New Mass and Radius Constraints on the LHS 1140 Planets: LHS 1140 b Is either a Temperate Mini-Neptune or a Water World

Charles Cadieux; Mykhaylo Plotnykov; René Doyon; Diana Valencia; Farbod Jahandar; Lisa Dang; Martin Turbet; Thomas J. Fauchez; Ryan Cloutier; Collin Cherubim; Étienne Artigau; Neil J. Cook; Billy Edwards; Tim Hallatt; Benjamin Charnay; François Bouchy; Romain Allart; Lucile Mignon; Frédérique Baron; Susana C.C. Barros; Björn Benneke; B. L. Canto Martins; Nicolas B. Cowan; J. R. De Medeiros; Xavier Delfosse; Elisa Delgado-Mena; Xavier Dumusque; David Ehrenreich; Yolanda G.C. Frensch; J. I. González Hernández; Nathan C. Hara; David Lafrenière; Gaspare Lo Curto; Lison Malo; Claudio Melo; Dany Mounzer; Vera Maria Passeger; Francesco Pepe; Anne Sophie Poulin-Girard; Nuno C. Santos; Danuta Sosnowska; Alejandro Suárez Mascareño; Simon Thibault; Valentina Vaulato; Gregg A. Wade; François Wildi

doi:10.3847/2041-8213/ad1691

New Mass and Radius Constraints on the LHS 1140 Planets: LHS 1140 b Is either a Temperate Mini-Neptune or a Water World

Charles Cadieux
, Mykhaylo Plotnykov
, René Doyon
, Diana Valencia
, Farbod Jahandar
, Lisa Dang
, Martin Turbet
, Thomas J. Fauchez
, Ryan Cloutier
, Collin Cherubim
, Étienne Artigau
, Neil J. Cook
, Billy Edwards
, Tim Hallatt
, Benjamin Charnay
, François Bouchy
, Romain Allart
, Lucile Mignon
, Frédérique Baron
, Susana C.C. Barros

Björn Benneke, B. L. Canto Martins, Nicolas B. Cowan, J. R. De Medeiros, Xavier Delfosse, Elisa Delgado-Mena, Xavier Dumusque, David Ehrenreich, Yolanda G.C. Frensch, J. I. González Hernández, Nathan C. Hara, David Lafrenière, Gaspare Lo Curto, Lison Malo, Claudio Melo, Dany Mounzer, Vera Maria Passeger, Francesco Pepe, Anne Sophie Poulin-Girard, Nuno C. Santos, Danuta Sosnowska, Alejandro Suárez Mascareño, Simon Thibault, Valentina Vaulato, Gregg A. Wade, François Wildi

Universite de Montreal
University of Toronto
Laboratoire d'Astrophysique de Bordeaux
NASA Goddard Space Flight Center
American University
McMaster University, Faculty of Science
Harvard University
Center for Astrophysics | Harvard & Smithsonian
SRON - Netherlands Institute for Space Research
University College London
McGill University
Sorbonne Univ.
University of Geneva
Ipatimup Diagnósticos
The Federal University of Rio Grande do Norte
Université Grenoble Alpes
Instituto de Astrofisica de Canarias
Research Unit; CIBERNED and Universidad de La Laguna
European Southern Observatory
Universität Hamburg

Research output: Contribution to journal › Article › peer-review

Abstract

The two-planet transiting system LHS 1140 has been extensively observed since its discovery in 2017, notably with Spitzer, HST, TESS, and ESPRESSO, placing strong constraints on the parameters of the M4.5 host star and its small temperate exoplanets, LHS 1140 b and c. Here, we reanalyze the ESPRESSO observations of LHS 1140 with the novel line-by-line framework designed to fully exploit the radial velocity content of a stellar spectrum while being resilient to outlier measurements. The improved radial velocities, combined with updated stellar parameters, consolidate our knowledge of the mass of LHS 1140 b (5.60 ± 0.19 M _⊕) and LHS 1140 c (1.91 ± 0.06 M _⊕) with an unprecedented precision of 3%. Transits from Spitzer, HST, and TESS are jointly analyzed for the first time, allowing us to refine the planetary radii of b (1.730 ± 0.025 R _⊕) and c (1.272 ± 0.026 R _⊕). Stellar abundance measurements of refractory elements (Fe, Mg, and Si) obtained with NIRPS are used to constrain the internal structure of LHS 1140 b. This planet is unlikely to be a rocky super-Earth, as previously reported, but rather a mini-Neptune with a ∼0.1% H/He envelope by mass or a water world with a water-mass fraction between 9% and 19%, depending on the atmospheric composition and relative abundance of Fe and Mg. While the mini-Neptune case would not be habitable, a water-abundant LHS 1140 b potentially has habitable surface conditions according to 3D global climate models, suggesting liquid water at the substellar point for atmospheres with relatively low CO₂ concentration, from Earth-like to a few bars.

Original language	English
Article number	L3
Journal	Astrophysical Journal Letters
Volume	960
Issue number	1
DOIs	https://doi.org/10.3847/2041-8213/ad1691
Publication status	Published - 1 Jan 2024

UN SDGs

This output contributes to the following UN Sustainable Development Goals (SDGs)

SDG 13 Climate Action

Access to Document

10.3847/2041-8213/ad1691

Cite this

Cadieux, C., Plotnykov, M., Doyon, R., Valencia, D., Jahandar, F., Dang, L., Turbet, M., Fauchez, T. J., Cloutier, R., Cherubim, C., Artigau, É., Cook, N. J., Edwards, B., Hallatt, T., Charnay, B., Bouchy, F., Allart, R., Mignon, L., Baron, F., ... Wildi, F. (2024). New Mass and Radius Constraints on the LHS 1140 Planets: LHS 1140 b Is either a Temperate Mini-Neptune or a Water World. Astrophysical Journal Letters, 960(1), Article L3. https://doi.org/10.3847/2041-8213/ad1691

@article{710ae5f97439434cbc8a7cfe61b0cbb0,

title = "New Mass and Radius Constraints on the LHS 1140 Planets: LHS 1140 b Is either a Temperate Mini-Neptune or a Water World",

abstract = "The two-planet transiting system LHS 1140 has been extensively observed since its discovery in 2017, notably with Spitzer, HST, TESS, and ESPRESSO, placing strong constraints on the parameters of the M4.5 host star and its small temperate exoplanets, LHS 1140 b and c. Here, we reanalyze the ESPRESSO observations of LHS 1140 with the novel line-by-line framework designed to fully exploit the radial velocity content of a stellar spectrum while being resilient to outlier measurements. The improved radial velocities, combined with updated stellar parameters, consolidate our knowledge of the mass of LHS 1140 b (5.60 ± 0.19 M ⊕) and LHS 1140 c (1.91 ± 0.06 M ⊕) with an unprecedented precision of 3\%. Transits from Spitzer, HST, and TESS are jointly analyzed for the first time, allowing us to refine the planetary radii of b (1.730 ± 0.025 R ⊕) and c (1.272 ± 0.026 R ⊕). Stellar abundance measurements of refractory elements (Fe, Mg, and Si) obtained with NIRPS are used to constrain the internal structure of LHS 1140 b. This planet is unlikely to be a rocky super-Earth, as previously reported, but rather a mini-Neptune with a ∼0.1\% H/He envelope by mass or a water world with a water-mass fraction between 9\% and 19\%, depending on the atmospheric composition and relative abundance of Fe and Mg. While the mini-Neptune case would not be habitable, a water-abundant LHS 1140 b potentially has habitable surface conditions according to 3D global climate models, suggesting liquid water at the substellar point for atmospheres with relatively low CO2 concentration, from Earth-like to a few bars.",

author = "Charles Cadieux and Mykhaylo Plotnykov and Ren{\'e} Doyon and Diana Valencia and Farbod Jahandar and Lisa Dang and Martin Turbet and Fauchez, \{Thomas J.\} and Ryan Cloutier and Collin Cherubim and {\'E}tienne Artigau and Cook, \{Neil J.\} and Billy Edwards and Tim Hallatt and Benjamin Charnay and Fran{\c c}ois Bouchy and Romain Allart and Lucile Mignon and Fr{\'e}d{\'e}rique Baron and Barros, \{Susana C.C.\} and Bj{\"o}rn Benneke and \{Canto Martins\}, \{B. L.\} and Cowan, \{Nicolas B.\} and \{De Medeiros\}, \{J. R.\} and Xavier Delfosse and Elisa Delgado-Mena and Xavier Dumusque and David Ehrenreich and Frensch, \{Yolanda G.C.\} and \{Gonz{\'a}lez Hern{\'a}ndez\}, \{J. I.\} and Hara, \{Nathan C.\} and David Lafreni{\`e}re and Curto, \{Gaspare Lo\} and Lison Malo and Claudio Melo and Dany Mounzer and Passeger, \{Vera Maria\} and Francesco Pepe and Poulin-Girard, \{Anne Sophie\} and Santos, \{Nuno C.\} and Danuta Sosnowska and \{Su{\'a}rez Mascare{\~n}o\}, Alejandro and Simon Thibault and Valentina Vaulato and Wade, \{Gregg A.\} and Fran{\c c}ois Wildi",

note = "Publisher Copyright: {\textcopyright} 2024. The Author(s). Published by the American Astronomical Society.",

year = "2024",

month = jan,

day = "1",

doi = "10.3847/2041-8213/ad1691",

language = "English",

volume = "960",

journal = "Astrophysical Journal Letters",

issn = "2041-8205",

number = "1",

}

Cadieux, C, Plotnykov, M, Doyon, R, Valencia, D, Jahandar, F, Dang, L, Turbet, M, Fauchez, TJ, Cloutier, R, Cherubim, C, Artigau, É, Cook, NJ, Edwards, B, Hallatt, T, Charnay, B, Bouchy, F, Allart, R, Mignon, L, Baron, F, Barros, SCC, Benneke, B, Canto Martins, BL, Cowan, NB, De Medeiros, JR, Delfosse, X, Delgado-Mena, E, Dumusque, X, Ehrenreich, D, Frensch, YGC, González Hernández, JI, Hara, NC, Lafrenière, D, Curto, GL, Malo, L, Melo, C, Mounzer, D, Passeger, VM, Pepe, F, Poulin-Girard, AS, Santos, NC, Sosnowska, D, Suárez Mascareño, A, Thibault, S, Vaulato, V, Wade, GA & Wildi, F 2024, 'New Mass and Radius Constraints on the LHS 1140 Planets: LHS 1140 b Is either a Temperate Mini-Neptune or a Water World', Astrophysical Journal Letters, vol. 960, no. 1, L3. https://doi.org/10.3847/2041-8213/ad1691

TY - JOUR

T1 - New Mass and Radius Constraints on the LHS 1140 Planets

T2 - LHS 1140 b Is either a Temperate Mini-Neptune or a Water World

AU - Cadieux, Charles

AU - Plotnykov, Mykhaylo

AU - Doyon, René

AU - Valencia, Diana

AU - Jahandar, Farbod

AU - Dang, Lisa

AU - Turbet, Martin

AU - Fauchez, Thomas J.

AU - Cloutier, Ryan

AU - Cherubim, Collin

AU - Artigau, Étienne

AU - Cook, Neil J.

AU - Edwards, Billy

AU - Hallatt, Tim

AU - Charnay, Benjamin

AU - Bouchy, François

AU - Allart, Romain

AU - Mignon, Lucile

AU - Baron, Frédérique

AU - Barros, Susana C.C.

AU - Benneke, Björn

AU - Canto Martins, B. L.

AU - Cowan, Nicolas B.

AU - De Medeiros, J. R.

AU - Delfosse, Xavier

AU - Delgado-Mena, Elisa

AU - Dumusque, Xavier

AU - Ehrenreich, David

AU - Frensch, Yolanda G.C.

AU - González Hernández, J. I.

AU - Hara, Nathan C.

AU - Lafrenière, David

AU - Curto, Gaspare Lo

AU - Malo, Lison

AU - Melo, Claudio

AU - Mounzer, Dany

AU - Passeger, Vera Maria

AU - Pepe, Francesco

AU - Poulin-Girard, Anne Sophie

AU - Santos, Nuno C.

AU - Sosnowska, Danuta

AU - Suárez Mascareño, Alejandro

AU - Thibault, Simon

AU - Vaulato, Valentina

AU - Wade, Gregg A.

AU - Wildi, François

PY - 2024/1/1

Y1 - 2024/1/1

N2 - The two-planet transiting system LHS 1140 has been extensively observed since its discovery in 2017, notably with Spitzer, HST, TESS, and ESPRESSO, placing strong constraints on the parameters of the M4.5 host star and its small temperate exoplanets, LHS 1140 b and c. Here, we reanalyze the ESPRESSO observations of LHS 1140 with the novel line-by-line framework designed to fully exploit the radial velocity content of a stellar spectrum while being resilient to outlier measurements. The improved radial velocities, combined with updated stellar parameters, consolidate our knowledge of the mass of LHS 1140 b (5.60 ± 0.19 M ⊕) and LHS 1140 c (1.91 ± 0.06 M ⊕) with an unprecedented precision of 3%. Transits from Spitzer, HST, and TESS are jointly analyzed for the first time, allowing us to refine the planetary radii of b (1.730 ± 0.025 R ⊕) and c (1.272 ± 0.026 R ⊕). Stellar abundance measurements of refractory elements (Fe, Mg, and Si) obtained with NIRPS are used to constrain the internal structure of LHS 1140 b. This planet is unlikely to be a rocky super-Earth, as previously reported, but rather a mini-Neptune with a ∼0.1% H/He envelope by mass or a water world with a water-mass fraction between 9% and 19%, depending on the atmospheric composition and relative abundance of Fe and Mg. While the mini-Neptune case would not be habitable, a water-abundant LHS 1140 b potentially has habitable surface conditions according to 3D global climate models, suggesting liquid water at the substellar point for atmospheres with relatively low CO2 concentration, from Earth-like to a few bars.

AB - The two-planet transiting system LHS 1140 has been extensively observed since its discovery in 2017, notably with Spitzer, HST, TESS, and ESPRESSO, placing strong constraints on the parameters of the M4.5 host star and its small temperate exoplanets, LHS 1140 b and c. Here, we reanalyze the ESPRESSO observations of LHS 1140 with the novel line-by-line framework designed to fully exploit the radial velocity content of a stellar spectrum while being resilient to outlier measurements. The improved radial velocities, combined with updated stellar parameters, consolidate our knowledge of the mass of LHS 1140 b (5.60 ± 0.19 M ⊕) and LHS 1140 c (1.91 ± 0.06 M ⊕) with an unprecedented precision of 3%. Transits from Spitzer, HST, and TESS are jointly analyzed for the first time, allowing us to refine the planetary radii of b (1.730 ± 0.025 R ⊕) and c (1.272 ± 0.026 R ⊕). Stellar abundance measurements of refractory elements (Fe, Mg, and Si) obtained with NIRPS are used to constrain the internal structure of LHS 1140 b. This planet is unlikely to be a rocky super-Earth, as previously reported, but rather a mini-Neptune with a ∼0.1% H/He envelope by mass or a water world with a water-mass fraction between 9% and 19%, depending on the atmospheric composition and relative abundance of Fe and Mg. While the mini-Neptune case would not be habitable, a water-abundant LHS 1140 b potentially has habitable surface conditions according to 3D global climate models, suggesting liquid water at the substellar point for atmospheres with relatively low CO2 concentration, from Earth-like to a few bars.

U2 - 10.3847/2041-8213/ad1691

DO - 10.3847/2041-8213/ad1691

M3 - Article

AN - SCOPUS:85182372922

SN - 2041-8205

VL - 960

JO - Astrophysical Journal Letters

JF - Astrophysical Journal Letters

IS - 1

M1 - L3

ER -

New Mass and Radius Constraints on the LHS 1140 Planets: LHS 1140 b Is either a Temperate Mini-Neptune or a Water World

Abstract

UN SDGs

Access to Document

Fingerprint

Cite this