Die Beziehung zwischen den Massen und den absoluten Leuchtkräften der Sterne

Vogt, Helle

doi:10.1002/asna.19252261903

Cited by 24 publications

(3 citation statements)

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“…Be-cause we have restricted our attention to head-on parabolic collisions, we believe these approximations to be reasonably valid; mass loss and rotational velocity are shown to be small in this case by the simulations of LRS; shock heating is shown to be small and, most importantly, should not affect the distribution of helium-rich gas in the merger remnant (Sec 3.1.2), although it is likely that shock heating will affect the distribution of material near the surface of the star. The form of the energy injection term ǫ x which we use to expand our merger remnant models is constrained by the results of SPH, but its form is nonetheless not crucial as long as significant mixing is not artificially introduced (via the Vogt-Russell Theorem;Vogt 1926, Russell 1927. In comparing the predictions of these models with the blue stragglers seen in two dense clusters, NGC 6397 and 47 Tuc, we have also assumed that all of the blue stragglers in these clusters have been formed through collisions.…”

Section: Discussionmentioning

confidence: 99%

“…We find that, although the tracks that the models follow on the CMD as they expand and contract can differ considerably, the final models that satisfy the above criteria for energy and central density are very similar and evolve identically after they have contracted to the MS. This can be explained using the Vogt-Russell Theorem, which states that the structure of a star in hydrostatic and thermal equilibrium is uniquely determined by the total mass and the run of chemical composition throughout the star (Vogt 1926, Russell 1927; see e.g. Cox & Giuli, 1968).…”

Section: Construction Of Initial Modelsmentioning

confidence: 99%

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The Evolution of Blue Stragglers Formed via Stellar Collisions

Ouellette

1998

The Astronomical Journal

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We have used the results of recent smoothed particle hydrodynamic simulations of colliding stars to create models appropriate for input into a stellar evolution code. In evolving these models, we Ðnd that little or no surface convection occurs, precluding angular momentum loss via a magnetically driven stellar wind as a viable mechanism for slowing rapidly rotating blue stragglers that have been formed by collisions. Angular momentum transfer to either a circumstellar disk (possibly collisional ejecta) or a nearby companion are plausible mechanisms for explaining the observed low rotation velocities of blue stragglers. Under the assumption that the blue stragglers seen in NGC 6397 and 47 Tuc have been created solely by collisions, we Ðnd that the majority of blue stragglers cannot have been highly mixed by convection or meridional circulation currents at any time during their evolution. Also, on the basis of the agreement between the predictions of our nonrotating models and the observed blue straggler distribution, the evolution of blue stragglers is apparently not dominated by the e †ects of rotation.

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Section: Discussionmentioning

confidence: 99%

Section: Construction Of Initial Modelsmentioning

confidence: 99%

The Evolution of Blue Stragglers Formed via Stellar Collisions

Ouellette

1998

The Astronomical Journal

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“…Individual stellar ages are also important for studies of single stars, as the whole physical structure of a star may be determined exclusively from its mass, chemical composition and age (Vogt 1926;Russel et al 1927). Mass and chemical abundances can be directly measured but ages can only be inferred from observable properties that are known to change with time (Soderblom 2010).…”

Section: Introductionmentioning

confidence: 99%

A method to estimate stellar ages from kinematical data

Almeida-Fernandes

Rocha-Pinto

2018

Monthly Notices of the Royal Astronomical Society

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We present a method to build a probability density function (pdf) for the age of a star based on its peculiar velocities U, V and W and its orbital eccentricity. The sample used in this work comes from the Geneva-Copenhagen Survey (GCS) which contains both the spatial velocities, orbital eccentricities and isochronal ages for about 14 000 stars. Using the GCS stars, we fitted the parameters that describe the relations between the distributions of kinematical properties and age. This parametrization allows us to obtain an age probability from the kinematical data. From this age pdf, we estimate an individual average age for the star using the most likely age and the expected age. We have obtained the stellar age pdf for the age of 9 102 stars from the GCS and have shown that the distribution of individual ages derived from our method is in good agreement with the distribution of isochronal ages. We also observe a decline in the mean metallicity with our ages for stars younger than 7 Gyr, similar to the one observed for isochronal ages. This method can be useful for the estimation of rough stellar ages for those stars that fall in areas of the HR diagram where isochrones are tightly crowded. As an example of this method, we estimate the age of Trappist-1, which is a M8V star, obtaining the age of t(UVW ) = 12.50(+0.29 − 6.23) Gyr.

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The Final Stages of Massive Star Evolution and Their Supernovae

Heger

2012

Eta Carinae and the Supernova Impostors

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Die Beziehung zwischen den Massen und den absoluten Leuchtkräften der Sterne

Cited by 24 publications

References 0 publications

The Evolution of Blue Stragglers Formed via Stellar Collisions

The Evolution of Blue Stragglers Formed via Stellar Collisions

A method to estimate stellar ages from kinematical data

The Final Stages of Massive Star Evolution and Their Supernovae

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