TY  - JOUR
A1  - Dominis, Dijana
A1  - Butler, Keith
A1  - Simon, Klaus
A1  - Clausen, Jens Viggo
A1  - Pritchard, John
T1  - Magellanic clouds' binaries as distance indicators
Y1  - 2001
SN  - 0934-4438
ER  - 
TY  - JOUR
A1  - Przybilla, Norbert
A1  - Fossati, Luca
A1  - Hubrig, Swetlana
A1  - Nieva, M. -F.
A1  - Jaervinen, S. P.
A1  - Castro, Norberto
A1  - Schoeller, M.
A1  - Ilyin, Ilya
A1  - Butler, Keith
A1  - Schneider, F. R. N.
A1  - Oskinova, Lida
A1  - Morel, T.
A1  - Langer, N.
A1  - de Koter, A.
T1  - B fields in OB stars (BOB): Detection of a magnetic field in the He-strong star CPD-57 degrees 3509
JF  - Organic letters
N2  - Methods. Spectropolarimetric observations with FORS2 and HARPSpol are analysed using two independent approaches to quantify the magnetic field strength. A high-S/N FLAMES/GIRAFFE spectrum is analysed using a hybrid non-LTE model atmosphere technique. Comparison with stellar evolution models constrains the fundamental parameters of the star. Results. We obtain a firm detection of a surface averaged longitudinal magnetic field with a maximum amplitude of about 1 kG. Assuming a dipolar configuration of the magnetic field, this implies a dipolar field strength larger than 3.3 kG. Moreover, the large amplitude and fast variation (within about 1 day) of the longitudinal magnetic field implies that CPD-57 degrees 3509 is spinning very fast despite its apparently slow projected rotational velocity. The star should be able to support a centrifugal magnetosphere, yet the spectrum shows no sign of magnetically confined material; in particular, emission in H alpha is not observed. Apparently, the wind is either not strong enough for enough material to accumulate in the magnetosphere to become observable or, alternatively, some leakage process leads to loss of material from the magnetosphere. The quantitative spectroscopic analysis of the star yields an effective temperature and a logarithmic surface gravity of 23 750 +/- 250 K and 4.05 +/- 0.10, respectively, and a surface helium fraction of 0.28 +/- 0.02 by number. The surface abundances of C, N, O, Ne, S, and Ar are compatible with the cosmic abundance standard, whereas Mg, Al, Si, and Fe are depleted by about a factor of 2. This abundance pattern can be understood as the consequence of a fractionated stellar wind. CPD-57 degrees 3509 is one of the most evolved He-strong stars known with an independent age constraint due to its cluster membership.
KW  - stars: abundances
KW  - stars: atmospheres
KW  - stars: evolution
KW  - stars: magnetic field
KW  - stars: individual: CPD-57 degrees 3509
KW  - stars: massive
Y1  - 2016
U6  - https://doi.org/10.1051/0004-6361/201527646
SN  - 1432-0746
VL  - 587
PB  - EDP Sciences
CY  - Les Ulis
ER  -