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New Mass and Radius Constraints on the LHS 1140 Planets -- LHS 1140 b is Either a Temperate Mini-Neptune or a Water World

dc.contributor.authorCADIEUX, Charles
dc.contributor.authorPLOTNYKOV, Mykhaylo
dc.contributor.authorDOYON, René
dc.contributor.authorVALENCIA, Diana
dc.contributor.authorJAHANDAR, Farbod
dc.contributor.authorDANG, Lisa
hal.structure.identifierLaboratoire de Météorologie Dynamique (UMR 8539) [LMD]
hal.structure.identifierInstitut Pierre-Simon-Laplace [IPSL (FR_636)]
hal.structure.identifierLaboratoire d'Astrophysique de Bordeaux [Pessac] [LAB]
dc.contributor.authorTURBET, Martin
dc.contributor.authorFAUCHEZ, Thomas
dc.contributor.authorCLOUTIER, Ryan
dc.contributor.authorCHERUBIM, Collin
dc.contributor.authorARTIGAU, Étienne
dc.contributor.authorCOOK, Neil
dc.contributor.authorEDWARDS, Billy
dc.contributor.authorHALLATT, Tim
dc.contributor.authorBOUCHY, François
dc.contributor.authorALLART, Romain
dc.contributor.authorMIGNON, Lucile
dc.contributor.authorBARON, Frédérique
dc.contributor.authorBARROS, Susana
dc.contributor.authorBENNEKE, Björn
dc.contributor.authorMARTINS, B.
dc.contributor.authorCHARNAY, Benjamin
dc.contributor.authorCOWAN, Nicolas
dc.contributor.authorDE MEDEIROS, J.
dc.contributor.authorDELFOSSE, Xavier
dc.contributor.authorDELGADO-MENA, Elisa
dc.contributor.authorDUMUSQUE, Xavier
dc.contributor.authorEHRENREICH, David
dc.contributor.authorHARA, Nathan
dc.contributor.authorLAFRENIÈRE, David
dc.contributor.authorFRENSCH, Yolanda
dc.contributor.authorHERNÁNDEZ, J.
dc.contributor.authorCURTO, Gaspare Lo
dc.contributor.authorMALO, Lison
dc.contributor.authorMELO, Claudio
dc.contributor.authorMOUNZER, Dany
dc.contributor.authorPASSEGER, Vera Maria
dc.contributor.authorPEPE, Francesco
dc.contributor.authorPOULIN-GIRARD, Anne-Sophie
dc.contributor.authorSANTOS, Nuno
dc.contributor.authorSOSNOWSKA, Danuta
dc.contributor.authorMASCAREÑO, Alejandro Suárez
dc.contributor.authorTHIBAULT, Simon
dc.contributor.authorVAULATO, Valentina
dc.contributor.authorWADE, Gregg
dc.contributor.authorWILDI, François
dc.date.issued2023
dc.description.abstractEnLHS 1140 b and c are two small temperate exoplanets transiting a nearby M4.5 dwarf. The planetary system was observed with multiple facilities since its discovery in 2017, including MEarth, $Spitzer$, HARPS, ESPRESSO, HST, and TESS, placing strong constraints on the physical parameters of the planets and star. Here, we reanalyse the publicly available 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. This analysis reduces radial velocity uncertainties by 60% compared with published values derived from the cross-correlation function method. This improvement, combined with updated stellar parameters, consolidates our knowledge on the mass of LHS 1140 b (5.60$\pm$0.19 M$_{\oplus}$) and LHS 1140 c (1.91$\pm$0.06 M$_{\oplus}$) with unprecedented precision (3%). A joint analysis of transit data obtained with $Spitzer$, HST, and TESS allows us to refine the planetary radius for b (1.730$\pm$0.025 R$_{\oplus}$) and c (1.272$\pm$0.026 R$_{\oplus}$). 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 habitable zone planet is unlikely to be a rocky super-Earth, but rather a mini-Neptune with a $\sim$0.1% H/He-rich mass envelope or a water world with a water-mass fraction between 9 and 19% depending on the atmospheric composition and relative abundance of Fe and Mg. Although LHS 1140 c remains consistent with a rocky planet, we detect a 4$σ$ discrepancy in the transit depths measured by $Spitzer$ and TESS. Finally, we find no evidence of the candidate LHS 1140 d and attribute this 80-day signal to stellar activity.
dc.language.isoen
dc.subject.enEarth and Planetary Astrophysics (astro-ph.EP)
dc.subject.enFOS: Physical sciences
dc.title.enNew Mass and Radius Constraints on the LHS 1140 Planets -- LHS 1140 b is Either a Temperate Mini-Neptune or a Water World
dc.typeDocument de travail - Pré-publication
dc.typePrepublication/Preprint
dc.identifier.doi10.48550/arXiv.2310.15490
dc.subject.halPlanète et Univers [physics]
dc.identifier.arxiv2310.15490
hal.identifierhal-04263311
hal.version1
hal.origin.linkhttps://hal.archives-ouvertes.fr//hal-04263311v1
bordeaux.COinSctx_ver=Z39.88-2004&rft_val_fmt=info:ofi/fmt:kev:mtx:journal&rft.date=2023&rft.au=CADIEUX,%20Charles&PLOTNYKOV,%20Mykhaylo&DOYON,%20Ren%C3%A9&VALENCIA,%20Diana&JAHANDAR,%20Farbod&rft.genre=preprint&unknown


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