Pre-discovery transits of the exoplanets WASP-18 b and WASP-33 b from Hipparcos

Abstract

We recover transits of WASP-18 b and WASP-33 b from Hipparcos (1989-1993) photometry. Marginal detections of HAT-P-56 b and HAT-P-2 b may be also present in the data. New ephemerides are fitted to WASP-18 b and WASP-33 b. A tentative (~1.3 sigma) orbital decay is measured for WASP-18 b, but the implied tidal quality factor (Q' ~ 5 x 10^5) is small and survival time (<10^6 years) is too short to be likely. No orbital decay is measured for WASP-33 b, and a limit of Q' > 2 x 10^5 is placed. For both planets, the uncertainties in published ephemerides appear underestimated: the uncertainty in the period derivative of WASP-18 b would be greatly reduced if its current ephemeris could be better determined.

4 pages, 3 figures, Accepted MNRAS Letters

References in corpus (9)

• Gaia Data Release 1. Summary of the astrometric, photometric, and survey properties
• Homogeneous studies of transiting extrasolar planets. I. Light curve analyses
• On the tidal evolution of Hot Jupiters on inclined orbits
• The Exoplanet Orbit Database II: Updates to exoplanets.org
• Foretellings of Ragnarök: World-engulfing Asymptotic Giants and the Inheritance of White Dwarfs
• Hierarchical Bayesian calibration of tidal orbit decay rates among hot Jupiters
• Searching For Rapid Orbital Decay of WASP-18b
• Lack of Transit Timing Variations of OGLE-TR-111b: A re-analysis with six new epochs
• Classical and relativistic node precessional effects in WASP-33b and perspectives for detecting them

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• Measuring the orbit shrinkage rate of hot Jupiters due to tides
• Refined Ephemeris for Four Hot Jupiters using Ground-Based and TESS Observations