One size does not fit all: Evidence for a range of mixing efficiencies in stellar evolution calculations

Johnston, C.

doi:10.1051/0004-6361/202141080

Cited by 44 publications

(34 citation statements)

References 92 publications

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“…In line with these results, Johnston (2021) recently compiled a list of known main-sequence convective core masses for 110 stars in the mass range 1.14-24 M e derived from asteroseismology or the modeling of eclipsing binaries, showing that the standard stellar evolution models without chemical mixing frequently underestimate the core masses of the stars. The results presented here are in full agreement with Johnston (2021), who considered a much broader range in mass.…”

Section: Estimating Final Helium Core Massessupporting

confidence: 90%

On the Diversity of Mixing and Helium Core Masses of B-type Dwarfs from Gravity-mode Asteroseismology

Pedersen

2022

ApJ

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The chemical evolution of the galaxy is largely guided by the yields from massive stars. Their evolution is heavily influenced by their internal mixing, allowing the stars to live longer and yield a more massive helium core at the end of their main-sequence evolution. Asteroseismology is a powerful tool for studying stellar interiors by providing direct probes of the interior physics of the oscillating stars. This work revisits the recently derived internal mixing profiles of 26 slowly pulsating B stars observed by the Kepler space telescope, in order to investigate how well the mixing profiles can in fact be distinguished from one another as well as provide predictions for the expected helium core masses obtained at the end of the main-sequence evolution. We find that for five of these stars the mixing profile is derived unambiguously, while the remaining stars have at least one other mixing profile which explains the oscillations equally well. Convective penetration is preferred over exponential diffusive overshoot for ≈55% of the stars, while stratified mixing is preferred in the envelope (≈39%). We estimate the expected helium core masses obtained at the end of the main-sequence evolution and find them to be highly influenced by the estimated amount of mixing occurring in the envelopes of the stars.

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Section: Estimating Final Helium Core Massessupporting

confidence: 90%

On the Diversity of Mixing and Helium Core Masses of B-type Dwarfs from Gravity-mode Asteroseismology

Pedersen

2022

ApJ

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“…Andersen et al 1990;Ribas et al 2000;Torres et al 2010). A prominent recent trend is the finding that the properties of high-mass EBs need stronger internal mixing processes than predicted by standard evolutionary models (Tkachenko et al 2020;Johnston 2021). Subsequent evolution of high-mass short-period binaries leads to a wide variety of exotic objects that are important for many areas of stellar astrophysics, such as X-ray binaries, supernovae and gammaray bursts (Podsiadlowski et al 2002(Podsiadlowski et al , 2004Belczynski et al 2020;Chrimes et al 2020).…”

Section: Introductionmentioning

confidence: 99%

High-mass pulsators in eclipsing binaries observed usingTESS

Southworth

Bowman

2022

Monthly Notices of the Royal Astronomical Society

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Pulsations and binarity are both common features of massive stars. The study of pulsating massive stars in eclipsing binary systems hold great potential for constraining stellar structure and evolution theory. However, prior to the all-sky Transiting Exoplanet Survey Satellite (TESS) mission, few such systems had been discovered or studied in detail. We have inspected the TESS light curves of a large number of eclipsing binaries known to contain high-mass stars, and compiled a list of 18 objects which show intrinsic variability. The light curves were modelled both to determine the physical properties of the systems, and to remove the effects of binarity in order to leave residual light curves suitable for asteroseismic analysis. Precise mass and radius measurements were obtained for δ Cir, CC Cas, SZ Cam V436 Per and V539 Ara. We searched the residual light curves for pulsation signatures and, within our sample of 18 objects, we find six definite and eight possible cases of β Cephei pulsation, seven cases of stochastic low-frequency (SLF) variability, and eight instances of possible slowly pulsating B (SPB) star pulsation. The large number of pulsating eclipsing systems we have identified makes asteroseismology of high-mass stars in eclipsing binaries a feasible avenue to constrain the interior physics of a large sample of massive stars for the first time.

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“…Martins & Palacios 2013 for a comparison of different evolution codes). For massive stars, the lack of direct observational constraints produce fractional uncertainties for main-sequence lifetimes and helium core masses as much as 50% (Bowman 2020;Johnston 2021), which influences the nature of the compact object left behind (Langer 2012;Farrell et al 2020).…”

Section: Introductionmentioning

confidence: 99%

The CubeSpec space mission

Bowman¹,

Vandenbussche²,

Sana³

et al. 2022

A&A

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Context. There is currently a niche for providing high-cadence, high resolution, time-series optical spectroscopy from space, which can be filled by using a low-cost cubesat mission. The Belgian-led ESA/KU Leuven CubeSpec mission is specifically designed to provide space-based, low-cost spectroscopy with specific capabilities that can be optimised for a particular science need. Approved as an ESA in-orbit demonstrator, the CubeSpec satellite’s primary science objective will be to focus on obtaining high-cadence, high resolution optical spectroscopic data to facilitate asteroseismology of pulsating massive stars. Aims. In this first paper, we aim to search for pulsating massive stars suitable for the CubeSpec mission, specifically β Cep stars, which typically require time-series spectroscopy to identify the geometry of their pulsation modes. Methods. Based on the science requirements needed to enable asteroseismology of massive stars with the capabilities of CubeSpec’s spectrograph, we combined a literature study for pulsation with the analysis of recent high-cadence time-series photometry from the Transiting Exoplanet Survey Satellite (TESS) mission to classify the variability for stars brighter than V ≤ 4 mag and between O9 and B3 in spectral type. Results. Among the 90 stars that meet our magnitude and spectral type requirements, we identified 23 promising β Cep stars with high-amplitude (non-)radial pulsation modes with frequencies below 7 d−1. Using further constraints on projected rotational velocities, pulsation amplitudes, and the number of pulsation modes, we devised a prioritised target list for the CubeSpec mission according to its science requirements and the potential of the targets for asteroseismology. The full target catalogue further provides a modern TESS-based review of line profile and photometric variability properties among bright O9–B3 stars.

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One size does not fit all: Evidence for a range of mixing efficiencies in stellar evolution calculations

Cited by 44 publications

References 92 publications

On the Diversity of Mixing and Helium Core Masses of B-type Dwarfs from Gravity-mode Asteroseismology

On the Diversity of Mixing and Helium Core Masses of B-type Dwarfs from Gravity-mode Asteroseismology

High-mass pulsators in eclipsing binaries observed usingTESS

The CubeSpec space mission

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