A New Version of Reimers' Law of Mass Loss Based on a Physical Approach

Schröder, K.-P.; Cuntz, M.

doi:10.1086/491579

Cited by 250 publications

(356 citation statements)

References 30 publications

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“…1, 2 & 3) for C-rich winds. The LPCODE models adopt the empirical law by Groenewegen et al (1998) for the C-rich phase while winds for the O-rich phase mostly follow the Schröder & Cuntz (2005) law. These laws appear as eqs.…”

Section: Description Of the Model Codesmentioning

confidence: 99%

On the production of He, C, and N by low- and intermediate-mass stars: a comparison of observed and model-predicted planetary nebula abundances

Henry

Stephenson

Bertolami

et al. 2017

Monthly Notices of the Royal Astronomical Society

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The primary goal of this paper is to make a direct comparison between the measured and modelpredicted abundances of He, C and N in a sample of 35 well-observed Galactic planetary nebulae (PN). All observations, data reductions, and abundance determinations were performed in house to ensure maximum homogeneity. Progenitor star masses (M ≤ 4 M ⊙ ) were inferred using two published sets of post-AGB model tracks and L and T ef f values. We conclude the following: 1) the mean values of N/O across the progenitor mass range exceeds the solar value, indicating significant N enrichment in the majority of our objects; 2) the onset of hot bottom burning appears to begin around 2 M ⊙ , i.e., lower than ∼ 5 M ⊙ implied by theory; 3) most of our objects show a clear He enrichment, as expected from dredge-up episodes; 4) the average sample C/O value is 1.23, consistent with the effects of third dredge-up; and 5) model grids used to compare to observations successfully span the distribution over metallicity space of all C/O and many He/H data points but mostly fail to do so in the case of N/O. The evident enrichment of N in PN and the general discrepancy between the observed and model-predicted N/O abundance ratios signal the need for extra-mixing as an effect of rotation and/or thermohaline mixing in the models. The unexpectedly high N enrichment that is implied here for low mass stars, if confirmed, will likely impact our conclusions about the source of N in the Universe.

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Section: Description Of the Model Codesmentioning

confidence: 99%

On the production of He, C, and N by low- and intermediate-mass stars: a comparison of observed and model-predicted planetary nebula abundances

Henry

Stephenson

Bertolami

et al. 2017

Monthly Notices of the Royal Astronomical Society

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“…Mass-loss on the RGB is described by a version of Reimers' law (Reimers 1975) based on a physical approach by Schröder & Cuntz (2005):…”

Section: The Stellar Evolution Code and Input Physicsmentioning

confidence: 99%

Gravitational settling in pulsating subdwarf B stars and their progenitors

Glebbeek

Thoul

et al. 2010

A&A

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Context. Diffusion of atoms can be important during quiescent phases of stellar evolution. Particularly in the very thin inert envelopes of subdwarf B stars, diffusive movements will considerably change the envelope structure and the surface abundances on a short timescale. Also, the subdwarfs will inherit the effects of diffusion in their direct progenitors, namely giants near the tip of the red giant branch. This will influence the global evolution and the pulsational properties of subdwarf B stars. Aims. We investigate the impact of gravitational settling, thermal diffusion and concentration diffusion on the evolution and pulsations of subdwarf B stars. Although radiative levitation is not explicitly calculated, we evaluate its effect by approximating the resulting iron accumulation in the driving region. This allows us to study the excitation of the pulsation modes, albeit in a parametric fashion. Our diffusive stellar models are compared with models evolved without diffusion. Methods. We use a detailed stellar evolution code to solve simultaneously the equations of stellar structure and evolution, including the composition changes due to diffusion. The diffusion calculations are performed for a multicomponent fluid using diffusion coefficients derived from a screened Coulomb potential. We constructed subdwarf B models with a mass of 0.465 M from a 1 M and 3 M zero-age main sequence progenitor. The low mass star ignited helium in an energetic flash, while the intermediate mass star started helium fusion gently. For each progenitor type we computed series with and without atomic diffusion. Results. Atomic diffusion in red giants causes the helium core mass at the onset of helium ignition to be larger. We find an increase of 0.0015 M for the 1 M model and 0.0036 M for the 3 M model. The effects on the red giant surface abundances are small after the first dredge up. The evolutionary tracks of the diffusive subdwarf B models are shifted to lower surface gravities and effective temperatures due to outward diffusion of hydrogen. This affects both the frequencies of the excited modes and the overall frequency spectrum. Especially the structure and pulsations of the post-non-degenerate sdB star are drastically altered, proving that atomic diffusion cannot be ignored in these stars. Sinking of metals could to some extent increase the gravities and temperatures due to the associated decrease in the stellar opacity. However, this effect should be limited as it is counteracted by radiative levitation.

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“…Our models are based on advanced version of the Eggleton stellar evolution code that considers updated opacities and an updated equation of state as described by Pols et al (1995Pols et al ( , 1998. Additionally, an improved description of mass loss is implemented following the work by Schröder & Cuntz (2005).…”

Section: Discussionmentioning

confidence: 99%

Habitability of super-Earth planets around main-sequence stars including red giant branch evolution: models based on the integrated system approach

Cuntz

Bloh

Schröder

et al. 2011

International Journal of Astrobiology

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In a previous study published in Astrobiology, we focused on the evolution of habitability of a 10 M ⊕ super-Earth planet orbiting a star akin to the Sun. This study was based on a concept of planetary habitability in accordance to the integrated system approach that describes the photosynthetic biomass production taking into account a variety of climatological, biogeochemical, and geodynamical processes. In the present study, we pursue a significant augmentation of our previous work by considering stars with zero-age main sequence masses between 0.5 and 2.0 M ⊙ with special emphasis on models of 0.8, 0.9, 1.2 and 1.5 M ⊙ . Our models of habitability consider again geodynamical processes during the mainsequence stage of these stars as well as during their red giant branch evolution. Pertaining to the different types of stars, we identify so-called photosynthesissustaining habitable zones (pHZ) determined by the limits of biological productivity on the planetary surface. We obtain various sets of solutions consistent with the principal possibility of life. Considering that stars of relatively high masses depart from the main-sequence much earlier than low-mass stars, it is found that the biospheric life-span of super-Earth planets of stars with masses above approximately 1.5 M ⊙ is always limited by the increase in stellar luminosity. However, for stars with masses below 0.9 M ⊙ , the life-span of super-Earths is solely determined by the geodynamic time-scale. For central star masses between 0.9 and 1.5 M ⊙ , the possibility of life in the framework of our models depends on the relative continental area of the super-Earth planet.-2 -

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A New Version of Reimers' Law of Mass Loss Based on a Physical Approach

Cited by 250 publications

References 30 publications

On the production of He, C, and N by low- and intermediate-mass stars: a comparison of observed and model-predicted planetary nebula abundances

On the production of He, C, and N by low- and intermediate-mass stars: a comparison of observed and model-predicted planetary nebula abundances

Gravitational settling in pulsating subdwarf B stars and their progenitors

Habitability of super-Earth planets around main-sequence stars including red giant branch evolution: models based on the integrated system approach

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