Transit timing variations in the WASP-4 planetary system

Southworth, John; Dominik, M; Jørgensen, U G; Andersen, M I; Bozza, V; Burgdorf, M J; D’Ago, G; Dib, S; Figuera Jaimes, R; Fujii, Y I; Gill, S; Haikala, L K; Hinse, T C; Hundertmark, M; Khalouei, E; Korhonen, H; Longa-Peña, P; Mancini, L; Peixinho, N; Rabus, M; Rahvar, S; Sajadian, S; Skottfelt, J; Snodgrass, C; Spyratos, P; Tregloan-Reed, J; Unda-Sanzana, E; von Essen, C

doi:10.1093/mnras/stz2602

Transit timing variations in the WASP-4 planetary system

Southworth, John; Dominik, M; Jørgensen, U G; Andersen, M I; Bozza, V; Burgdorf, M J; D’Ago, G; Dib, S; Figuera Jaimes, R; Fujii, Y I; Gill, S; Haikala, L K; Hinse, T C; Hundertmark, M; Khalouei, E; Korhonen, H; Longa-Peña, P; Mancini, L; Peixinho, N; Rabus, M; Rahvar, S; Sajadian, S; Skottfelt, J; Snodgrass, C; Spyratos, P; Tregloan-Reed, J; Unda-Sanzana, E; von Essen, C

Authors

Dr John Taylor j.k.taylor@keele.ac.uk

M Dominik

U G Jørgensen

M I Andersen

V Bozza

M J Burgdorf

G D’Ago

S Dib

R Figuera Jaimes

Y I Fujii

S Gill

L K Haikala

T C Hinse

M Hundertmark

E Khalouei

H Korhonen

P Longa-Peña

L Mancini

N Peixinho

M Rabus

S Rahvar

S Sajadian

J Skottfelt

C Snodgrass

P Spyratos

J Tregloan-Reed

E Unda-Sanzana

C von Essen

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.

Journal Article Type	Article
Acceptance Date	Sep 11, 2019
Online Publication Date	Sep 19, 2019
Publication Date	2019-12
Publicly Available Date	May 26, 2023
Journal	Monthly Notices of the Royal Astronomical Society
Print ISSN	0035-8711
Publisher	Oxford University Press
Peer Reviewed	Peer Reviewed
Volume	490
Issue	3
Pages	4230 - 4236
DOI	https://doi.org/10.1093/mnras/stz2602
Keywords	stars, activity, fundamental parameters, individual, WASP-4
Publisher URL	https://doi.org/10.1093/mnras/stz2602