Combined asteroseismology, spectroscopy, and astrometry of the CoRoT B2V target HD 170580

Abstract

Space asteroseismology reveals that stellar structure and evolution models of intermediate- and high-mass stars are in need of improvement in terms of angular momentum and chemical element transport. We aim to probe the interior structure of a hot massive star in the core-hydrogen burning phase of its evolution. We analyse CoRoT space photometry, Gaia DR2 space astrometry, and high-resolution high signal-to-noise HERMES and HARPS time-series spectroscopy of the slowly rotating B2V star HD 170580. From the time-series spectroscopy we derive $vsini=4\pm 2$km\,s${}^{-1}$, where the uncertainty results from the complex pulsational line-profile variability. We detect 42 frequencies with amplitude above 5$\sigma$. Among these we identify 5 rotationally split triplets and 1 quintuplet. Asteroseismic modelling based on CoRoT, Gaia DR2 and spectroscopic data leads to a star of 8M${}_{\odot }$ near core-hydrogen exhaustion and an extended overshoot zone. The detected low-order pressure-mode frequencies cannot be fit within the uncertainties of the CoRoT data by models without atomic diffusion. Irrespective of this limitation, the low-order gravity modes reveal HD 170580 to be a slow rotator with an average rotation period between 73 and 98 d and a hint of small differential rotation. Future Gaia DR3 data taking into account the multiplicity of the star, along with long-term TESS photometry would allow to put better observational constraints on the asteroseismic models of this blue evolved massive star. Improved modelling with atomic diffusion, including radiative levitation, is needed to achieve compliance with the low helium surface abundance of the star. This poses immense computational challenges but is required to derive the interior rotation and mixing profiles of this star.

Manuscript accepted for publication in Astronomy & Astrophysics; 13 pages, 8 figures, 2 tables

References in corpus (10)

• The interior rotation of a sample of gamma Doradus stars from ensemble modelling of their gravity mode period spacings
• Signatures of internal rotation discovered in the Kepler data of five slowly pulsating B stars
• A unifying explanation of complex frequency spectra of gamma Dor, SPB and Be stars: combination frequencies and highly non-sinusoidal light curves
• Gravito-inertial and pressure modes detected in the B3 IV CoRoT target HD 43317
• A detection threshold in the amplitude spectra calculated from Kepler data obtained during K2 mission
• On the Chemical Mixing Induced by Internal Gravity Waves (IGW)
• KIC 10526294: a slowly rotating B star with rotationally split, quasi-equally spaced gravity modes
• Projected Rotational Velocities and Stellar Characterization of 350 B Stars in the Nearby Galactic Disk
• Magnetic characterization of the SPB/$\beta$ Cep hybrid pulsator HD 43317
• The SpaceInn-SISMA database: characterization of a large sample of variable and active stars by means of HARPS spectra

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