Further critical tests of stellar evolution by means of double-lined eclipsing binaries

Pols, O. R.; Tout, Christopher A.; Schröder, K.-P.; Eggleton, P. P.; Manners, James

doi:10.1093/mnras/289.4.869

Cited by 225 publications

(234 citation statements)

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“…Additionally, the rotational transport itself may have been strengthened by the stellar coupling in the binary system (see e.g. de Mink et al 2009;Pols et al 1997). Unfortunately binary stellar models which treat the effect of mixing on the nucleosynthesis of lowmass stars are not yet available, but we can use single rotating AGB models to infer the impact of mixing during the pre-AGB phase on the surface chemical composition.…”

Section: Towards An Explanation Of the Chemical Composition Of Ts 01mentioning

confidence: 99%

The chemical composition of TS 01, the most oxygen-deficient planetary nebula

Stasińska

Morisset

Tovmassian

et al. 2010

A&A

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The planetary nebula TS 01 (also called PN G 135.9+55.9 or SBS 1150+599A) with its record-holding low oxygen abundance and its double degenerate close binary core (period 3.9 h) is an exceptional object located in the Galactic halo. We have secured observational data in a complete wavelength range to pin down the abundances of half a dozen elements in the nebula. The abundances are obtained via detailed photoionization modelling which takes into account all the observational constraints (including geometry and aperture effects) using the pseudo-3D photoionization code Cloudy_3D. The spectral energy distribution of the ionizing radiation is taken from appropriate model atmospheres. Incidentally we find from the new observational constraints that both stellar components contribute to the ionization: the "cool" one provides the bulk of hydrogen ionization, while the "hot" one is responsible for the presence of the most highly charged ions, which explains why previous attempts to model the nebula experienced difficulties. The nebular abundances of C, N, O, and Ne are found to be 1/3.5, 1/4.2, 1/70, and 1/11 of the solar value respectively, with uncertainties of a factor 2. Thus the extreme O deficiency of this object is confirmed. The abundances of S and Ar are less than 1/30 of solar. The abundance of He relative to H is 0.089 ± 0.009. Standard models of stellar evolution and nucleosynthesis cannot explain the abundance pattern observed in the nebula. To obtain an extreme oxygen deficiency in a star whose progenitor has an initial mass of about 1 M requires an additional mixing process, which can be induced by stellar rotation and/or by the presence of the close companion. We have computed a stellar model with an initial mass of 1 M , appropriate metallicity, and initial rotation of 100 km s −1 , and find that rotation greatly improves the agreement between the predicted and observed abundances.

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Section: Towards An Explanation Of the Chemical Composition Of Ts 01mentioning

confidence: 99%

The chemical composition of TS 01, the most oxygen-deficient planetary nebula

Stasińska

Morisset

Tovmassian

et al. 2010

A&A

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“…A proper treatment of convection is important for all sorts of things, including making the members of binary systems look the same age (Asiain et al 1997;Pols et al 1997), the location of sunspots (Weiss 1996;De Luca et al 1997) and dynamos , and the extent of composition gradients in stars (Grossman & Taam 1996). Unfortunately, a proper model for convection continues to elude theorists (Castelli et al 1997 and MANY others).…”

Section: Starry Starry Nightmentioning

confidence: 99%

Astrophysics in 1997

Trimble¹,

McFadden²

1998

PUBL ASTRON SOC PAC

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ABSTRACT. Martian marvels, a gamma-ray burster with a redshift, Galileo converses with Ganymede, a record galactic redshift of 4.92, and much else. Fiscal 1997 was definitely an exciting year for astronomers. We have tried hard to hit all the obvious highlights, but also to report more gradual progress on traditional problems of understanding planets, stars, galaxies, and the universe. Though the year was saddened by the loss of many valued colleagues, we nevertheless indulge in occasional soupçons of frivolity.

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“…In this code, we chose a ratio of mixing length, l, to local pressure scale-height, H P , of α = l/H P = 2.0. The convective overshooting parameter in the code, δ ov , is assumed to be 0.12 (Pols et al 1997). The opacity used in our calculations is the same as that compiled by Chen & Tout (2007).…”

Section: Stellar Evolution Codementioning

confidence: 99%

Effects of tidally enhanced stellar wind on the horizontal branch morphology of globular clusters

Lei

Chen

Zhang

et al. 2013

A&A

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Context. Metallicity is the first parameter to influence the horizontal branch (HB) morphology of globular clusters (GCs). It has been found, however, that some other parameters may also play an important role in affecting the morphology. While the nature of these important parameters remains unclear, they are believed to be likely correlated with wind mass-loss of red giants, since this mass loss determines their subsequent locations on the HB. Unfortunately, the mass loss during the red giant stages of the stellar evolution is poorly understood at present. Aims. The stellar winds of red giants may be tidally enhanced by companion stars if they are in binary systems. We investigate the evolutionary consequences of red giants in binaries by including tidally enhanced stellar winds, and examine the effects on the HB morphology of GCs. Methods. We used Eggleton's stellar evolution code to study the binary evolution. The tidally enhanced stellar-wind model of Tout & Eggleton is incorporated into this code, where the tidal enhancement parameter, B w , has various values (e.g., 10 000 and 500) to examine the dependency of the final results on this parameter. A Monte Carlo simulation was performed to generate a group of binary systems. The position of each primary star on the HB in the Hertzsprung-Russell diagram in this sample is obtained through interpolations among the constructed HB evolutionary tracks. Finally, a synthetic HB in the color-magnitude diagram is obtained by transforming the effective temperature and luminosity of each primary star on the HB into B − V colors and absolute magnitude. Results. We find that red, blue, and extreme horizontal branch stars are all produced under the effects of tidally enhanced stellar wind without any additional assumptions on the mass-loss dispersion. Furthermore, the horizontal branch morphology is found to be insensitive to the tidal enhancement parameter, B w . We compare our theoretical results with the observed horizontal branch morphology of globular cluster NGC 2808, and find that the basic morphology of the horizontal branch can be well reproduced. The number of blue horizontal branch stars in our calculations, however, is lower than that of NGC 2808.

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Further critical tests of stellar evolution by means of double-lined eclipsing binaries

Cited by 225 publications

References 0 publications

The chemical composition of TS 01, the most oxygen-deficient planetary nebula

The chemical composition of TS 01, the most oxygen-deficient planetary nebula

Astrophysics in 1997

Effects of tidally enhanced stellar wind on the horizontal branch morphology of globular clusters

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