ICATE   21876
INSTITUTO DE CIENCIAS ASTRONOMICAS, DE LA TIERRA Y DEL ESPACIO
Unidad Ejecutora - UE
artículos
Título:
Magnetic field detection in the bright A0-type supergiant HD 92207
Autor/es:
HUBRIG, S.; SCHÖLLER, M.; KHOLTYGIN, A. F.; GONZÁLEZ, J.F.; KHARCHENKO, N. V.; STEFFEN, M.
Revista:
ASTRONOMY AND ASTROPHYSICS
Editorial:
EDP SCIENCES S A
Referencias:
Lugar: Paris; Año: 2012 vol. 546 p. 1 - 4
ISSN:
0004-6361
Resumen:
Context. Recent developments in observational techniques and theories
revealed the potential significance of magnetic fields for stellar
structure, evolution, and circumstellar environment. At present, the
distribution of magnetic field strengths in massive stars from the
zero-age main sequence to more evolved stages, which would shed light on
the origin of the magnetic field, has not been studied. Aims: We
searched for the presence of a magnetic field in the visually brightest
early A-type supergiant HD 92207. Methods: Observations were
obtained using the low-resolution spectropolarimetric mode of FORS 2
(FOcal Reducer low dispersion Spectrograph) mounted on the 8 m Antu
telescope of the VLT. For the mean longitudinal magnetic field
measurements, we applied a linear regression analysis in two ways: using
only the absorption hydrogen Balmer lines or using the entire spectrum
including all available absorption lines. Results: A mean
longitudinal magnetic field at a significance level of more than
3σ was detected in two out of three observations distributed over
about one year. It is one of the rare cases where a field of about a few
hundred Gauss is detected in an early A-type supergiant. All line
profiles in the spectra of HD 92207 undergo distinct variations in
radial velocities and intensities, probably caused by previously
detected non-radial pulsations.