Volume 653, September 2021
|Number of page(s)||21|
|Section||Planets and planetary systems|
|Published online||07 September 2021|
TOI-674b: An oasis in the desert of exo-Neptunes transiting a nearby M dwarf★
Instituto de Astrofísica de Canarias (IAC),
2 Departamento de Astrofísica, Universidad de La Laguna (ULL), 38206 La Laguna, Tenerife, Spain
3 Departamento de Matemática y Física Aplicadas, Universidad Católica de la Santísima Concepción, Alonso de Rivera 2850, Concepción, Chile
4 Univ. Grenoble Alpes, CNRS, IPAG, 38000 Grenoble, France
5 Department of Physics and Astronomy, University of Kansas, Lawrence, KS, USA
6 Department of Astronomy, University of Tokyo 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-0033, Japan
7 Vanderbilt University, Department of Physics & Astronomy, 6301 Stevenson Center Ln., Nashville, TN 37235, USA
8 Observatoire de l’Université de Genève, Chemin des Maillettes 51, 1290 Versoix, Switzerland
9 NASA Ames Research Center, Moffett Field, CA, 94035, USA
10 Caltech/IPAC, 1200 E. California Blvd. Pasadena, CA 91125, USA
11 Department of Astronomy and Astrophysics, University of California, Santa Cruz, CA 95064, USA
12 U.S. Naval Observatory, Washington, DC 20392, USA
13 NASA Goddard Space Flight Center, 8800 Greenbelt Rd, Greenbelt, MD 20771, USA
14 Center for Astrophysics | Harvard & Smithsonian, 60 Garden Street, Cambridge, MA 02138, USA
15 George Mason University, 4400 University Drive, Fairfax, VA 22030, USA
16 Department of Physics & Astronomy, Swarthmore College, Swarthmore, PA 19081, USA
17 El Sauce Observatory, Coquimbo Province, Chile
18 Space Sciences, Technologies and Astrophysics Research (STAR) Institute, Université de Liège, 19C Allée du 6 Août, 4000 Liège, Belgium
19 Astrobiology Research Unit, Université de Liège, 19C Allée du 6 Août, 4000 Liège, Belgium
20 Oukaimeden Observatory, High Energy Physics and Astrophysics Laboratory, Cadi Ayyad University, Marrakech, Morocco
21 International Center for Advanced Studies (ICAS) and ICIFI(CONICET), ECyT-UNSAM, Campus Miguelete, 25 de Mayo y Francia (1650), Buenos Aires, Argentina
22 Université de Montréal, Département de Physique & Institut de Recherche sur les Exoplanètes, Montréal, QC H3C 3J7, Canada
23 European Southern Observatory, Alonso de Córdova 3107, Vitacura, Región Metropolitana, Chile
24 Instituto de Astrofísica e Ciências do Espaço, Universidade do Porto, CAUP, Rua das Estrelas, 4150-762 Porto, Portugal
25 Departamento de Física e Astronomia, Faculdade de Ciências, Universidade do Porto, Rua do Campo Alegre, 4169-007 Porto, Portugal
26 Department of Physics and Kavli Institute for Astrophysics and Space Research, Massachusetts Institute of Technology, Cambridge, MA 02139, USA
27 Department of Earth, Atmospheric and Planetary Sciences, Massachusetts Institute of Technology, Cambridge, MA 02139, USA
28 Department of Aeronautics and Astronautics, MIT, 77 Massachusetts Avenue, Cambridge, MA 02139, USA
29 Department of Astrophysical Sciences, Princeton University, NJ 08544, USA
30 SETI Institute, 189 Bernardo Ave, Suite 200, Mountain View, CA 94043, USA
31 Space Telescope Science Institute, Baltimore, MD 21218, USA
32 Department of Earth and Planetary Sciences, University of California, Riverside, CA 92521, USA
33 Jet Propulsion Laboratory, California Institute of Technology, 4800 Oak Grove Drive, Pasadena, CA 91109, USA
34 Department of Physics and Astronomy, University of New Mexico, 210 Yale Blvd NE, Albuquerque, NM 87106, USA
35 Department of Space, Earth and Environment, Astronomy and Plasma Physics, Chalmers University of Technology, 412 96 Gothenburg, Sweden
Accepted: 1 June 2021
Context. The NASA mission TESS is currently doing an all-sky survey from space to detect transiting planets around bright stars. As part of the validation process, the most promising planet candidates need to be confirmed and characterized using follow-up observations.
Aims. In this article, our aim is to confirm the planetary nature of the transiting planet candidate TOI-674b using spectroscopic and photometric observations.
Methods. We use TESS, Spitzer, ground-based light curves, and HARPS spectrograph radial velocity measurements to establish the physical properties of the transiting exoplanet candidate TOI-674b. We perform a joint fit of the light curves and radial velocity time series to measure the mass, radius, and orbital parameters of the candidate.
Results. We confirm and characterize TOI-674b, a low-density super-Neptune transiting a nearby M dwarf. The host star (TIC 158588995, V = 14.2 mag, J = 10.3 mag) is characterized by its M2V spectral type with M⋆ = 0.420 ± 0.010 M⊙, R⋆ = 0.420 ± 0.013 R⊙, and Teff = 3514 ± 57 K; it is located at a distance d = 46.16 ± 0.03 pc. Combining the available transit light curves plus radial velocity measurements and jointly fitting a circular orbit model, we find an orbital period of 1.977143 ± 3 × 10−6 days, a planetary radius of 5.25 ± 0.17 R⊕, and a mass of 23.6 ± 3.3 M⊕ implying a mean density of ρp =0.91 ± 0.15 g cm−3. A non-circular orbit model fit delivers similar planetary mass and radius values within the uncertainties. Given the measured planetary radius and mass, TOI-674b is one of the largest and most massive super-Neptune class planets discovered around an M-type star to date. It is found in the Neptunian desert, and is a promising candidate for atmospheric characterization using the James Webb Space Telescope.
Key words: planets and satellites: general / planets and satellites: gaseous planets / stars: individual: TOI-674 / techniques: photometric / techniques: radial velocities
© ESO 2021
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