The effect of diffusion on solar evolution

1994 ◽  
Vol 426 ◽  
pp. 787 ◽  
Author(s):  
Attay Kovetz ◽  
Giora Shaviv
Keyword(s):  
2019 ◽  
Vol 15 (S356) ◽  
pp. 403-404
Author(s):  
Negessa Tilahun Shukure ◽  
Solomon Belay Tessema ◽  
Endalkachew Mengistu

AbstractSeveral models of the solar luminosity, , in the evolutionary timescale, have been computed as a function of time. However, the solar mass-loss, , is one of the drivers of variation in this timescale. The purpose of this study is to model mass-loss varying solar luminosity, , and to predict the luminosity variation before it leaves the main sequence. We numerically computed the up to 4.9 Gyrs from now. We used the solution to compute the modeled . We then validated our model with the current solar standard model (SSM). The shows consistency up to 8 Gyrs. At about 8.85 Gyrs, the Sun loses 28% of its mass and its luminosity increased to 2.2. The model suggests that the total main sequence lifetime is nearly 9 Gyrs. The model explains well the stage at which the Sun exhausts its central supply of hydrogen and when it will be ready to leave the main sequence. It may also explain the fate of the Sun by making some improvements in comparison to previous models.


2021 ◽  
Vol 18 (1) ◽  
Author(s):  
Jørgen Christensen-Dalsgaard

AbstractThe Sun provides a critical benchmark for the general study of stellar structure and evolution. Also, knowledge about the internal properties of the Sun is important for the understanding of solar atmospheric phenomena, including the solar magnetic cycle. Here I provide a brief overview of the theory of stellar structure and evolution, including the physical processes and parameters that are involved. This is followed by a discussion of solar evolution, extending from the birth to the latest stages. As a background for the interpretation of observations related to the solar interior I provide a rather extensive analysis of the sensitivity of solar models to the assumptions underlying their calculation. I then discuss the detailed information about the solar interior that has become available through helioseismic investigations and the detection of solar neutrinos, with further constraints provided by the observed abundances of the lightest elements. Revisions in the determination of the solar surface abundances have led to increased discrepancies, discussed in some detail, between the observational inferences and solar models. I finally briefly address the relation of the Sun to other similar stars and the prospects for asteroseismic investigations of stellar structure and evolution.


2020 ◽  
Vol 498 (2) ◽  
pp. 1992-2000
Author(s):  
Diogo Capelo ◽  
Ilídio Lopes

ABSTRACT The Sun is the most studied and well-known star, and as such, solar fundamental parameters are often used to bridge gaps in the knowledge of other stars, when these are required for modelling. However, the two most powerful and precise independent methodologies currently available to infer the internal solar structure are in disagreement. We aim to show the potential impact of composition choices in the overall evolution of a star, using the Sun as example. To this effect, we create two Standard Solar Models and a comparison model using different combinations of metallicity and relative element abundances and compare evolutionary, helioseismic, and neutrino-related properties for each. We report differences in age for models calibrated to the same point on the HR diagram, in red giant branch, of more than 1 Gyr, and found that the current precision level of asteroseismic measurements is enough to differentiate these models, which would exhibit differences in period spacing of 1.30–2.58 per cent. Additionally, we show that the measurement of neutrino fluxes from the carbon–nitrogen–oxygen cycle with a precision of around 17 per cent, which could be achieved by the next generation of solar neutrino experiments, could help resolve the stellar abundance problem.


1960 ◽  
Vol 65 ◽  
pp. 484 ◽  
Author(s):  
R. R. Brownlee ◽  
A. N. Cox
Keyword(s):  

2007 ◽  
Author(s):  
Ilídio Lopes ◽  
Dário Passos ◽  
Richard J. Stancliffe ◽  
Guenter Houdek ◽  
Rebecca G. Martin ◽  
...  
Keyword(s):  

Terra Nova ◽  
2014 ◽  
Vol 26 (4) ◽  
pp. 282-286 ◽  
Author(s):  
David Waltham
Keyword(s):  

Eos ◽  
1979 ◽  
Vol 60 (2) ◽  
pp. 18
Author(s):  
Carl Sagan ◽  
Gordon Newkirk
Keyword(s):  

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