J/A+A/411/565 Magnetic field in V2052 Oph (Neiner+, 2003)
Rotation, pulsations and magnetic field in V2052 Ophiuchi: a new He-strong star.
Neiner C., Henrichs H.F., Floquet M., Fremat Y., Preuss O., Hubert A.M.,
Geers V.C., Tijani A.H., Nichols J., Jankov S.
<Astron. Astrophys. 411, 565 (2003)>
=2003A&A...411..565N 2003A&A...411..565N
ADC_Keywords: Stars, variable ; Magnetic fields
Keywords: stars: magnetic fields - stars: winds, outflows -
stars: chemically peculiar - stars: early-type - stars: oscillations
Abstract:
V2052 Oph is a β Cep star with vsini∼60km/s. The behavior of its
stellar wind was studied in the ultraviolet wavelength region with the
IUE satellite. It revealed periodic variations in the equivalent
widths (EW) of the resonance lines of wind-sensitive ions with a
period of 3.638833d, which is identified as the rotational period.
These variations are typical of magnetic stars. Therefore
time-resolved circular spectropolarimetric observations were obtained
with the Musicos echelle spectropolarimeter at the 2-m Telescope
Bernard Lyot (TBL) to search for a magnetic field in the star. Stokes
V patterns were observed, the inclination and magnetic angles were
derived and a value was determined for the polar magnetic field
(250±190G) using an oblique rotator dipole model. The spectroscopic
information was used to search for periodicity in line-profile
variations (lpv), radial velocity and minimum intensity curves.
Multiperiodicity was found, corresponding to radial (f1=7.15c/d) and
non-radial (f2=6.82c/d, l=3 or 4) pulsation modes. The rotation period
is also detected in rotationally modulated observables because of the
magnetic poles passing through the observer's line of sight. We
determined the stellar parameters of the star, which was found to be
chemically peculiar, in particular He-enriched. This makes V2052 Oph
the first magnetic He-strong early B star with known pulsational
properties.
Objects:
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RA (2000) DE Designation(s)
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17 56 18.4 +00 40 13 V2052 Oph = HD 163472
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File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table7.dat 44 112 Longitudinal magnetic field measurements
table7.tex 168 58 LaTeX version of table 7
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See also:
II/134 : Catalog of Magnetic Field Measurements (Didelon 1983)
J/A+A/409/275 : Rotation and magnetic field in omega Ori (Neiner+, 2003)
Byte-by-byte Description of file: table7.dat
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Bytes Format Units Label Explanations
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1- 3 I3 --- Seq Sequential number of the measurement
5- 10 F6.2 d HJD Heliocentric Julian date of measurement
13- 17 F5.3 --- Phase [0,1[ Phase (with P = 3.638833 d)
19- 22 I4 10-4T B Longitudinal field measurement
25- 27 I3 10-4T e_B rms uncertainty on B
29- 34 F6.1 10-4T N Null polarisation (1)
36- 38 I3 10-4T e_N rms uncertainty on N
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Note (1): The null polarisation gives an indication of the pollution by
non-stellar effects and should be zero for a perfect measurement.
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Acknowledgements: Coralie Neiner
(End) Patricia Bauer [CDS] 18-Sep-2003