Polarimetric detection of non-radial oscillation modes in the β Cephei star β Crucis

Autor: Daniel V. Cotton, Derek L. Buzasi, Conny Aerts, Jeremy Bailey, Siemen Burssens, May G. Pedersen, Dennis Stello, Lucyna Kedziora-Chudczer, Ain De Horta, Peter De Cat, Fiona Lewis, Sai Prathyusha Malla, Duncan J. Wright, Kimberly Bott
Rok vydání: 2022
Předmět:
Zdroj: Nature Astronomy, 6, pp. 154-164
Nature Astronomy, 6, 154-164
ISSN: 2397-3366
DOI: 10.1038/s41550-021-01531-9
Popis: Here we report the detection of polarization variations due to nonradial modes in the beta Cephei star beta Crucis. In so doing we confirm 40-year-old predictions of pulsation-induced polarization variability and its utility in asteroseismology for mode identification. In an approach suited to other beta Cep stars, we combine polarimetry with space-based photometry and archival spectroscopy to identify the dominant nonradial mode in polarimetry, f2, as l = 3, m = -3 (in the m-convention of Dziembowski) and determine the stellar axis position angle as 25 (or 205) +/- 8 deg. The rotation axis inclination to the line of sight was derived as approx. 46 deg. from combined polarimetry and spectroscopy, facilitating identification of additional modes and allowing for asteroseismic modelling. This reveals a star of 14.5 +/- 0.5 Solar masses and a convective core containing approx. 28% of its mass -- making beta Crucis the most massive star with an asteroseismic age.
Comment: 33 pages, 11 figures, 8 tables (incl. Supplementary Information). Accepted version; published as Cotton et al. (2022), Nature Astro., Vol 6, pp 154-164. Data is available through VizieR as: J/other/NatAs/6.154. Two explainer articles are available: Cotton & Buzasi (2022), Nature Astro., Vol 6, pp 24-25; Baade (2022), Nature Astro., Vol 6, pp 20-21
Databáze: OpenAIRE
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