First Observation of the Complete Rotation Period of the Ultra-Slowly Rotating Magnetic O Star HD 54879

Fuente: arXiv
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Main Authors: Erba, C., Folsom, C. P., David-Uraz, A., Wade, G. A., Seadrow, S., Bellotti, S., Fossati, L., Petit, V., Shultz, M. E.
Format: Preprint
Published: 2024
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author Erba, C.
Folsom, C. P.
David-Uraz, A.
Wade, G. A.
Seadrow, S.
Bellotti, S.
Fossati, L.
Petit, V.
Shultz, M. E.
author_facet Erba, C.
Folsom, C. P.
David-Uraz, A.
Wade, G. A.
Seadrow, S.
Bellotti, S.
Fossati, L.
Petit, V.
Shultz, M. E.
contents HD 54879 is the most recently discovered magnetic O-type star. Previous studies ruled out a rotation period shorter than 7 years, implying that HD 54879 is the second most slowly-rotating known magnetic O-type star. We report new high-resolution spectropolarimetric measurements of HD 54879, which confirm that a full stellar rotation cycle has been observed. We derive a stellar rotation period from the longitudinal magnetic field measurements of P = 2562+63-58 d (about 7.02 yr). The radial velocity of HD 54879 has been stable over the last decade of observations. We explore equivalent widths and longitudinal magnetic fields calculated from lines of different elements, and conclude the atmosphere of HD 54879 is likely chemically homogeneous, with no strong evidence for chemical stratification or lateral abundance nonuniformities. We present the first detailed magnetic map of the star, with an average surface magnetic field strength of 2954 G, and a strength for the dipole component of 3939 G. There is a significant amount of magnetic energy in the quadrupole components of the field (23%). Thus, we find HD 54879 has a strong magnetic field with a significantly complex topology.
format Preprint
id arxiv_https___arxiv_org_abs_2401_09722
institution arXiv
publishDate 2024
record_format arxiv
spellingShingle First Observation of the Complete Rotation Period of the Ultra-Slowly Rotating Magnetic O Star HD 54879
Erba, C.
Folsom, C. P.
David-Uraz, A.
Wade, G. A.
Seadrow, S.
Bellotti, S.
Fossati, L.
Petit, V.
Shultz, M. E.
Solar and Stellar Astrophysics
HD 54879 is the most recently discovered magnetic O-type star. Previous studies ruled out a rotation period shorter than 7 years, implying that HD 54879 is the second most slowly-rotating known magnetic O-type star. We report new high-resolution spectropolarimetric measurements of HD 54879, which confirm that a full stellar rotation cycle has been observed. We derive a stellar rotation period from the longitudinal magnetic field measurements of P = 2562+63-58 d (about 7.02 yr). The radial velocity of HD 54879 has been stable over the last decade of observations. We explore equivalent widths and longitudinal magnetic fields calculated from lines of different elements, and conclude the atmosphere of HD 54879 is likely chemically homogeneous, with no strong evidence for chemical stratification or lateral abundance nonuniformities. We present the first detailed magnetic map of the star, with an average surface magnetic field strength of 2954 G, and a strength for the dipole component of 3939 G. There is a significant amount of magnetic energy in the quadrupole components of the field (23%). Thus, we find HD 54879 has a strong magnetic field with a significantly complex topology.
title First Observation of the Complete Rotation Period of the Ultra-Slowly Rotating Magnetic O Star HD 54879
topic Solar and Stellar Astrophysics
url https://arxiv.org/abs/2401.09722