The Astronomical Journal (Jan 2023)
TESS Spots a Super-puff: The Remarkably Low Density of TOI-1420b
- Stephanie Yoshida,
- Shreyas Vissapragada,
- David W. Latham,
- Allyson Bieryla,
- Daniel P. Thorngren,
- Jason D. Eastman,
- Mercedes López-Morales,
- Khalid Barkaoui,
- Charles Beichman,
- Perry Berlind,
- Lars A. Buchave,
- Michael L. Calkins,
- David R. Ciardi,
- Karen A. Collins,
- Rosario Cosentino,
- Ian J. M. Crossfield,
- Fei Dai,
- Victoria DiTomasso,
- Nicholas Dowling,
- Gilbert A. Esquerdo,
- Raquel Forés-Toribio,
- Adriano Ghedina,
- Maria V. Goliguzova,
- Eli Golub,
- Erica J. Gonzales,
- Ferran Grau Horta,
- Jesus Higuera,
- Nora Hoch,
- Keith Horne,
- Steve B. Howell,
- Jon M. Jenkins,
- Jessica Klusmeyer,
- Didier Laloum,
- Jack J. Lissauer,
- Sarah E. Logsdon,
- Luca Malavolta,
- Rachel A. Matson,
- Elisabeth C. Matthews,
- Kim K. McLeod,
- Jennifer V. Medina,
- Jose A. Muñoz,
- Hugh P. Osborn,
- Boris Safonov,
- Joshua Schlieder,
- Michael Schmidt,
- Heidi Schweiker,
- Sara Seager,
- Alessandro Sozzetti,
- Gregor Srdoc,
- Guđmundur Stefánsson,
- Ivan A. Strakhov,
- Stephanie Striegel,
- Joel Villaseñor,
- Joshua N. Winn
Affiliations
- Stephanie Yoshida
- ORCiD
- Center for Astrophysics ∣ Harvard & Smithsonian , 60 Garden Street, Cambridge, MA 02138, USA ; [email protected]
- Shreyas Vissapragada
- ORCiD
- Center for Astrophysics ∣ Harvard & Smithsonian , 60 Garden Street, Cambridge, MA 02138, USA ; [email protected]
- David W. Latham
- ORCiD
- Center for Astrophysics ∣ Harvard & Smithsonian , 60 Garden Street, Cambridge, MA 02138, USA ; [email protected]
- Allyson Bieryla
- ORCiD
- Center for Astrophysics ∣ Harvard & Smithsonian , 60 Garden Street, Cambridge, MA 02138, USA ; [email protected]
- Daniel P. Thorngren
- ORCiD
- Department of Physics & Astronomy, Johns Hopkins University , Baltimore, MD 21210, USA
- Jason D. Eastman
- ORCiD
- Center for Astrophysics ∣ Harvard & Smithsonian , 60 Garden Street, Cambridge, MA 02138, USA ; [email protected]
- Mercedes López-Morales
- ORCiD
- Center for Astrophysics ∣ Harvard & Smithsonian , 60 Garden Street, Cambridge, MA 02138, USA ; [email protected]
- Khalid Barkaoui
- ORCiD
- Astrobiology Research Unit, Université de Liège , 19C Allée du 6 Août, B-4000 Liège, Belgium; Department of Earth, Atmospheric, and Planetary Sciences, Massachusetts Institute of Technology , Cambridge, MA 02139, USA; Instituto de Astrofísica de Canarias (IAC) , Calle Vía Láctea s/n, E-38200, La Laguna, Tenerife, Spain
- Charles Beichman
- ORCiD
- Infrared Processing and Analysis Center, California Institute of Technology , 1200 East California Boulevard, Pasadena, CA 91125, USA
- Perry Berlind
- Center for Astrophysics ∣ Harvard & Smithsonian , 60 Garden Street, Cambridge, MA 02138, USA ; [email protected]
- Lars A. Buchave
- ORCiD
- DTU Space, National Space Institute, Technical University of Denmark , Elektrovej 327, DK-2800 Lyngby, Denmark
- Michael L. Calkins
- ORCiD
- Center for Astrophysics ∣ Harvard & Smithsonian , 60 Garden Street, Cambridge, MA 02138, USA ; [email protected]
- David R. Ciardi
- ORCiD
- Infrared Processing and Analysis Center, California Institute of Technology , 1200 East California Boulevard, Pasadena, CA 91125, USA
- Karen A. Collins
- ORCiD
- Center for Astrophysics ∣ Harvard & Smithsonian , 60 Garden Street, Cambridge, MA 02138, USA ; [email protected]
- Rosario Cosentino
- ORCiD
- Fundación Galileo Galilei-INAF , Rambla José Ana Fernandez Pérez 7, E-38712 Breña Baja, Tenerife, Spain
- Ian J. M. Crossfield
- Department of Physics and Astronomy, University of Kansas , Lawrence, KS 66045, USA
- Fei Dai
- ORCiD
- Division of Geological and Planetary Sciences, California Institute of Technology , 1200 East California Boulevard, Pasadena, CA 91125, USA; Department of Astronomy, California Institute of Technology , Pasadena, CA 91125, USA
- Victoria DiTomasso
- ORCiD
- Center for Astrophysics ∣ Harvard & Smithsonian , 60 Garden Street, Cambridge, MA 02138, USA ; [email protected]
- Nicholas Dowling
- University Observatory, Ludwig Maximilian University , Scheinerstrasse 1, D-81679 Munich, Germany
- Gilbert A. Esquerdo
- ORCiD
- Center for Astrophysics ∣ Harvard & Smithsonian , 60 Garden Street, Cambridge, MA 02138, USA ; [email protected]
- Raquel Forés-Toribio
- ORCiD
- Departamento de Astronomía y Astrofísica, Universidad de Valencia , E-46100 Burjassot, Valencia, Spain; Observatorio Astronómico, Universidad de Valencia , E-46980 Paterna, Valencia, Spain
- Adriano Ghedina
- ORCiD
- Fundación Galileo Galilei-INAF , Rambla José Ana Fernandez Pérez 7, E-38712 Breña Baja, Tenerife, Spain
- Maria V. Goliguzova
- ORCiD
- Sternberg Astronomical Institute Lomonosov Moscow State University 119992 , Moscow, Russia, Universitetskii prospekt, 13, Russia
- Eli Golub
- NSF’s National Optical-Infrared Astronomy Research Laboratory , 950 N. Cherry Avenue, Tucson, AZ 85719, USA
- Erica J. Gonzales
- ORCiD
- University of California , Santa Cruz, 1156 High Street, Santa Cruz, CA 95065, USA
- Ferran Grau Horta
- ORCiD
- Observatori de Ca l’Ou , Carrer de dalt 18, Sant Martí Sesgueioles E-08282, Barcelona, Spain
- Jesus Higuera
- ORCiD
- NSF’s National Optical-Infrared Astronomy Research Laboratory , 950 N. Cherry Avenue, Tucson, AZ 85719, USA
- Nora Hoch
- ORCiD
- Department of Astronomy, Wellesley College , Wellesley, MA 02481, USA
- Keith Horne
- ORCiD
- SUPA Physics and Astronomy, University of St Andrews , Fife, KY16 9SS, Scotland, UK
- Steve B. Howell
- ORCiD
- NASA Ames Research Center , Moffett Field, CA 94035 USA
- Jon M. Jenkins
- ORCiD
- NASA Ames Research Center , Moffett Field, CA 94035 USA
- Jessica Klusmeyer
- ORCiD
- NSF’s National Optical-Infrared Astronomy Research Laboratory , 950 N. Cherry Avenue, Tucson, AZ 85719, USA
- Didier Laloum
- Société Astronomique de France , 3 Rue Beethoven, F-75016 Paris, France
- Jack J. Lissauer
- ORCiD
- Space Science & Astrobiology Division, MS 245-3, NASA Ames Research Center , Moffett Field, CA 94035, USA
- Sarah E. Logsdon
- ORCiD
- NSF’s National Optical-Infrared Astronomy Research Laboratory , 950 N. Cherry Avenue, Tucson, AZ 85719, USA
- Luca Malavolta
- ORCiD
- Dipartimento di Fisica e Astronomia Galileo Galilei, Universita di Padova , Vicolo dell’Osservatorio 3, I-35122 Padova, Italy
- Rachel A. Matson
- The United States Naval Observatory , 3450 Massachusetts Avenue, NW, Washington, DC 20392, USA
- Elisabeth C. Matthews
- ORCiD
- Max-Planck-Institut für Astronomie , Königstuhl 17, D-69117 Heidelberg, Germany
- Kim K. McLeod
- ORCiD
- Department of Astronomy, Wellesley College , Wellesley, MA 02481, USA
- Jennifer V. Medina
- Space Telescope Science Institute , 3700 San Martin Drive, Baltimore, MD 21218, USA
- Jose A. Muñoz
- Departamento de Astronomía y Astrofísica, Universidad de Valencia , E-46100 Burjassot, Valencia, Spain; Observatorio Astronómico, Universidad de Valencia , E-46980 Paterna, Valencia, Spain
- Hugh P. Osborn
- ORCiD
- Department of Physics and Kavli Institute for Astrophysics and Space Research, Massachusetts Institute of Technology , Cambridge, MA 02139, USA; NCCR/Planet-S, Universität Bern , Gesellschaftsstrasse 6, 3012 Bern, Switzerland
- Boris Safonov
- ORCiD
- Sternberg Astronomical Institute Lomonosov Moscow State University 119992 , Moscow, Russia, Universitetskii prospekt, 13, Russia
- Joshua Schlieder
- ORCiD
- NASA Goddard Space Flight Center , 8800 Greenbelt Road, Greenbelt, MD 20771, USA
- Michael Schmidt
- University Observatory, Ludwig Maximilian University , Scheinerstrasse 1, D-81679 Munich, Germany
- Heidi Schweiker
- ORCiD
- NSF’s National Optical-Infrared Astronomy Research Laboratory , 950 N. Cherry Avenue, Tucson, AZ 85719, USA
- Sara Seager
- ORCiD
- Department of Earth, Atmospheric, and Planetary Sciences, Massachusetts Institute of Technology , Cambridge, MA 02139, USA; Department of Physics and Kavli Institute for Astrophysics and Space Research, Massachusetts Institute of Technology , Cambridge, MA 02139, USA; Department of Aeronautics and Astronautics, Massachusetts Institute of Technology , Cambridge, MA 02139, USA
- Alessandro Sozzetti
- ORCiD
- INAFOsservatorio Astrofisico di Torino , Via Osservatorio, 20, I-10025 Pino Torinese TO, Italy
- Gregor Srdoc
- Kotizarovci Observatory , Sarsoni 90, 51216 Viskovo, Croatia
- Guđmundur Stefánsson
- ORCiD
- Department of Astrophysical Sciences, Princeton University , 4 Ivy Lane, Princeton, NJ 08540, USA
- Ivan A. Strakhov
- ORCiD
- Sternberg Astronomical Institute Lomonosov Moscow State University 119992 , Moscow, Russia, Universitetskii prospekt, 13, Russia
- Stephanie Striegel
- ORCiD
- NASA Ames Research Center , Moffett Field, CA 94035 USA; SETI Institute , Mountain View, CA 94043 USA
- Joel Villaseñor
- Department of Physics and Kavli Institute for Astrophysics and Space Research, Massachusetts Institute of Technology , Cambridge, MA 02139, USA
- Joshua N. Winn
- ORCiD
- Department of Astrophysical Sciences, Princeton University , 4 Ivy Lane, Princeton, NJ 08540, USA
- DOI
- https://doi.org/10.3847/1538-3881/acf858
- Journal volume & issue
-
Vol. 166,
no. 5
p. 181
Abstract
We present the discovery of TOI-1420b, an exceptionally low-density ( ρ = 0.08 ± 0.02 g cm ^−3 ) transiting planet in a P = 6.96 days orbit around a late G-dwarf star. Using transit observations from TESS, LCOGT, Observatoire Privé du Mont, Whitin, Wendelstein, OAUV, Ca l’Ou, and KeplerCam, along with radial velocity observations from HARPS-N and NEID, we find that the planet has a radius of R _p = 11.9 ± 0.3 R _⊕ and a mass of M _p = 25.1 ± 3.8 M _⊕ . TOI-1420b is the largest known planet with a mass less than 50 M _⊕ , indicating that it contains a sizeable envelope of hydrogen and helium. We determine TOI-1420b’s envelope mass fraction to be ${f}_{\mathrm{env}}={82}_{-6}^{+7} \% $ , suggesting that runaway gas accretion occurred when its core was at most four to five times the mass of the Earth. TOI-1420b is similar to the planet WASP-107b in mass, radius, density, and orbital period, so a comparison of these two systems may help reveal the origins of close-in low-density planets. With an atmospheric scale height of 1950 km, a transmission spectroscopy metric of 580, and a predicted Rossiter–McLaughlin amplitude of about 17 m s ^−1 , TOI-1420b is an excellent target for future atmospheric and dynamical characterization.
Keywords
