. The best linear fit for all timings available gives a Bayesian Information Criterion (BIC) value of 439. A quadratic function is a better model with a BIC of 56. The period derivative obtained from a quadratic function is -6.2 × 10-9 ± 2.9 × 10-10 per orbit, indicating an orbital decay timescale 1.4 Myr. We find that the orbital period decay can be well explained by tidal interaction. The "modified tidal quality factor" ${Q}_{p}^{{\prime} }$ would be 1.8 × 104 ± 8 × 102 if we assume the decay is due to the tide in the planet; whereas ${Q}_{* }^{{\prime} }$ would be 1.5 × 105 ± 6 × 103 if tidal dissipation is predominantly in the star. The precession model is another possible origin to explain the observed TTVs. We note that the follow-up observations of occultation timing and radial velocity monitoring are needed for fully discriminating the different models.
- Publication:
-
Publications of the Astronomical Society of the Pacific
- Pub Date:
- February 2022
- DOI:
- 10.1088/1538-3873/ac495a
- arXiv:
- arXiv:2111.06551
- Bibcode:
- 2022PASP..134b4401Y
- Keywords:
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- Exoplanet systems;
- Transit photometry;
- Transit timing variation method;
- Transit duration variation method;
- Tidal interaction;
- Exoplanet migration;
- Astrophysics - Earth and Planetary Astrophysics
- E-Print:
- 7 pages, 4 figures, Accepted