Bibcode
Fossati, L.; Castro, N.; Schöller, M.; Hubrig, S.; Langer, N.; Morel, T.; Briquet, M.; Herrero, A.; Przybilla, N.; Sana, H.; Schneider, F. R. N.; de Koter, A.; BOB Collaboration
Referencia bibliográfica
Astronomy and Astrophysics, Volume 582, id.A45, 19 pp.
Advertised on:
10
2015
Revista
Número de citas
94
Número de citas referidas
81
Descripción
Within the context of the collaboration "B fields in OB stars" (BOB), we
used the FORS2 low-resolution spectropolarimeter to search for a
magnetic field in 50 massive stars, including two reference magnetic
massive stars. Because of the many controversies of magnetic field
detections obtained with the FORS instruments, we derived the magnetic
field values with two completely independent reduction and analysis
pipelines. We compare and discuss the results obtained from the two
pipelines. We obtained a general good agreement, indicating that most of
the discrepancies on magnetic field detections reported in the
literature are caused by the interpretation of the significance of the
results (i.e., 3-4σ detections considered as genuine, or not),
instead of by significant differences in the derived magnetic field
values. By combining our results with past FORS1 measurements of HD
46328, we improve the estimate of the stellar rotation period, obtaining
P = 2.17950 ± 0.00009 days. For HD 125823, our FORS2 measurements
do not fit the available magnetic field model, based on magnetic field
values obtained 30 years ago. We repeatedly detect a magnetic field for
the O9.7V star HD 54879, the HD 164492C massive binary, and the He-rich
star CPD -57 3509. We obtain a magnetic field detection rate of 6
± 4%, while by considering only the apparently slow rotators we
derive a detection rate of 8 ± 5%, both comparable with what was
previously reported by other similar surveys. We are left with the
intriguing result that, although the large majority of magnetic massive
stars is rotating slowly, our detection rate is not a strong function of
the stellar rotational velocity.
Based on observations made with ESO Telescopes at the La Silla Paranal
Observatory under programme ID 191.D-0255(A, C).