TY  - GEN
A1  - Morel, T.
A1  - Castro, Norberto
A1  - Fossati, Luca
A1  - Hubrig, Swetlana
A1  - Langer, N.
A1  - Przybilla, Norbert
A1  - Schöller, Markus
A1  - Carroll, Thorsten Anthony
A1  - Ilyin, Ilya
A1  - Irrgang, Andreas
A1  - Oskinova, Lida
A1  - Schneider, Fabian R. N.
A1  - Simon Díaz, Sergio
A1  - Briquet, Maryline
A1  - González, Jean-Francois
A1  - Kharchenko, Nina
A1  - Nieva, M.-F.
A1  - Scholz, Ralf-Dieter
A1  - de Koter, Alexander
A1  - Hamann, Wolf-Rainer
A1  - Herrero, Artemio
A1  - Maíz Apellániz, Jesus
A1  - Sana, Hugues
A1  - Arlt, Rainer
A1  - Barbá, Rodolfo H.
A1  - Dufton, Polly
A1  - Kholtygin, Alexander
A1  - Mathys, Gautier
A1  - Piskunov, Anatoly E.
A1  - Reisenegger, Andreas
A1  - Spruit, H.
A1  - Yoon, S.-C.
T1  - The B fields in OB stars (BOB) survey
T2  - Postprints der Universität Potsdam : Mathematisch-Naturwissenschaftliche Reihe
N2  - The B fields in OB stars (BOB) survey is an ESO large programme collecting spectropolarimetric observations for a large number of early-type stars in order to study the occurrence rate, properties, and ultimately the origin of magnetic fields in massive stars. As of July 2014, a total of 98 objects were observed over 20 nights with FORS2 and HARPSpol. Our preliminary results indicate that the fraction of magnetic OB stars with an organised, detectable field is low. This conclusion, now independently reached by two different surveys, has profound implications for any theoretical model attempting to explain the field formation in these objects. We discuss in this contribution some important issues addressed by our observations (e.g., the lower bound of the field strength) and the discovery of some remarkable objects.
T3  - Zweitveröffentlichungen der Universität Potsdam : Mathematisch-Naturwissenschaftliche Reihe - 821 
KW  - magnetic fields
KW  - stars: early-type
KW  - stars: magnetic fields
KW  - stars: individual (HD 164492C, CPD –57 ◦ 3509, HD 54879, β CMa, ε CMa)
Y1  - 2020
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus4-415238
SN  - 1866-8372
IS  - 821
ER  - 
TY  - JOUR
A1  - Hubrig, Swetlana
A1  - Fossati, Luca
A1  - Carroll, Thorsten Anthony
A1  - Castro, Norberto
A1  - Gonzalez, J. F.
A1  - Ilyin, Ilya
A1  - Przybilla, Norbert
A1  - Schoeller, M.
A1  - Oskinova, Lida
A1  - Morel, T.
A1  - Langer, N.
A1  - Scholz, Ralf-Dieter
A1  - Kharchenko, N. V.
A1  - Nieva, M. -F.
T1  - B fields in OB stars (BOB): The discovery of a magnetic field in a multiple system in the Trifid nebula, one of the youngest star forming regions
JF  - Astronomy and astrophysics : an international weekly journal
N2  - Aims. Recent magnetic field surveys in O- and B-type stars revealed that about 10% of the core-hydrogen-burning massive stars host large-scale magnetic fields. The physical origin of these fields is highly debated. To identify and model the physical processes responsible for the generation of magnetic fields in massive stars, it is important to establish whether magnetic massive stars are found in very young star-forming regions or whether they are formed in close interacting binary systems.
 Methods. In the framework of our ESO Large Program, we carried out low-resolution spectropolarimetric observations with FORS 2 in 2013 April of the three most massive central stars in the Trifid nebula, HD 164492A, HD 164492C, and HD 164492D. These observations indicated a strong longitudinal magnetic field of about 500-600 G in the poorly studied component HD 164492C. To confirm this detection, we used HARPS in spectropolarimetric mode on two consecutive nights in 2013 June.
 Results. Our HARPS observations confirmed the longitudinal magnetic field in HD 164492C. Furthermore, the HARPS observations revealed that HD 164492C cannot be considered as a single star as it possesses one or two companions. The spectral appearance indicates that the primary is most likely of spectral type B1-B1.5 V. Since in both observing nights most spectral lines appear blended, it is currently unclear which components are magnetic. Long-term monitoring using high-resolution spectropolarimetry is necessary to separate the contribution of each component to the magnetic signal. Given the location of the system HD 164492C in one of the youngest star formation regions, this system can be considered as a Rosetta Stone for our understanding of the origin of magnetic fields in massive stars.
KW  - binaries: close
KW  - stars: early-type
KW  - stars: fundamental parameters
KW  - stars: magnetic field
KW  - stars: variables: general
KW  - stars: individual: HD 164492C
Y1  - 2014
U6  - https://doi.org/10.1051/0004-6361/201423490
SN  - 0004-6361
SN  - 1432-0746
VL  - 564
PB  - EDP Sciences
CY  - Les Ulis
ER  -