Early 2017 observations of TRAPPIST-1 with Spitzer

Delrez, L; Gillon, M; Triaud, A H M J; Demory, Brice-Olivier; de Wit, J; Ingalls, J G; Agol, E; Bolmont, E; Burdanov, A; Burgasser, A J; Carey, S J; Jehin, E; Leconte, J; Lederer, S; Queloz, D; Selsis, F; Van Grootel, V (2018). Early 2017 observations of TRAPPIST-1 with Spitzer. Monthly notices of the Royal Astronomical Society, 475(3), pp. 3577-3597. Oxford University Press 10.1093/mnras/sty051

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The recently detected TRAPPIST-1 planetary system, with its seven planets transiting a nearby ultracool dwarf star, offers the first opportunity to perform comparative exoplanetology of temperate Earth-sized worlds. To further advance our understanding of these planets’ compositions, energy budgets, and dynamics, we are carrying out an intensive photometric monitoring campaign of their transits with the Spitzer Space Telescope. In this context, we present 60 new transits of the TRAPPIST-1 planets observed with Spitzer/Infrared Array Camera (IRAC) in 2017 February and March. We combine these observations with previously published Spitzer transit photometry and perform a global analysis of the resulting extensive data set. This analysis refines the transit parameters and provides revised values for the planets’ physical parameters, notably their radii, using updated properties for the star. As part of our study, we also measure precise transit timings that will be used in a companion paper to refine the planets’ masses and compositions using the transit timing variations method. TRAPPIST-1 shows a very low level of low-frequency variability in the IRAC 4.5-μm band, with a photometric RMS of only 0.11 per cent at a 123-s cadence. We do not detect any evidence of a (quasi-)periodic signal related to stellar rotation. We also analyse the transit light curves individually, to search for possible variations in the transit parameters of each planet due to stellar variability, and find that the Spitzer transits of the planets are mostly immune to the effects of stellar variations. These results are encouraging for forthcoming transmission spectroscopy observations of the TRAPPIST-1 planets with the James Webb Space Telescope.

Item Type:

Journal Article (Original Article)

Division/Institute:

08 Faculty of Science > Physics Institute > Space Research and Planetary Sciences
08 Faculty of Science > Physics Institute
10 Strategic Research Centers > Center for Space and Habitability (CSH)
08 Faculty of Science > Physics Institute > NCCR PlanetS

UniBE Contributor:

Demory, Brice-Olivier

Subjects:

500 Science > 520 Astronomy
500 Science > 530 Physics

ISSN:

0035-8711

Publisher:

Oxford University Press

Language:

English

Submitter:

Danielle Zemp

Date Deposited:

29 May 2019 17:22

Last Modified:

29 May 2019 17:22

Publisher DOI:

10.1093/mnras/sty051

BORIS DOI:

10.7892/boris.126816

URI:

https://boris.unibe.ch/id/eprint/126816

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