Detection of magnetic fields in He-rich early B-type stars using HARPSpol
| Autor: | Markus Schöller, I. V. Ilyin, Silva P. Järvinen, Norberto Castro, Swetlana Hubrig, Norbert Przybilla, M.-F. Nieva |
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| Rok vydání: | 2018 |
| Předmět: |
Physics
010308 nuclear & particles physics Polarimetry FOS: Physical sciences chemistry.chemical_element Astronomy and Astrophysics Astrophysics 01 natural sciences Spectral line law.invention Magnetic field Telescope Radial velocity Stars Astrophysics - Solar and Stellar Astrophysics chemistry Space and Planetary Science law Planet 0103 physical sciences Astrophysics::Solar and Stellar Astrophysics Astrophysics::Earth and Planetary Astrophysics 010303 astronomy & astrophysics Solar and Stellar Astrophysics (astro-ph.SR) Helium |
| Zdroj: | Astronomy & Astrophysics. 618:L2 |
| ISSN: | 1432-0746 0004-6361 |
| DOI: | 10.1051/0004-6361/201833171 |
| Popis: | We focus on early-B type stars with helium overabundance, for which the presence of a magnetic field has not previously been reported. The measurements were carried out using high-spectral-resolution spectropolarimetric observations obtained with the High Accuracy Radial velocity Planet Searcher (HARPS) in polarimetric mode, installed at the ESO La Silla 3.6m telescope. For five He-rich stars, the longitudinal magnetic field was detected for the first time. For one target, HD58260, the presence of a longitudinal magnetic field of the order of 1.8 kG has already been reported in the literature, but the magnetic field has remained constant over tens of years. Our measurement carried out using the polarimetric spectra obtained in 2015 March indicates a slight decrease of the longitudinal magnetic field strength compared to measurements reported in previous works. A search for periodic modulation in available photometric data allowed us to confidently establish a period of 2.64119$\pm$0.00420 d in archival ASAS3 data for CPD -27$^{\circ}$ 1791. No period could be determined for the other five stars. The obtained results support the scenario that all He-rich stars are detectably magnetic and form an extension of the Ap star phenomenon to higher temperatures. Comment: Accepted as A&A Letter |
| Databáze: | OpenAIRE |
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