_version_ 1866909430504751104
author Ducrot, Elsa
Lagage, Pierre-Olivier
Min, Michiel
Gillon, Michael
Bell, Taylor J.
Tremblin, Pascal
Greene, Thomas
Dyrek, Achrene
Bouwman, Jeroen
Waters, Rens
Gudel, Manuel
Henning, Thomas
Vandenbussche, Bart
Absil, Olivier
Barrado, David
Boccaletti, Anthony
Coulais, Alain
Decin, Leen
Edwards, Billy
Gastaud, Rene
Glasse, Alistair
Kendrew, Sarah
Olofsson, Goran
Patapis, Polychronis
Pye, John
Rouan, Daniel
Whiteford, Niall
Argyriou, Ioannis
Cossou, Christophe
Glauser, Adrian M.
Krause, Oliver
Lahuis, Fred
Royer, Pierre
Scheithauer, Silvia
Colina, Luis
van Dishoeck, Ewine F.
Ostlin, Goran
Ray, Tom P.
Wright, Gillian
author_facet Ducrot, Elsa
Lagage, Pierre-Olivier
Min, Michiel
Gillon, Michael
Bell, Taylor J.
Tremblin, Pascal
Greene, Thomas
Dyrek, Achrene
Bouwman, Jeroen
Waters, Rens
Gudel, Manuel
Henning, Thomas
Vandenbussche, Bart
Absil, Olivier
Barrado, David
Boccaletti, Anthony
Coulais, Alain
Decin, Leen
Edwards, Billy
Gastaud, Rene
Glasse, Alistair
Kendrew, Sarah
Olofsson, Goran
Patapis, Polychronis
Pye, John
Rouan, Daniel
Whiteford, Niall
Argyriou, Ioannis
Cossou, Christophe
Glauser, Adrian M.
Krause, Oliver
Lahuis, Fred
Royer, Pierre
Scheithauer, Silvia
Colina, Luis
van Dishoeck, Ewine F.
Ostlin, Goran
Ray, Tom P.
Wright, Gillian
contents The first JWST/MIRI photometric observations of TRAPPIST-1 b allowed for the detection of the thermal emission of the planet at 15 $μm$, suggesting that the planet could be a bare rock with a zero albedo and no redistribution of heat. These observations at 15 $μm$ were acquired as part of GTO time that included a twin program at 12.8 $μm$ in order to have a measurement in and outside the CO$_2$ absorption band. Here we present five new occultations of TRAPPIST-1 b observed with MIRI in an additional photometric band at 12.8 $μm$. We perform a global fit of the 10 eclipses and derive a planet-to-star flux ratio and 1-$σ$ error of 452 $\pm$ 86 ppm and 775 $\pm$ 90 ppm at 12.8 $μm$ and 15 $μm$, respectively. We find that two main scenarios emerge. An airless planet model with an unweathered (fresh) ultramafic surface, that could be indicative of relatively recent geological processes fits well the data. Alternatively, a thick, pure-CO2 atmosphere with photochemical hazes that create a temperature inversion and result in the CO2 feature being seen in emission also works, although with some caveats. Our results highlight the challenges in accurately determining a planet's atmospheric or surface nature solely from broadband filter measurements of its emission, but also point towards two very interesting scenarios that will be further investigated with the forthcoming phase curve of TRAPPIST-1 b.
format Preprint
id arxiv_https___arxiv_org_abs_2412_11627
institution arXiv
publishDate 2024
record_format arxiv
spellingShingle Combined analysis of the 12.8 and 15 $μm$ JWST/MIRI eclipse observations of TRAPPIST-1 b
Ducrot, Elsa
Lagage, Pierre-Olivier
Min, Michiel
Gillon, Michael
Bell, Taylor J.
Tremblin, Pascal
Greene, Thomas
Dyrek, Achrene
Bouwman, Jeroen
Waters, Rens
Gudel, Manuel
Henning, Thomas
Vandenbussche, Bart
Absil, Olivier
Barrado, David
Boccaletti, Anthony
Coulais, Alain
Decin, Leen
Edwards, Billy
Gastaud, Rene
Glasse, Alistair
Kendrew, Sarah
Olofsson, Goran
Patapis, Polychronis
Pye, John
Rouan, Daniel
Whiteford, Niall
Argyriou, Ioannis
Cossou, Christophe
Glauser, Adrian M.
Krause, Oliver
Lahuis, Fred
Royer, Pierre
Scheithauer, Silvia
Colina, Luis
van Dishoeck, Ewine F.
Ostlin, Goran
Ray, Tom P.
Wright, Gillian
Earth and Planetary Astrophysics
The first JWST/MIRI photometric observations of TRAPPIST-1 b allowed for the detection of the thermal emission of the planet at 15 $μm$, suggesting that the planet could be a bare rock with a zero albedo and no redistribution of heat. These observations at 15 $μm$ were acquired as part of GTO time that included a twin program at 12.8 $μm$ in order to have a measurement in and outside the CO$_2$ absorption band. Here we present five new occultations of TRAPPIST-1 b observed with MIRI in an additional photometric band at 12.8 $μm$. We perform a global fit of the 10 eclipses and derive a planet-to-star flux ratio and 1-$σ$ error of 452 $\pm$ 86 ppm and 775 $\pm$ 90 ppm at 12.8 $μm$ and 15 $μm$, respectively. We find that two main scenarios emerge. An airless planet model with an unweathered (fresh) ultramafic surface, that could be indicative of relatively recent geological processes fits well the data. Alternatively, a thick, pure-CO2 atmosphere with photochemical hazes that create a temperature inversion and result in the CO2 feature being seen in emission also works, although with some caveats. Our results highlight the challenges in accurately determining a planet's atmospheric or surface nature solely from broadband filter measurements of its emission, but also point towards two very interesting scenarios that will be further investigated with the forthcoming phase curve of TRAPPIST-1 b.
title Combined analysis of the 12.8 and 15 $μm$ JWST/MIRI eclipse observations of TRAPPIST-1 b
topic Earth and Planetary Astrophysics
url https://arxiv.org/abs/2412.11627