@article{fdb509a897c54e9d9a1e9eb5e86fca5b,
title = "Two sub-Neptunes around the M dwarf TOI-1470",
abstract = "Aims. A transiting planet candidate with a sub-Neptune radius orbiting the nearby (d = 51.9 ± 0.07 pc) M1.5 V star TOI-1470 with a period of ∼2.5 d was announced by the NASA Transiting Exoplanet Survey Satellite (TESS), which observed the field of TOI-1470 in four different sectors. We aim to validate its planetary nature using precise radial velocities (RVs) taken with the CARMENES spectrograph. Methods. We obtained 44 RV measurements with CARMENES spanning eight months between 3 June 2020 and 17 January 2021. For a better characterization of the parent star activity, we also collected contemporaneous optical photometric observations at the Joan Or{\'o} and Sierra Nevada Observatories, and we retrieved archival photometry from the literature. We used ground-based photometric observations from MuSCAT and also from MuSCAT2 and MuSCAT3 to confirm the planetary transit signals. We performed a combined photometric and spectroscopic analysis by including Gaussian processes and Keplerian orbits to simultaneously account for the stellar activity and planetary signals. Results. We estimate that TOI-1470 has a rotation period of 29 ± 3d based on photometric and spectroscopic data. The combined analysis confirms the discovery of the announced transiting planet, TOI-1470 b, with an orbital period of 2.527093 ± 0.000003 d, a mass of 7.32-1.24+1.21M, and a radius of 2.18-0.04+0.04R. We also discover a second transiting planet that was not announced previously by TESS, TOI-1470 c, with an orbital period of 18.08816 ± 0.00006 d, a mass of 7.24-2.77+2.87M, and a radius of 2.47-0.02+0.02R. The two planets are placed on the same side of the radius valley of M dwarfs and lie between TOI-1470 and the inner border of its habitable zone.",
keywords = "Planetary systems, Stars: individual: TOI-1470, Stars: late-type, Techniques: photometric, Techniques: radial velocities",
author = "E. Gonz{\'a}lez-{\'A}lvarez and {Zapatero Osorio}, {M. R.} and Caballero, {J. A.} and B{\'e}jar, {V. J.S.} and C. Cifuentes and A. Fukui and E. Herrero and K. Kawauchi and Livingston, {J. H.} and L{\'o}pez-Gonz{\'a}lez, {M. J.} and G. Morello and F. Murgas and N. Narita and E. Pall{\'e} and Passegger, {V. M.} and E. Rodr{\'i}guez and C. Rodr{\'i}guez-L{\'o}pez and J. Sanz-Forcada and A. Schweitzer and Tabernero, {H. M.} and A. Quirrenbach and Amado, {P. J.} and D. Charbonneau and Ciardi, {D. R.} and S. Cikota and Collins, {K. A.} and Conti, {D. M.} and M. Fausnaugh and Hatzes, {A. P.} and C. Hedges and Th Henning and Jenkins, {J. M.} and Latham, {D. W.} and B. Massey and D. Moldovan and D. Montes and A. Panahi and A. Reiners and I. Ribas and Ricker, {G. R.} and S. Seager and A. Shporer and G. Srdoc and P. Tenenbaum and R. Vanderspek and Winn, {J. N.} and I. Fukuda and M. Ikoma and K. Isogai and Y. Kawai and M. Mori and M. Tamura and N. Watanabe",
note = "Funding Information: We thank the anonymous referee for helpful comments and suggestions, which helped to improve the manuscript. CARMENES is an instrument at the Centro Astron{\'o}mico Hispano en Andaluc{\'i}a (CAHA) at Calar Alto (Almer{\'i}a, Spain), operated jointly by the Junta de Andaluc{\'i}a and the Instituto de Astrof{\'i}sica de Andaluc{\'i}a (CSIC). CARMENES was funded by the German Max-Planck-Gesellschaft (MPG), the Spanish Consejo Superior de Investigaciones Cient{\'i}ficas (CSIC), the European Union through FEDER/ERF funds, and the members of the CARMENES Consortium (Max-Planck-Institut f{\"u}r Astronomie, Instituto de Astrof{\'i}sica de Andaluc{\'i}a, Landessternwarte Ko{\"o}nigstuhl, Institut de Ci{\`e}ncies de l{\textquoteright}Espai, Insitut f{\"u}r Astrophysik G{\"o}ttingen, Universidad, Complutense de Madrid, Th{\"u}ringer Landessternwarte Tautenburg, Instituto de Astrof{\'i}sica de Canarias, Hamburger Sternwarte, Centro de Astrobiolog{\'i}a and Centro Astron{\'o}mico Hispano en Andaluc{\'i}a), with additional contributions by the Spanish Ministry of Economy, the state of Baden-W{\"u}ttemberg, the Deutsche Forschungsge-meinschaft (DFG) through the Major Research Instrumentation Programme and Research Unit FOR2544 “Blue Planets around Red Stars”, the Klaus Tschira Foundation, and by the Junta de Andaluc{\'i}a. This work was based on data from the CARMENES data archive at CAB (CSIC-INTA). This research has made use of the NASA Exoplanet Archive, which is operated by the California Institute of Technology, under contract with the National Aeronautics and Space Administration under the Exoplanet Exploration Program. Funding for the TESS mission is provided by NASA{\textquoteright}s Science Mission Directorate. This paper includes data collected by the TESS mission that are publicly available from the Mikulski Archive for Space Telescopes. We acknowledge the use of public TESS data from pipelines at the TESS Science Office and at the TESS Science Processing Operations Center. 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 article is based on observations made with the MuSCAT2 instrument, developed by ABC, at Telescopio Carlos S{\'a}nchez operated on the island of Tenerife by the IAC in the Spanish Observatorio del Teide. This paper is based on observations made with the MuSCAT3 instrument, developed by the Astrobiology Center and under financial supports by JSPS KAKENHI (JP18H05439) and JST PRESTO (JPMJPR1775), at Faulkes Telescope North on Maui, HI, operated by the Las Cumbres Observatory. Data were partly collected with the 1.50 m telescope at the Observatorio de Sierra Nevada operated by the Instituto de Astrof{\'i}fica de Andaluc{\'i}a (IAA-CSIC). The Joan Or{\'o} Telescope (TJO) of the Montsec Observatory (OdM) is owned by the Generalitat de Catalunya and operated by the Institute for Space Studies of Catalonia (IEEC). We acknowledge the telescope operators from Observatori del Montsec, Observatorio de Sierra Nevada, and Centro Astron{\'o}mico Hispano en Andaluc{\'i}a (CAHA) at Calar Alto. We acknowledge financial support from the Agencia Estatal de Investigaci{\'o}n (AEI/10.13039/501100011033) of the Ministerio de Ciencia e Innovaci{\'o}n and the ERDF “A way of making Europe” through projects PID2019-109522GB-C5[1:4], PID2019-107061GB-C64, and PID2019-110689RB-100, and the Centre of Excellence “Severo Ochoa” and “Mar{\'i}a de Maeztu” awards to the Instituto de Astrof{\'i}sica de Canarias (CEX2019-000920-S), Instituto de Astrof{\'i}sica de Andaluc{\'i}a (SEV-2017-0709), and Centro de Astrobiolog{\'i}a (MDM-2017-0737); the Generalitat de Catalunya/CERCA programme; MEXT/JSPS KAKENHI through grants 15H02063, JP17H04574, JP18H05439, JP18H05442, JP20J21872, JP21K20376, and 22000005; and JST CREST through grant JPMJCR1761. Publisher Copyright: {\textcopyright} 2023 EDP Sciences. All rights reserved.",
year = "2023",
month = jul,
day = "1",
doi = "10.1051/0004-6361/202346292",
language = "English (US)",
volume = "675",
journal = "Astronomy and Astrophysics",
issn = "0004-6361",
publisher = "EDP Sciences",
}