Characterizing the magnetic field and spectral variability of the rigidly rotating magnetosphere star HD345439

Abstract

A team involved in APOGEE, one of the Sloan Digital Sky Survey III programs, recently announced the discovery of two rare rigidly rotating magnetosphere stars, HD345439 and HD23478. Near-infrared spectra of these objects revealed emission-line behavior identical to that previously discovered in the helium-strong star sigma Ori E, which has a strong magnetic field and rotates fast. A single spectropolarimetric observation of HD345439 with FORS2 at the VLT in 2014 over 88min indicated that HD345439 may host a strong, rapidly varying magnetic field. In this work, we present the results of our spectropolarimetric monitoring of this star with FORS2, which revealed the presence of a strong longitudinal magnetic field dominated by a dipolar component. The analysis of spectral variability indicates an opposite behaviour of He and Si lines, which is usually attributed to differences in the distribution of surface He and Si abundance spots.

5 pages, 1 table, 6 figures, accepted for publication in MNRAS. arXiv admin note: text overlap with arXiv:1702.01063

References in corpus (6)

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• Discovery of Two Rare Rigidly-Rotating Magnetosphere Stars in the APOGEE Survey
• B fields in OB stars (BOB): FORS2 spectropolarimetric follow-up of the two rare rigidly rotating magnetosphere stars HD23478 and HD345439
• An infrared diagnostic for magnetism in hot stars
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• Trumpler 16-26: A New Centrifugal Magnetosphere Discovered via SDSS/APOGEE H-band Spectroscopy
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