HD 89345: A bright oscillating star hosting a transiting warm Saturn-sized planet observed by K2
Artikel i vetenskaplig tidskrift, 2018

We report the discovery and characterization of HD 89345b (K2-234b; EPIC 248777106b), a Saturn-sized planet orbiting a slightly evolved star. HD 89345 is a bright star (V = 9.3 mag) observed by the K2 mission with 1 min time sampling. It exhibits solar-like oscillations. We conducted asteroseismology to determine the parameters of the star, finding themass and radius to be 1.12-0.01+0.04M⊙and 1.657-0.004+0.020R⊙, respectively. The star appears to have recently left the main sequence, based on the inferred age, 9.4-1.3+0.4Gyr, and the non-detection of mixed modes. The star hosts a 'warm Saturn' (P = 11.8 d, Rp= 6.86 ± 0.14 R⊕). Radial-velocity follow-up observations performed with the FIbre-fed Echelle Spectrograph, HARPS, and HARPS-N spectrographs show that the planet has a mass of 35.7 ± 3.3 M⊕. The data also show that the planet's orbit is eccentric (e≈0.2). An investigation of the rotational splitting of the oscillation frequencies of the star yields no conclusive evidence on the stellar inclination angle. We further obtained Rossiter-McLaughlin observations, which result in a broad posterior of the stellar obliquity. The planet seems to confirm to the same patterns that have been observed for other sub-Saturns regarding planet mass and multiplicity, orbital eccentricity, and stellar metallicity.

Planets and satellites: formation

Asteroseismology

Planets and satellites: fundamental parameters

Planets and satellites: composition

Författare

Vincent Van Eylen

Universiteit Leiden

Fei Dai

Princeton University

Massachusetts Institute of Technology (MIT)

S. Mathur

Instituto Astrofisico de Canarias

Universidad de la Laguna

D. Gandolfi

Universita degli Studi di Torino

Simon Albrecht

Aarhus Universitet

Malcolm Fridlund

Chalmers, Rymd-, geo- och miljövetenskap, Astronomi och plasmafysik, Galaktisk astrofysik

Universiteit Leiden

R. A. García

Université Paris-Saclay

Le Commissariat à l’Énergie Atomique et aux Énergies Alternatives (CEA)

E. W. Guenther

Thüringer Landessternwarte Tautenburg

M. Hjorth

Aarhus Universitet

A.B. Justesen

Aarhus Universitet

J.H. Livingston

University of Tokyo

M. N. Lund

Aarhus Universitet

F. Pérez Hernández

Universidad de la Laguna

Instituto Astrofisico de Canarias

J. Prieto-Arranz

Universidad de la Laguna

Instituto Astrofisico de Canarias

C. Regulo

Universidad de la Laguna

Instituto Astrofisico de Canarias

L. Bugnet

Le Commissariat à l’Énergie Atomique et aux Énergies Alternatives (CEA)

Université Paris-Saclay

M.E. Everett

National Optical Astronomy Observatory

T. Hirano

Tokyo Institute of Technology

David Nespral

Instituto Astrofisico de Canarias

Universidad de la Laguna

G. Nowak

Universidad de la Laguna

Instituto Astrofisico de Canarias

E. Palle

Universidad de la Laguna

Instituto Astrofisico de Canarias

V. Silva Aguirre

Aarhus Universitet

T. Trifonov

Max Planck-institutet

J. N. Winn

Princeton University

O. Barragán

Universita degli Studi di Torino

P. G. Beck

Instituto Astrofisico de Canarias

Universidad de la Laguna

W. J. Chaplin

Aarhus Universitet

University of Birmingham

William D. Cochran

The University of Texas at Austin

Szilard Csizmadia

Deutsches Zentrums für Luft- und Raumfahrt (DLR)

H. Deeg

Instituto Astrofisico de Canarias

Universidad de la Laguna

M. Endl

The University of Texas at Austin

P. Heeren

Landessternwarte Heidelberg

S. Grziwa

Universität zu Köln

A. Hatzes

Thüringer Landessternwarte Tautenburg

D. Hidalgo

Instituto Astrofisico de Canarias

Universidad de la Laguna

Judith Korth

Universität zu Köln

S. Mathis

Université Paris-Saclay

Le Commissariat à l’Énergie Atomique et aux Énergies Alternatives (CEA)

P. Montanés Rodríguez

Universidad de la Laguna

Instituto Astrofisico de Canarias

Norio Narita

National Institutes of Natural Sciences

University of Tokyo

Martin Pätzold

Universität zu Köln

Carina Persson

Chalmers, Rymd-, geo- och miljövetenskap, Astronomi och plasmafysik, Galaktisk astrofysik

F. Rodler

European Southern Observatory Santiago

Alexis M. S. Smith

Deutsches Zentrums für Luft- und Raumfahrt (DLR)

Monthly Notices of the Royal Astronomical Society

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

Vol. 478 4 4866-4880

Exoplaneter från rymden - CHEOPS och PLATO

Rymdstyrelsen, 2017-01-01 -- 2022-12-31.

Ämneskategorier

Meteorologi och atmosfärforskning

Astronomi, astrofysik och kosmologi

Bioinformatik (beräkningsbiologi)

Infrastruktur

Onsala rymdobservatorium

DOI

10.1093/mnras/sty1390

Mer information

Senast uppdaterat

2018-10-12