The discovery of a planetary candidate around the evolved low-mass Kepler giant star HD 175370
Artikel i vetenskaplig tidskrift, 2017

We report on the discovery of a planetary companion candidate with a minimum mass M sin i = 4.6 +/- 1.0 M-Jupiter orbiting the K2 III giant star HD 175370 (KIC 007940959). This star was a target in our programme to search for planets around a sample of 95 giant stars observed with Kepler. This detection was made possible using precise stellar radial velocity measurements of HD 175370 taken over five years and four months using the coude echelle spectrograph of the 2-m Alfred Jensch Telescope and the fibre-fed echelle spectrograph High Efficiency and Resolution Mercator Echelle Spectrograph of the 1.2-m Mercator Telescope. Our radial velocity measurements reveal a periodic (349.5 +/- 4.5 d) variation with a semi-amplitude K = 133 +/- 25 ms(-1), superimposed on a long-term trend. A low-mass stellar companion with an orbital period of similar to 88 yr in a highly eccentric orbit and a planet in a Keplerian orbit with an eccentricity e = 0.22 are the most plausible explanation of the radial velocity variations. However, we cannot exclude the existence of stellar envelope pulsations as a cause for the low-amplitude radial velocity variations and only future continued monitoring of this system may answer this uncertainty. From Kepler photometry, we find that HD 175370 is most likely a low-mass red giant branch or asymptotic giant branch star.

planetary systems

techniques: radial velocities

stars: individual: HD 175370 (KIC 007940959)

methods: data analysis

techniques: spectroscopic

methods: observational

Författare

M. Hrudkova

Isaac Newton Group

A. Hatzes

Thuringer Landessternwarte Tautenburg

R. Karjalainen

Isaac Newton Group

H. Lehmann

Thuringer Landessternwarte Tautenburg

S. Hekker

Max Planck-institutet

Aarhus Universitet

M. Hartmann

Thuringer Landessternwarte Tautenburg

A. Tkachenko

KU Leuven

S. Prins

KU Leuven

H. van Winckel

KU Leuven

R. De Nutte

Royal Observatory of Belgium

L. Dumortier

Royal Observatory of Belgium

Y. Fremat

Royal Observatory of Belgium

H. Hensberge

Royal Observatory of Belgium

A. Jorissen

Université libre de Bruxelles (ULB)

P. Lampens

Royal Observatory of Belgium

M. Laverick

KU Leuven

Robin Lombaert

Chalmers, Rymd- och geovetenskap, Onsala rymdobservatorium

P. I. Papics

KU Leuven

G. Raskin

KU Leuven

A. Sodor

Royal Observatory of Belgium

Konkoly Observatory Hungarian Academy of Sciences

A. Thoul

Universite de Liege

Kavli Institute for Theoretical Physics

S. Van Eck

Université libre de Bruxelles (ULB)

C. Waelkens

KU Leuven

Monthly Notices of the Royal Astronomical Society

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

Vol. 464 1018-1028

Ämneskategorier

Astronomi, astrofysik och kosmologi

DOI

10.1093/mnras/stw2379