2019/07/31 by John Southworth, J. Southworth, M. Dominik +36 · 1 citation
Physics and Astronomy · #Astro and Planetary Science #Astrobiology #Astronomy #Astrophysics #Astrophysics and Star Formation Studies #Exoplanet #Physics #Planet #Planetary system #Stellar, planetary, and galactic studies #Transit (satellite) #astro-ph.EP
paper · pdf · doi:10.1093/mnras/stz2602
Accepted for publication to MNRAS Main Journal. 7 pages, 2 colour figures, 1 table. Version 2 is the revised version after the refereeing process, which includes changes to some of the conclusions of the paper
arxiv created 2019/09/12 · openalex publication_date 2019/09/18 · arxiv updated 2019/09/25 · openalex created_date 2025/10/10 · openalex updated_date 2026/08/05
ABSTRACT Transits in the planetary system WASP-4 were recently found to occur 80 s earlier than expected in observations from the TESS satellite. We present 22 new times of mid-transit that confirm the existence of transit timing variations, and are well fitted by a quadratic ephemeris with period decay dP/dt = −9.2 ± 1.1 ms yr−1. We rule out instrumental issues, stellar activity, and the Applegate mechanism as possible causes. The light-time effect is also not favoured due to the non-detection of changes in the systemic velocity. Orbital decay and apsidal precession are plausible but unproven. WASP-4 b is only the third hot Jupiter known to show transit timing variations to high confidence. We discuss a variety of observations of this and other planetary systems that would be useful in improving our understanding of WASP-4 in particular and orbital decay in general.