@article{79c45b1a9b404667be53509c689f5ec7,
title = "GJ 3090 b: one of the most favourable mini-Neptune for atmospheric characterisation",
abstract = "We report the detection of GJ 3090 b (TOI-177.01), a mini-Neptune on a 2.9-day orbit transiting a bright (K = 7.3 mag) M2 dwarf located at 22 pc. The planet was identified by the Transiting Exoplanet Survey Satellite and was confirmed with the High Accuracy Radial velocity Planet Searcher radial velocities. Seeing-limited photometry and speckle imaging rule out nearby eclipsing binaries. Additional transits were observed with the LCOGT, Spitzer, and ExTrA telescopes. We characterise the star to have a mass of 0.519 ± 0.013 M{\^a} ? ? and a radius of 0.516 ± 0.016 R{\^a} ? ? . We modelled the transit light curves and radial velocity measurements and obtained a planetary mass of 3.34 ± 0.72 ME, a radius of 2.13 ± 0.11 RE, and a mean density of 1.89-0.45+0.52 g cm-3. The low density of the planet implies the presence of volatiles, and its radius and insolation place it immediately above the radius valley at the lower end of the mini-Neptune cluster. A coupled atmospheric and dynamical evolution analysis of the planet is inconsistent with a pure H-He atmosphere and favours a heavy mean molecular weight atmosphere. The transmission spectroscopy metric of 221-46+66 means that GJ 3090 b is the second or third most favorable mini-Neptune after GJ 1214 b whose atmosphere may be characterised. At almost half the mass of GJ 1214 b, GJ 3090 b is an excellent probe of the edge of the transition between super-Earths and mini-Neptunes. We identify an additional signal in the radial velocity data that we attribute to a planet candidate with an orbital period of 13 days and a mass of 17.1-3.2+8.9 ME, whose transits are not detected.",
keywords = "Planetary systems, Stars: individual: GJ 3090, Techniques: photometric, Techniques: radial velocities",
author = "Almenara, {J. M.} and X. Bonfils and Otegi, {J. F.} and O. Attia and M. Turbet and N. Astudillo-Defru and Collins, {K. A.} and Polanski, {A. S.} and V. Bourrier and C. Hellier and C. Ziegler and F. Bouchy and C. Briceno and D. Charbonneau and M. Cointepas and Collins, {K. I.} and I. Crossfield and X. Delfosse and Diaz, {R. F.} and C. Dorn and Doty, {J. P.} and T. Forveille and G. Gaisn{\'e} and T. Gan and R. Helled and K. Hesse and Jenkins, {J. M.} and Jensen, {E. L.N.} and Latham, {D. W.} and N. Law and Mann, {A. W.} and S. Mao and B. McLean and F. Murgas and G. Myers and S. Seager and A. Shporer and Tan, {T. G.} and Twicken, {J. D.} and J. Winn",
note = "Funding Information: Funding for the TESS mission is provided by NASA{\textquoteright}s Science Mission Directorate. We acknowledge the use of public TESS data from pipelines at the TESS Science Office and at the TESS Science Processing Operations Center. This research has made use of the Exoplanet Follow-up Observation Program website, which is operated by the California Institute of Technology, under contract with the National Aeronautics and Space Administration under the Exoplanet Exploration Program. Resources supporting this work were provided by the NASA High-End Computing (HEC) Program through the NASA Advanced Supercomputing (NAS) Division at Ames Research Center for the production of the SPOC data products. This paper includes data collected by the TESS mission that are publicly available from the Mikulski Archive for Space Telescopes (MAST). We are grateful to the ESO/La Silla staff for their support. This work has made use of data from the European Space Agency (ESA) mission Gaia ( https://www.cosmos.esa.int/gaia ), processed by the Gaia Data Processing and Analysis Consortium (DPAC, https://www.cosmos.esa.int/web/gaia/dpac/consortium ). Funding for the DPAC has been provided by national institutions, in particular the institutions participating in the Gaia Multilateral Agreement. This work makes use of observations from the LCOGT network. Part of the LCOGT telescope time was granted by NOIRLab through the Mid-Scale Innovations Program (MSIP). MSIP is funded by NSF. Based in part on observations obtained at the Southern Astrophysical Research (SOAR) telescope, which is a joint project of the Minist{\'e}rio da Ci{\^e}ncia, Tecnologia e Inova{\c c}{\^o}es (MCTI/LNA) do Brasil, the US National Science Foundation s NOIRLab, the University of North Carolina at Chapel Hill (UNC), and Michigan State University (MSU). This work has been supported by agrant from Labex OSUG@2020 (Investissements d{\textquoteright}avenir-ANR10LABX56). Based on data collected under the ExTrA project at the ESO La Silla Paranal Observatory. ExTrA is a project of Institut de Plan{\'e}tologie et d Astrophysique de Grenoble (IPAG/CNRS/UGA), funded by the European Research Council under the ERC Grant Agreement n. 337591-ExTrA. O.A., V.B. and M.T.{\textquoteright}s work has been carried out in the frame of the National Centre for Competence in Research PlanetS supported by the Swiss National Science Foundation (SNSF). O.A. and V.B. acknowledge funding from the European Research Council (ERC) under the European Union{\textquoteright}s Horizon 2020 research and innovation programme (project Spice Dune; grant agreement no. 947634). M.T. thanks the Gruber Foundation for its support to this research. N.A.-D. acknowledges the support of FONDECYT project 3180063. Publisher Copyright: {\textcopyright} J. M. Almenara et al. 2022.",
year = "2022",
month = sep,
day = "1",
doi = "10.1051/0004-6361/202243975",
language = "English (US)",
volume = "665",
journal = "Astronomy and Astrophysics",
issn = "0004-6361",
publisher = "EDP Sciences",
}