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          Institute: MPI für Astronomie     Collection: Publikationen_mpia     Display Documents

ID: 276737.0, MPI für Astronomie / Publikationen_mpia
A substellar companion around the intermediate-mass giant star HD 11977
Authors:Setiawan, J.; Rodmann, J.; da Silva, L.; Hatzes, A. P.; Pasquini, L.; von der Lühe, O.; de Medeiros, J. R.; Döllinger, M. P.; Girardi, L.
Date of Publication (YYYY-MM-DD):2005
Title of Journal:Astronomy and Astrophysics
Journal Abbrev.:Astronomy and Astrophysics
Start Page:L31
End Page:L34
Review Status:Peer-review
Audience:Experts Only
Abstract / Description:We report the discovery of a substellar companion to the intermediate-mass star <ASTROBJ>HD 11977</ASTROBJ> (G5 III). Radial velocities of this star have been monitored for five years with FEROS at the 1.52-m ESO and later at the 2.2-m MPG/ESO telescope in La Silla, Chile. Based on the collected data we calculated an orbital solution with a period of P=711 days, a semi-amplitude of K1=105 m s-1, and an eccentricity of e=0.4. The period of the radial-velocity variation is longer than that of the estimated stellar rotation, rendering it unlikely that rotational modulation is the source of the variation in the radial velocity. This hypothesis is supported by the absence of a correlation between stellar activity indicators and radial-velocity variation. By determining a primary stellar mass of Mstar=1.91 Mâ_™, the best-fit minimum mass of the companion and semi-major axis of the orbit are m2sin{i}=6.54 MJup and a2=1.93 AU, respectively. An upper limit for the mass of the companion of m2 î«¥ 65.5 MJup has been calculated from Hipparcos astrometric measurements. Although the possibility of a brown-dwarf companion cannot be excluded, HD 11977 B is one of the few planet candidates detected around an intermediate-mass star. The progenitor main-sequence star of <ASTROBJ>HD 11977</ASTROBJ> is probably an A-type star. This discovery gives an indirect evidence for planetary companions around early type main-sequence stars.
Free Keywords:stars: general; stars: planetary system; stars: individual: HD 11977; technique: radial velocity
External Publication Status:published
Document Type:Article
Communicated by:N. N.
Affiliations:MPI für Astronomie
Identifiers:URL:http://adsabs.harvard.edu/cgi-bin/nph- bib_query?b... [ID No:1]
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