A rival for Babcock's star: the extreme 30-kG variable magnetic field in the Ap star HD 75049
Autor: | Gautier Mathys, V. G. Elkin, L. M. Freyhammer, Swetlana Hubrig, D. W. Kurtz |
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Rok vydání: | 2010 |
Předmět: |
Physics
Rotation period Field (physics) F300 FOS: Physical sciences Astronomy and Astrophysics Astrophysics::Cosmology and Extragalactic Astrophysics Radius Astrophysics Star (graph theory) Magnetic field Astrophysics - Solar and Stellar Astrophysics Space and Planetary Science Beta (plasma physics) Astrophysics::Solar and Stellar Astrophysics Polar Astrophysics::Earth and Planetary Astrophysics Solar and Stellar Astrophysics (astro-ph.SR) Astrophysics::Galaxy Astrophysics Main sequence |
Zdroj: | Monthly Notices of the Royal Astronomical Society. 402:1883-1891 |
ISSN: | 1365-2966 0035-8711 |
Popis: | The extraordinary magnetic Ap star HD 75049 has been studied with data obtained with the European Southern Observatory Very Large Telescope and 2.2-m telescopes. Direct measurements reveal that the magnetic field modulus at maximum reaches 30 kG. The star shows photometric, spectral and magnetic variability with a rotation period of 4.049 d. Variations of the mean longitudinal magnetic field can be described to first order by a centred dipole model with an inclination i= 25°, an obliquity β= 60° and a polar field Bp= 42 kG. The combination of the longitudinal and surface magnetic field measurements implies a radius of R= 1.7 R⊙, suggesting that the star is close to the zero-age main sequence. HD 75049 displays moderate overabundances of Si, Ti, Cr, Fe and large overabundances of rare earth elements. This star has the second strongest magnetic field of any main-sequence star after Babcock's star, HD 215441, which it rivals. |
Databáze: | OpenAIRE |
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