TESS's first planet: A super-Earth transiting the naked-eye star π Mensae
Journal article, 2018

We report on the confirmation and mass determination of π Men c, the first transiting planet discovered by NASA's TESS space mission. π Men is a naked-eye (V = 5.65 mag), quiet G0 V star that was previously known to host a sub-stellar companion (π Men b) on a longperiod (Porb = 2091 days), eccentric (e = 0.64) orbit. Using TESS time-series photometry, combined with Gaia data, published UCLES at AAT Doppler measurements, and archival HARPS at ESO-3.6m radial velocities, we found that π Men c is a close-in planet with an orbital period of Porb = 6.27 days, a mass of Mc = 4.52 ± 0.81 Mo, and a radius of Rc = 2.06 ± 0.03 Ro. Based on the planet's orbital period and size, π Men c is a super-Earth located at, or close to, the radius gap, while its mass and bulk density suggest it may have held on to a significant atmosphere. Because of the brightness of the host star, this system is highly suitable for a wide range of further studies to characterize the planetary atmosphere and dynamical properties. We also performed an asteroseismic analysis of the TESS data and detected a hint of power excess consistent with the seismic values expected for this star, although this result depends on the photometric aperture used to extract the light curve. This marginal detection is expected from pre-launch simulations hinting at the asteroseismic potential of the TESS mission for longer, multi-sector observations and/or for more evolved bright stars.

Planets and satellites: terrestrial planets

Stars: fundamental parameters

Planetary systems

Planets and satellites: fundamental parameters

Planets and satellites: detection

Author

D. Gandolfi

University of Turin

O. Barragán

University of Turin

J.H. Livingston

University of Tokyo

Malcolm Fridlund

Leiden University

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

A.B. Justesen

Aarhus University

S. Redfield

Wesleyan University

L. Fossati

Institut fur Weltraumforschung

S. Mathur

University of La Laguna

Instituto Astrofisico de Canarias

S. Grziwa

University of Cologne

J. Cabrera

German Aerospace Center (DLR)

R. A. García

Paris Diderot University

University Paris-Saclay

Carina Persson

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

Vincent Van Eylen

Princeton University

A. Hatzes

Thüringer Landessternwarte Tautenburg

D. Hidalgo

Instituto Astrofisico de Canarias

University of La Laguna

Simon Albrecht

Aarhus University

L. Bugnet

Paris Diderot University

University Paris-Saclay

William D. Cochran

The University of Texas at Austin

Szilard Csizmadia

German Aerospace Center (DLR)

H. Deeg

Instituto Astrofisico de Canarias

University of La Laguna

P. Eigmüller

German Aerospace Center (DLR)

M. Endl

The University of Texas at Austin

Anders Erikson

German Aerospace Center (DLR)

M. Esposito

Thüringer Landessternwarte Tautenburg

E. W. Guenther

Thüringer Landessternwarte Tautenburg

Judith Korth

University of Cologne

R. Luque

University of La Laguna

Instituto Astrofisico de Canarias

P. M. Rodriguez

Instituto Astrofisico de Canarias

University of La Laguna

David Nespral

University of La Laguna

Instituto Astrofisico de Canarias

G. Nowak

Instituto Astrofisico de Canarias

University of La Laguna

Martin Pätzold

University of Cologne

J. Prieto-Arranz

University of La Laguna

Instituto Astrofisico de Canarias

Astronomy and Astrophysics

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

Vol. 619 L10

Subject Categories

Astronomy, Astrophysics and Cosmology

Roots

Basic sciences

DOI

10.1051/0004-6361/201834289

More information

Latest update

12/12/2018