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Characterization of the magnetic field of the Herbig Be star HD200775
- Source :
- Monthly Notices of the Royal Astronomical Society, Monthly Notices of the Royal Astronomical Society, Oxford University Press (OUP): Policy P-Oxford Open Option A, 2008, 385, pp.391-403. ⟨10.1111/J.1365-2966.2008.12842.X⟩, Monthly Notices of the Royal Astronomical Society, 2008, 385, pp.391-403. ⟨10.1111/J.1365-2966.2008.12842.X⟩
- Publication Year :
- 2008
- Publisher :
- HAL CCSD, 2008.
-
Abstract
- After our recent discovery of four magnetic Herbig stars, we have decided to study in detail one of them, HD 200775, to determine if its magnetic topology is similar to that of the main sequence magnetic stars. With this aim, we monitored this star in Stokes I and V over more than two years, using the new spectropolarimeters ESPaDOnS at CFHT, and Narval at TBL. Using our data, we find that HD 200775 is a double-lined spectroscopic binary system, whose secondary seems similar, in temperature, to the primary. We determine the luminosity ratio of the system, and using the luminosity of the system found in literature, we derive the luminosity of both stars. From our measurements of the radial velocities of both stars we determine the ephemeris and the orbital parameters of the system. We have fitted 30 Stokes V profiles simultaneously, using a chi2 minimisation method, with a decentered-dipole model. The best-fit model provides a rotation period of 4.3281 d an inclination angle of 60 degrees, and a magnetic obliquity angle of 125 degrees. The polar strength of the magnetic dipole field is 1000 G, which is decentered by 0.05 R* from the center of the star. The derived magnetic field model is qualitatively identical to those commonly observed in the Ap/Bp stars, which bring strong argument in favour of the fossil field hypothesis, to explain the origin of the magnetic fields in the main sequence Ap/Bp stars. Our determination of the inclination of the rotation axis leads to a radius of the primary which is smaller than that derived from the HR diagram position. This can be explained by a larger intrinsic luminosity of the secondary relative to the primary, due to a larger circumstellar extinction of the secondary relative to the primary.<br />Comment: Accepted for publication in MNRAS, 14 pages, 10 figures
- Subjects :
- [SDU.ASTR.HE]Sciences of the Universe [physics]/Astrophysics [astro-ph]/High Energy Astrophysical Phenomena [astro-ph.HE]
Astrophysics (astro-ph)
stars: individual: HD200775
FOS: Physical sciences
instrumentation: polarimeters
stars: pre-main-sequence
Astrophysics::Cosmology and Extragalactic Astrophysics
Astrophysics
[PHYS.ASTR.CO]Physics [physics]/Astrophysics [astro-ph]/Cosmology and Extra-Galactic Astrophysics [astro-ph.CO]
stars: magnetic fields
Astrophysics::Solar and Stellar Astrophysics
Astrophysics::Earth and Planetary Astrophysics
Astrophysics::Galaxy Astrophysics
binaries: spectroscopic
Subjects
Details
- Language :
- English
- ISSN :
- 00358711 and 13652966
- Database :
- OpenAIRE
- Journal :
- Monthly Notices of the Royal Astronomical Society, Monthly Notices of the Royal Astronomical Society, Oxford University Press (OUP): Policy P-Oxford Open Option A, 2008, 385, pp.391-403. ⟨10.1111/J.1365-2966.2008.12842.X⟩, Monthly Notices of the Royal Astronomical Society, 2008, 385, pp.391-403. ⟨10.1111/J.1365-2966.2008.12842.X⟩
- Accession number :
- edsair.doi.dedup.....d8d0463fb491c9346d66d6d56f7f0b81