The Transiting Multi-planet System HD15337: Two Nearly Equal-mass Planets Straddling the Radius Gap
Journal article, 2019

We report the discovery of a super-Earth and a sub-Neptune transiting the star HD 15337 (TOI-402, TIC 120896927), a bright (V = 9) K1 dwarf observed by the Transiting Exoplanet Survey Satellite (TESS) in Sectors 3 and 4. We combine the TESS photometry with archival High Accuracy Radial velocity Planet Searcher spectra to confirm the planetary nature of the transit signals and derive the masses of the two transiting planets. With an orbital period of 4.8 days, a mass of {7.51}-1.01+1.09 {M}\oplus and a radius of 1.64 ± 0.06 R ⊕, HD 15337 b joins the growing group of short-period super-Earths known to have a rocky terrestrial composition. The sub-Neptune HD 15337 c has an orbital period of 17.2 days, a mass of {8.11}-1.69+1.82 {{{M}}}\oplus , and a radius of 2.39 ± 0.12 R ⊕, suggesting that the planet might be surrounded by a thick atmospheric envelope. The two planets have similar masses and lie on opposite sides of the radius gap, and are thus an excellent testbed for planet formation and evolution theories. Assuming that HD 15337 c hosts a hydrogen-dominated envelope, we employ a recently developed planet atmospheric evolution algorithm in a Bayesian framework to estimate the history of the high-energy (extreme ultraviolet and X-ray) emission of the host star. We find that at an age of 150 Myr, the star possessed on average between 3.7 and 127 times the high-energy luminosity of the current Sun.

planets and satellites: fundamental parameters

planets and satellites: individual: HD15337 b & c

planetary systems

stars: fundamental parameters

planets and satellites: detection

Author

D. Gandolfi

University of Turin

L. Fossati

IWF

J. H. Livingston

University of Tokyo

K.G. Stassun

Vanderbilt University

Fisk University

S. Grziwa

University of Cologne

O. Barragan

University of Oxford

Malcolm Fridlund

Leiden University

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

D. Kubyshkina

IWF

Carina Persson

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

F. Dai

Princeton University

Massachusetts Institute of Technology (MIT)

K. W. F. Lam

Technische Universität Berlin

S. Albrecht

Aarhus University

N. Batalha

University of California

P. G. Beck

Instituto Astrofisico de Canarias

University of La Laguna

A. B. Justesen

Aarhus University

J. Cabrera

German Aerospace Center (DLR)

S. P. Cartwright

University of La Laguna

W. D. Cochran

The University of Texas at Austin

Sz. Csizmadia

German Aerospace Center (DLR)

M. D. Davies

NASA Ames Research Center

H. J. Deeg

University of La Laguna

Instituto Astrofisico de Canarias

Ph. Eigmüller

German Aerospace Center (DLR)

M. Endl

The University of Texas at Austin

A. Erikson

German Aerospace Center (DLR)

M. Esposito

Thüringer Landessternwarte Tautenburg

R. A. García

Paris Diderot University

R. Goeke

Massachusetts Institute of Technology (MIT)

L. González-Cuesta

Instituto Astrofisico de Canarias

University of La Laguna

E. W. Guenther

Thüringer Landessternwarte Tautenburg

A. P. Hatzes

Thüringer Landessternwarte Tautenburg

D. Hidalgo

Instituto Astrofisico de Canarias

T. Hirano

Tokyo Institute of Technology

M. Hjorth

Aarhus University

P. Kabath

Czech Academy of Sciences

E. Knudstrup

Aarhus University

J. Korth

Czech Academy of Sciences

J. Li

NASA Ames Research Center

R. Luque

Instituto Astrofisico de Canarias

University of La Laguna

S. Mathur

Instituto Astrofisico de Canarias

University of La Laguna

P. Montanes Rodriguez

University of La Laguna

Instituto Astrofisico de Canarias

N. Narita

University of Tokyo

National Institutes of Natural Sciences

Japan Science and Technology Agency

Instituto Astrofisico de Canarias

D. Nespral

University of La Laguna

Instituto Astrofisico de Canarias

P. Niraula

Massachusetts Institute of Technology (MIT)

G. Nowak

Instituto Astrofisico de Canarias

University of La Laguna

E. Palle

University of La Laguna

Instituto Astrofisico de Canarias

M. Pätzold

Fisk University

J. Prieto-Arranz

Instituto Astrofisico de Canarias

University of La Laguna

H. Rauer

FU Berlin

German Aerospace Center (DLR)

Technische Universität Berlin

S. Redfield

Wesleyan University

I Ribas

Institute of Space Sciences (ICE) - CSIC

Institute of Space Studies of Catalonia (IEEC)

M. Skarka

Masaryk University

Czech Academy of Sciences

A. M S Smith

German Aerospace Center (DLR)

P. Rowden

Open University

G. Torres

Harvard-Smithsonian Center for Astrophysics

Vincent Van Eylen

Princeton University

Michael L. Vezie

Massachusetts Institute of Technology (MIT)

Astrophysical Journal Letters

2041-8205 (ISSN) 2041-8213 (eISSN)

Vol. 876 2 L24

Exoplanets from space – CHEOPS and PLATO, ESA’s next two projects

Swedish National Space Board, 2017-01-01 -- 2022-12-31.

Subject Categories

Astronomy, Astrophysics and Cosmology

Roots

Basic sciences

DOI

10.3847/2041-8213/ab17d9

More information

Latest update

7/16/2019