TOI-1801 b: A temperate mini-Neptune around a young M0.5 dwarf
Journal article, 2023

We report the discovery, mass, and radius determination of TOI-1801 b, a temperate mini-Neptune around a young M dwarf. TOI-1801 b was observed in TESS sectors 22 and 49, and the alert that this was a TESS planet candidate with a period of 21.3 days went out in April 2020. However, ground-based follow-up observations, including seeing-limited photometry in and outside transit together with precise radial velocity (RV) measurements with CARMENES and HIRES revealed that the true period of the planet is 10.6 days. These observations also allowed us to retrieve a mass of 5.74 +/- 1.46 M-circle plus, which together with a radius of 2.08 +/- 0.12 R-circle plus, means that TOI-1801 b is most probably composed of water and rock, with an upper limit of 2% by mass of H-2 in its atmosphere. The stellar rotation period of 16 days is readily detectable in our RV time series and in the ground-based photometry. We derived a likely age of 600-800 Myr for the parent star TOI-1801, which means that TOI-1801 b is the least massive young mini-Neptune with precise mass and radius determinations. Our results suggest that if TOI-1801 b had a larger atmosphere in the past, it must have been removed by some evolutionary mechanism on timescales shorter than 1 Gyr.

planets and satellites: individual: TOI-1801

techniques: spectroscopic

planets and satellites: atmospheres

techniques: radial velocities

stars: low-mass

planetary systems

Author

M. Mallorquin

Instituto de Astrofísica de Canarias

University of La Laguna

E. Goffo

University of Turin

Thüringer Landessternwarte Tautenburg

E. Palle

Instituto de Astrofísica de Canarias

University of La Laguna

N. Lodieu

University of La Laguna

Instituto de Astrofísica de Canarias

V. J. S. Bejar

University of La Laguna

Instituto de Astrofísica de Canarias

H. Isaacson

University of California at Berkeley

M. R. Zapatero Osorio

Spanish National Research Council (CSIC)

S. Dreizler

University of Göttingen

S. Stock

Heidelberg University

R. Luque

University of Chicago

F. Murgas

University of La Laguna

Instituto de Astrofísica de Canarias

L. Pena

Spanish National Research Council (CSIC)

J. Sanz-Forcada

Spanish National Research Council (CSIC)

Giuseppe Morello

Chalmers, Space, Earth and Environment, Astronomy and Plasmaphysics

D. R. Ciardi

California Institute of Technology (Caltech)

E. Furlan

California Institute of Technology (Caltech)

K. A. Collins

Harvard-Smithsonian Center for Astrophysics

E. Herrero

Centre Tecnològic de Telecomunicacions de Catalunya (CTTC)

S. Vanaverbeke

KU Leuven

AstroLAB IRIS

Vereniging Voor Sterrenkunde (VVS)

P. Plavchan

George Mason University

N. Narita

University of Tokyo

Instituto de Astrofísica de Canarias

Astrobiology Center, Japan

A. Schweitzer

Hamburg Observatory

M. Perez-Torres

Spanish National Research Council (CSIC)

A. Quirrenbach

Heidelberg University

J. Kemmer

Heidelberg University

A. P. Hatzes

Thüringer Landessternwarte Tautenburg

A. Howard

University of California at Berkeley

M. Schlecker

University of Arizona

S. Reffert

Heidelberg University

E. Nagel

University of Göttingen

J. C. Morales

Spanish National Research Council (CSIC)

Centre Tecnològic de Telecomunicacions de Catalunya (CTTC)

J. Orell-Miquel

University of La Laguna

Instituto de Astrofísica de Canarias

C. Duque-Arribas

Complutense University

I. Carleo

University of La Laguna

Instituto de Astrofísica de Canarias

C. Cifuentes

Spanish National Research Council (CSIC)

G. Nowak

Instituto de Astrofísica de Canarias

University of La Laguna

Nicolaus Copernicus University

I. Ribas

Spanish National Research Council (CSIC)

Centre Tecnològic de Telecomunicacions de Catalunya (CTTC)

A. Reiners

University of Göttingen

P. J. Amado

Spanish National Research Council (CSIC)

J. A. Caballero

Spanish National Research Council (CSIC)

Th. Henning

Max Planck Society

V. Pinter

Calar Alto Astronomical Observatory

J. M. Akana Murphy

University of California at Santa Cruz

C. Beard

University of California at Irvine (UCI)

S. Blunt

California Institute of Technology (Caltech)

C. L. Brinkman

University of California at Riverside

University of Hawaii

B. Cale

California Institute of Technology (Caltech)

A. Chontos

Princeton University

University of Hawaii

K. I. Collins

George Mason University

I. J. M. Crossfield

University of Kansas

F. Dai

California Institute of Technology (Caltech)

P. A. Dalba

University of California at Santa Cruz

S. Dufoer

Vereniging Voor Sterrenkunde (VVS)

M. El Mufti

George Mason University

N. Espinoza

Space Telescope Science Institute (STScI)

T. Fetherolf

University of California at Riverside

A. Fukui

University of Tokyo

Instituto de Astrofísica de Canarias

S. Giacalone

University of California at Berkeley

C. Gnilka

National Aeronautics and Space Administration (NASA)

E. Gonzales

University of California at Santa Cruz

S. K. Grunblatt

Johns Hopkins University

S. Howell

National Aeronautics and Space Administration (NASA)

D. Huber

University of Hawaii

The University of Sydney

S. R. Kane

University of California at Riverside

J. P. de Leon

University of Tokyo

J. Lubin

University of California at Irvine (UCI)

M. G. MacDougall

University of California at Los Angeles

B. Massey

Villa’39 Observatory

D. Montes

Complutense University

M. Mori

University of Tokyo

H. Parviainen

Instituto de Astrofísica de Canarias

University of La Laguna

V. M. Passegger

University of La Laguna

Instituto de Astrofísica de Canarias

University of Oklahoma

A. S. Polanski

University of Kansas

P. Robertson

University of California at Irvine (UCI)

R. P. Schwarz

Harvard-Smithsonian Center for Astrophysics

G. Srdoc

Kotizarovci Observatory

H. M. Tabernero

Spanish National Research Council (CSIC)

A. Tanner

Mississippi State University

E. Turtelboom

University of California at Berkeley

J. Van Zandt

University of California at Los Angeles

L. Weiss

University of Notre Dame

M. Zechmeister

University of Göttingen

Astronomy and Astrophysics

0004-6361 (ISSN) 1432-0746 (eISSN)

Vol. 680 A76

Subject Categories (SSIF 2011)

Astronomy, Astrophysics and Cosmology

DOI

10.1051/0004-6361/202347346

More information

Latest update

3/9/2025 1