Fossati, L.; Castro, N.; Morel, T.; Langer, N.; Briquet, M.; Carroll, T. A.; Hubrig, S.; Nieva, M. F.; Oskinova, L. M.; Przybilla, N.; Schneider, F. R. N.; Schöller, M.; Simón-Díaz, S.; Ilyin, I.; de Koter, A.; Reisenegger, A.; Sana, H.
Referencia bibliográfica
Astronomy and Astrophysics, Volume 574, id.A20, 15 pp.
Fecha de publicación:
2
2015
Revista
Número de citas
67
Número de citas referidas
52
Descripción
Only a small fraction of massive stars seem to host a measurable
structured magnetic field, whose origin is still unknown and whose
implications for stellar evolution still need to be assessed. Within the
context of the "B fields in OB stars (BOB)" collaboration, we used the
HARPSpol spectropolarimeter to observe the early B-type stars β CMa
(HD 44743; B1 II/III) and ɛ CMa (HD 52089; B1.5II) in December
2013 and April 2014. For both stars, we consistently detected the
signature of a weak (<30 G in absolute value) longitudinal magnetic
field, approximately constant with time. We determined the physical
parameters of both stars and characterise their X-ray spectrum. For the
β Cep star β CMa, our mode identification analysis led to
determining a rotation period of 13.6 ± 1.2 days and of an
inclination angle of the rotation axis of 57.6 ± 1.7°, with
respect to the line of sight. On the basis of these measurements and
assuming a dipolar field geometry, we derived a best fitting obliquity
of about 22° and a dipolar magnetic field strength (Bd)
of about 100 G (60
Proyectos relacionados
Proyecto IACOB: Una Nueva Era en el Estudio de Estrellas OB Galácticas
Massive stars has been many times claimed as Cosmic Engines and Gifts of Nature for the study of the Universe, from the Solar neighbourhood to the large-z Universe. The complete understanding of the physical properties and evolution of massive stars (and their interplay with the ISM) is crucial for many fields of Astrophysics and, ultimately, to
Sergio
Simón Díaz