A transit timing variation observed for the long-period extremely low-density exoplanet HIP 41378 f. Issue 1 (16th April 2021)

• Record Type: Journal Article
• Authors: Bryant, Edward M; Bayliss, Daniel; Santerne, Alexandre; Wheatley, Peter J; Nascimbeni, Valerio; Ducrot, Elsa; Burdanov, Artem; Acton, Jack S; Alves, Douglas R; Anderson, David R; Armstrong, David J; Awiphan, Supachai; Cooke, Benjamin F; Burleigh, Matthew R; Casewell, Sarah L; Delrez, Laetitia; Demory, Brice-Olivier; Eigmüller, Philipp; Fukui, Akihiko; Gan, Tianjun; Gill, Samuel; Gillon, Michael; Goad, Michael R; Tan, Thiam-Guan; Günther, Maximilian N; Hardee, Bronwen; Henderson, Beth A; Jehin, Emmanuel; Jenkins, James S; Kosiarek, Molly; Lendl, Monika; Moyano, Maximiliano; Murray, Catriona A; Narita, Norio; Niraula, Prajwal; Odden, Caroline E; Palle, Enric; Parviainen, Hannu; Pedersen, Peter P; Pozuelos, Francisco J; V Rackham, Benjamin; Sebastian, Daniel; Stockdale, Chris; Tilbrook, Rosanna H; Thompson, Samantha J; Triaud, Amaury H M J; Udry, Stéphane; Vines, Jose I; West, Richard G; de Wit, Julien;
• Is Part Of: Monthly notices of the Royal Astronomical Society. Volume 504:Issue 1(2021)
• Page Start: L45
• Page End: L50
• Publication Date: 2021-04-16
• Subjects: techniques: photometric -- planets and satellites: detection -- planets and satellites: individual: HIP 41378 f -- stars: individual: HIP 41378; Astronomy -- Research -- Periodicals; Periodicals; 520.5
• DOI: 10.1093/mnrasl/slab037
• Languages: English
• ISSNs: 1745-3933

Abstract

ABSTRACT: HIP 41378 f is a temperate 9.2 ± 0.1 R ⊕ planet with period of 542.08 d and an extremely low density of 0.09 ± 0.02 g cm −3 . It transits the bright star HIP 41378 ( V = 8.93), making it an exciting target for atmospheric characterization including transmission spectroscopy. HIP 41378 was monitored photometrically between the dates of 2019 November 19 and 28. We detected a transit of HIP 41378 f with NGTS, just the third transit ever detected for this planet, which confirms the orbital period. This is also the first ground-based detection of a transit of HIP 41378 f. Additional ground-based photometry was also obtained and used to constrain the time of the transit. The transit was measured to occur 1.50 h earlier than predicted. We use an analytic transit timing variation (TTV) model to show the observed TTV can be explained by interactions between HIP 41378 e and HIP 41378 f. Using our TTV model, we predict the epochs of future transits of HIP 41378 f, with derived transit centres of T C, 4 = $2459\, 355.087^{+0.031}_{-0.022}$ (2021 May) and T C, 5 = $2459\, 897.078^{+0.114}_{-0.060}$ (2022 November).