ICATE   21876
INSTITUTO DE CIENCIAS ASTRONOMICAS, DE LA TIERRA Y DEL ESPACIO
Unidad Ejecutora - UE
artículos
Título:
Exploring the origin of magnetic fields in massive stars. II. New magnetic field measurements in cluster and field stars
Autor/es:
HUBRIG, S.; SCHÖLLER, M.; ILYIN, I.; KHARCHENKO, N. V.; OSKINOVA, L. M.; LANGER, N.; GONZÁLEZ, J.F.; KHOLTYGIN, A. F.; BRIQUET, M.; MAGORI COLLABORATION
Revista:
ASTRONOMY AND ASTROPHYSICS
Editorial:
EDP SCIENCES S A
Referencias:
Lugar: Paris; Año: 2013 vol. 551 p. 1 - 13
ISSN:
0004-6361
Resumen:
Context. Theories on the origin of magnetic fields in massive stars
remain poorly developed, because the properties of their magnetic field
as function of stellar parameters could not yet be investigated.
Additional observations are of utmost importance to constrain the
conditions that are conducive to magnetic fields and to determine first
trends about their occurrence rate and field strength distribution. Aims: To investigate whether magnetic fields in massive stars are
ubiquitous or appear only in stars with a specific spectral
classification, certain ages, or in a special environment, we acquired
67 new spectropolarimetric observations for 30 massive stars. Among the
observed sample, roughly one third of the stars are probable members of
clusters at different ages, whereas the remaining stars are field stars
not known to belong to any cluster or association. Methods:
Spectropolarimetric observations were obtained during four different
nights using the low-resolution spectropolarimetric mode of FOcal
Reducer low dispersion Spectrograph (FORS 2) mounted on the 8-m Antu
telescope of the VLT. Furthermore, we present a number of follow-up
observations carried out with the high-resolution spectropolarimeters
SOFIN mounted at the Nordic Optical Telescope (NOT) and HARPS mounted at
the ESO 3.6 m between 2008 and 2011. To assess the membership in open
clusters and associations, we used astrometric catalogues with the
highest quality kinematic and photometric data currently available. Results: The presence of a magnetic field is confirmed in nine stars
previously observed with FORS 1/2: HD 36879, HD 47839, CPD-28 2561,
CPD-47 2963, HD 93843, HD 148937, HD 149757, HD 328856, and HD 164794.
New magnetic field detections at a significance level of at least
3σ were achieved in five stars: HD 92206c, HD 93521, HD 93632,
CPD-46 8221, and HD 157857. Among the stars with a detected magnetic
field, five stars belong to open clusters with high membership
probability. According to previous kinematic studies, five magnetic
O-type stars in our sample are candidate runaway stars.