Reference : Detecting and modelling the magnetic field of the β Cephei star V 2052 Ophiuchi
Scientific journals : Article
Physical, chemical, mathematical & earth Sciences : Space science, astronomy & astrophysics
http://hdl.handle.net/2268/110790
Detecting and modelling the magnetic field of the β Cephei star V 2052 Ophiuchi
English
Neiner, C. [LESIA, Observatoire de Paris, CNRS UMR 8109, UPMC, Université Paris Diderot, 5 place Jules Janssen, 92190, Meudon, France]
Alecian, E. [LESIA, Observatoire de Paris, CNRS UMR 8109, UPMC, Université Paris Diderot, 5 place Jules Janssen, 92190, Meudon, France]
Briquet, Maryline mailto [Université de Liège - ULg > Département d'astrophys., géophysique et océanographie (AGO) > Astrophysique stellaire théorique et astérosismologie]
Floquet, M. [GEPI, Observatoire de Paris, CNRS UMR 8111, Université Paris Diderot, 5 place Jules Janssen, 92190, Meudon, France]
Frémat, Y. [Royal Observatory of Belgium, 3 avenue circulaire, 1180, Brussels, Belgium]
Martayan, C. [ESO, Alonso de Cordova 3107, Vitacura, Casilla 19001, Santiago 19, Chile]
Thizy, O. [Shelyak Instruments, Les Roussets, 38420, Revel, France]
1-Jan-2012
Astronomy and Astrophysics
EDP Sciences
537
148
Yes (verified by ORBi)
International
0004-6361
1432-0746
Les Ulis
France
[en] stars: magnetic field ; stars: early-type ; stars: individual: V 2052 Oph ; starspots
[en] <BR /> Aims: Following the indirect detection of a magnetic field in the β Cephei star <ASTROBJ>V 2052 Oph</ASTROBJ> by Neiner and collaborators in 2003 with the Musicos spectropolarimeter, we remeasured the magnetic field of this star to attempt to directly confirm the detection of a magnetic field and study its configuration in greater detail. <BR /> Methods: We used the Narval spectropolarimeter installed at TBL (Pic du Midi, France), which is about 20 times more efficient than the Musicos spectropolarimeter. We applied the least-squares deconvolution (LSD) technique to various groups of lines to measure the circular polarisation of the light coming from <ASTROBJ>V 2052 Oph</ASTROBJ>. We synthesized the measured Stokes V profiles with a centred and off-centred dipole model. <BR /> Results: For the first time, we clearly detect the Zeeman signature in the Stokes V profiles of <ASTROBJ>V 2052 Oph</ASTROBJ> and thus directly prove the presence of a magnetic field in this star. The modulation with the rotation period is also confirmed and reflects an oblique dipole field. Thanks to the small error bars on the measurements, we are able to study the behaviour of different groups of lines and the centring of the dipole in the star. We find that the dipole is most likely off-centred along the magnetic axis and that He spots are present at the surface next to the magnetic axis. <BR /> Conclusions: We conclude that <ASTROBJ>V 2052 Oph</ASTROBJ> is a magnetic He-strong β Cep star, with a dipole field, probably off-centred, with B[SUB]pol[/SUB] ~ 400 G and He patches close to the magnetic poles. Based on observations obtained with the Narval spectropolarimeter at the Télescope Bernard Lyot, Observatoire du Pic du Midi, France.
http://hdl.handle.net/2268/110790
10.1051/0004-6361/201117941
http://esoads.eso.org/abs/2012A%26A...537A.148N

File(s) associated to this reference

Fulltext file(s):

FileCommentaryVersionSizeAccess
Open access
aa17941-11.pdfPublisher postprint1.07 MBView/Open

Bookmark and Share SFX Query

All documents in ORBi are protected by a user license.