K2-280 b - a low density warm sub-Saturn around a mildly evolved star
Journal article, 2020

We present an independent discovery and detailed characterization of K2-280 b, a transiting low density warm sub-Saturn in a 19.9-d moderately eccentric orbit (e = 0.35(-0.04)(+0.05)) from K2 campaign 7. A joint analysis of high precision HARPS, HARPS-N, and FIES radial velocity measurements and K2 photometric data indicates that K2-280 b has a radius of R-b = 7.50 +/- 0.44 R-circle plus and a mass of M-b = 37.1 +/- 5.6 M-circle plus, yielding a mean density of rho(b) = 0.48(-0.10)(+0.13) g cm(-3). The host star is a mildly evolved G7 star with an effective temperature of T-eff = 5500 +/- 100 K, a surface gravity of log g(star) = 4.21 +/- 0.05 (cgs), and an iron abundance of [Fe/H] = 0.33 +/- 0.08 dex, and with an inferred mass of M-star = 1.03 +/- 0.03 M-circle dot and a radius of R-star = 1.28 +/- 0.07 R-circle dot. We discuss the importance of K2-280 b for testing formation scenarios of sub-Saturn planets and the current sample of this intriguing group of planets that are absent in the Solar system.

techniques: radial velocities

techniques: spectroscopic

techniques: photometric

stars: individual: (EPIC 216494238, K2-280)

planets and satellites: detection

Author

Grzegorz Nowak

Instituto de Astrofísica de Canarias

University of La Laguna

Enric Palle

University of La Laguna

Instituto de Astrofísica de Canarias

Davide Gandolfi

University of Turin

Hans J. Deeg

Instituto de Astrofísica de Canarias

University of La Laguna

Teruyuki Hirano

Tokyo Institute of Technology

Oscar Barragan

University of Oxford

University of Turin

Masayuki Kuzuhara

National Institutes of Natural Sciences

Fei Dai

Princeton University

Massachusetts Institute of Technology (MIT)

Rafael Luque

University of La Laguna

Instituto de Astrofísica de Canarias

Carina Persson

Chalmers, Space, Earth and Environment, Astronomy and Plasmaphysics, Galactic Astrophysics

Malcolm Fridlund

Chalmers, Space, Earth and Environment, Astronomy and Plasmaphysics, Galactic Astrophysics

Marshall C. Johnson

Las Cumbres Observatory Global Telescope Network

Judith Korth

University of Cologne

John H. Livingston

University of Tokyo

Sascha Grziwa

University of Cologne

Savita Mathur

Instituto de Astrofísica de Canarias

University of La Laguna

Artie P. Hatzes

Thüringer Landessternwarte Tautenburg

Jorge Prieto-Arranz

University of La Laguna

Instituto de Astrofísica de Canarias

David Nespral

Instituto de Astrofísica de Canarias

University of La Laguna

Diego Hidalgo

University of La Laguna

Instituto de Astrofísica de Canarias

Maria Hjorth

Aarhus University

Simon Albrecht

Aarhus University

Vincent Van Eylen

Princeton University

Kristine W. F. Lam

Technische Universität Berlin

William D. Cochran

The University of Texas at Austin

Massimiliano Esposito

Thüringer Landessternwarte Tautenburg

Szilard Csizmadia

German Aerospace Center (DLR)

Eike W. Guenther

Thüringer Landessternwarte Tautenburg

Petr Kabath

Czech Academy of Sciences

Pere Blay

Valencian International University

Rafael Brahm

Millennium Institute of Astrophysics

Adolfo Ibáñez University

Andres Jordan

Adolfo Ibáñez University

Millennium Institute of Astrophysics

Nestor Espinoza

Max Planck Society

Felipe Rojas

Millennium Institute of Astrophysics

Pontificia Universidad Catolica de Chile

Nuria Casasayas Barris

Instituto de Astrofísica de Canarias

University of La Laguna

Florian Rodler

European Southern Observatory Santiago

Roi Alonso Sobrino

University of La Laguna

Instituto de Astrofísica de Canarias

J. Cabrera

German Aerospace Center (DLR)

Ilaria Carleo

Wesleyan University

Alexander Chaushev

Technische Universität Berlin

Jerome de Leon

University of Tokyo

Philipp Eigmueller

German Aerospace Center (DLR)

Michael Endl

The University of Texas at Austin

Anders Erikson

German Aerospace Center (DLR)

Akihiko Fukui

National Institutes of Natural Sciences

Iskra Georgieva

Chalmers, Space, Earth and Environment, Astronomy and Plasmaphysics, Galactic Astrophysics

Lucia Gonzalez-Cuesta

Instituto de Astrofísica de Canarias

University of La Laguna

Emil Knudstrup

Aarhus University

Mikkel N. Lund

Aarhus University

Pilar Montanes Rodriguez

Instituto de Astrofísica de Canarias

University of La Laguna

Felipe Murgas

University of La Laguna

Instituto de Astrofísica de Canarias

Norio Narita

Instituto de Astrofísica de Canarias

Japan Science and Technology Agency

National Institutes of Natural Sciences

Prajwal Niraula

Massachusetts Institute of Technology (MIT)

Martin Paetzold

University of Cologne

Heike Rauer

Technische Universität Berlin

German Aerospace Center (DLR)

Seth Redfield

Wesleyan University

Ignasi Ribas

Spanish National Research Council (CSIC)

Institute of Space Studies of Catalonia (IEEC)

Marek Skarka

Czech Academy of Sciences

Masaryk University

Alexis M. S. Smith

German Aerospace Center (DLR)

Jano Subjak

Czech Academy of Sciences

Charles University

Monthly Notices of the Royal Astronomical Society

0035-8711 (ISSN) 1365-2966 (eISSN)

Vol. 497 4 4423-4435

Subject Categories

Astronomy, Astrophysics and Cosmology

Other Earth and Related Environmental Sciences

Materials Chemistry

DOI

10.1093/mnras/staa2077

More information

Latest update

10/13/2021