EARLY AND MAIN SEQUENCE EVOLUTION OF STARS IN THE RANGE 0.5 TO 100 SOLAR MASSES

1967 ◽  
Vol 45 (11) ◽  
pp. 3429-3460 ◽  
Author(s):  
Dilhan Ezer ◽  
A. G. W. Cameron
Keyword(s):  
Mass Loss ◽  
Main Sequence ◽  
Mass Range ◽  
Energy Stability ◽  
Sequence Evolution ◽  
The Sun ◽  
Solar Mass ◽  
Mass Model ◽  
Evolutionary Study ◽  
Evolutionary Studies

The evolutionary study previously carried out for the sun has been extended to stars of 0.5, 0.7, 2, 5, 10, 20, 50, and 100 solar masses. The evolutionary calculations were started at the threshold of energy stability, carried through the approach to the main sequence, and (with the exception of the 100 solar-mass model) through the depletion of hydrogen on the main sequence. All models were observed to have a completely convective Hayashi phase. There was general agreement, in the appropriate mass range, with the evolutionary studies of Iben, the discrepancies apparently resulting from different opacities used in the calculations. Lines of equal evolutionary age in a Hertzsprung–Russell diagram constructed from these calculations do not agree with the observations of Walker, probably because of the neglect of mass loss and rotation in the early stellar evolutionary histories.

scholarly journals Mass-loss varying luminosity and its implication to the solar evolution

2019 ◽  
Vol 15 (S356) ◽  
pp. 403-404
Author(s):  
Negessa Tilahun Shukure ◽  
Solomon Belay Tessema ◽  
Endalkachew Mengistu
Keyword(s):  
Standard Model ◽  
Mass Loss ◽  
Main Sequence ◽  
The Sun ◽  
Solar Mass ◽  
Solar Luminosity ◽  
Solar Evolution

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.

scholarly journals Search for stellar companions of exoplanet host stars by exploring the second ESA-Gaia data release

2019 ◽  
Vol 490 (4) ◽  
pp. 5088-5102 ◽  
Author(s):  
M Mugrauer
Keyword(s):  
Main Sequence ◽  
Stellar Systems ◽  
Sequence Evolution ◽  
The Sun ◽  
M Dwarfs ◽  
Primary Star ◽  
True Nature ◽  
Quadruple System ◽  
Data Release ◽  
Host Stars

ABSTRACT A new survey is presented, which explores the second data release of the ESA-Gaia mission, in order to search for stellar companions of exoplanet host stars, located at distances closer than about 500 pc around the Sun. In total, 176 binaries, 27 hierarchical triples, and one hierarchical quadruple system are detected among more than 1300 exoplanet host stars, whose multiplicity is investigated, yielding a multiplicity rate of the exoplanet host stars of at least about 15  per cent. The detected companions and the exoplanet host stars are equidistant and share a common proper motion, as it is expected for gravitationally bound stellar systems, proven with their accurate Gaia astrometry. The companions exhibit masses in the range between about 0.078 and 1.4 M⊙ with a peak in their mass distribution between 0.15 and $0.3\, \mathrm{M}_{\odot }$. The companions are separated from the exoplanet host stars by about 20 up to 9100 au, but are found most frequently within a projected separation of 1000 au. While most of the detected companions are early M dwarfs, eight white dwarf companions of exoplanet host stars are also identified in this survey, whose true nature is revealed with their photometric properties. Hence, these degenerated companions and the exoplanet host stars form evolved stellar systems with exoplanets, which have survived (physically but also dynamically) the post-main-sequence evolution of their former primary star.

scholarly journals Properties of massive Population III and metal-poor stars

2006 ◽  
Vol 2 (14) ◽  
pp. 211-211
Author(s):  
Daniel Schaerer
Keyword(s):  
Mass Loss ◽  
Power Law ◽  
Main Sequence ◽  
Sequence Evolution ◽  
Solar Metallicity ◽  
Log Normal ◽  
Loss Mechanisms ◽  
Population Iii

AbstractWe review the properties of massive Population III and very metal-poor stars, including briefly their formation, IMF, their main sequence evolution, possible mass loss mechanisms, atmosphere modeling etc. For detailed predictions concerning the properties of these stars we refer to Schaerer (2002) and Schaerer (2002) and references therein. Extending these calculations, Schaerer (2007) present new calculations concerning the ionizing power, Ly-α strength and related properties for different metallicities as well as for a range of power-law and log-normal IMFs. For illustrations from these studies see the Figures below. New detailed calibrations for solar metallicity O-type stars have recently been presented by Martins et al. (2005).

scholarly journals Swansong biospheres II: the final signs of life on terrestrial planets near the end of their habitable lifetimes

2014 ◽  
Vol 13 (3) ◽  
pp. 229-243 ◽  
Author(s):  
Jack T. O'Malley-James ◽  
Charles S. Cockell ◽  
Jane S. Greaves ◽  
John A. Raven
Keyword(s):  
Environmental Conditions ◽  
Late Stage ◽  
Cloud Cover ◽  
Main Sequence ◽  
Interaction Model ◽  
Early Earth ◽  
Sequence Evolution ◽  
The Sun ◽  
Upper Limit ◽  
Life On Earth

AbstractThe biosignatures of life on Earth do not remain static, but change considerably over the planet's habitable lifetime. Earth's future biosphere, much like that of the early Earth, will consist of predominantly unicellular microorganisms due to the increased hostility of environmental conditions caused by the Sun as it enters the late stage of its main sequence evolution. Building on previous work, the productivity of the biosphere is evaluated during different stages of biosphere decline between 1 and 2.8 Gyr from present. A simple atmosphere–biosphere interaction model is used to estimate the atmospheric biomarker gas abundances at each stage and to assess the likelihood of remotely detecting the presence of life in low-productivity, microbial biospheres, putting an upper limit on the lifetime of Earth's remotely detectable biosignatures. Other potential biosignatures such as leaf reflectance and cloud cover are discussed.

Effects of mass loss on the evolution of massive stars. I - Main-sequence evolution

1978 ◽  
Vol 223 ◽  
pp. 552 ◽  
Author(s):  
D. S. P. Dearborn ◽  
J. B. Blake ◽  
K. L. Hainebach ◽  
D. N. Schramm
Keyword(s):  
Mass Loss ◽  
Main Sequence ◽  
Massive Stars ◽  
Sequence Evolution

scholarly journals Progenitor for Type Ic Supernova 2007bi

2011 ◽  
Vol 7 (S279) ◽  
pp. 427-428
Author(s):  
Takashi Yoshida ◽  
Hideyuki Umeda
Keyword(s):  
Light Curve ◽  
Mass Loss ◽  
Loss Rate ◽  
Main Sequence ◽  
Massive Stars ◽  
Mass Loss Rate ◽  
Mass Range ◽  
Stellar Mass ◽  
Core Collapse ◽  
Core Collapse Supernova

AbstractWe investigate the evolution of very massive stars with Z = 0.2 Z⊙ to constrain the progenitor of the extremely luminous Type Ic SN 2007bi. In order to reproduce the 56Ni amount produced in SN 2007bi, the range of the stellar mass at the zero-age main-sequence is expected to be 515 - 575M⊙ for pair-instability supernova and 110 - 280M⊙ for core-collapse supernova. Uncertainty in the mass loss rate affects the mass range appropriate for the explosion of SN 2007bi. A core-collapse supernova of a WO star evolved from a 110 M⊙ star produces sufficient radioactive 56Ni to reproduce the light curve of SN 2007bi.

ON THE THEORY OF GAMMA RAY BURSTS AND HYPERNOVAE: THE BLACK HOLE SOFT X-RAY TRANSIENT SOURCES

2003 ◽  
Vol 18 (04) ◽  
pp. 527-576 ◽  
Author(s):  
CHANG-HWAN LEE ◽  
GERALD E. BROWN
Keyword(s):  
Mass Transfer ◽  
Black Hole ◽  
Mass Loss ◽  
Evolutionary History ◽  
Main Sequence ◽  
Gamma Ray ◽  
Supernova Explosion ◽  
Sequence Evolution ◽  
X Ray ◽  
Black Hole Binaries

We show that a common evolutionary history can produce the black hole binaries in the Galaxy in which the black holes have masses of ~ 5 - 10M⊙. In the black hole binaries with low-mass, ≲ 2.5M⊙ ZAMS (zero age main sequence) companions, the latter remain in main sequence during the active stage of soft X-ray transients (SXT's), most of them being of K or M classification. In two intermediate cases, IL Lupi and Nova Scorpii with ZAMS ~ 2.5M⊙ companions the orbits are greatly widened because of large mass loss in the explosion forming the black hole, and whereas these companions are in late main sequence evolution, they are close to evolving. Binaries with companion ZAMS masses ≳ 3M⊙ are initially "silent" until the companion begins evolving across the Herzsprung gap. We provide evidence that the narrower, shorter period binaries, with companions now in main sequence, are fossil remnants of gamma ray bursters (GRB's). We also show that the GRB is generally accompanied by a hypernova explosion (a very energetic supernova explosion). We further show that the binaries with evolved companions are good models for some of the ultraluminous X-ray sources (ULX's) recently seen by Chandra in other galaxies. The great regularity in our evolutionary history, especially the fact that most of the companions of ZAMS mass ≲ 2.5M⊙ remain in main sequences as K or M stars can be explained by the mass loss in common envelope evolution to be Case C; i.e. to occur only after core He burning has finished. Since our argument for Case C mass transfer is not generally understood in the community, we add an appendix, showing that with certain assumptions which we outline we can reproduce the regularities in the evolution of black hole binaries by Case C mass transfer.

The Effects of Post-Main-Sequence Solar Mass Loss on the Stability of Our Planetary System

Icarus ◽  
1998 ◽  
Vol 134 (2) ◽  
pp. 303-310 ◽  
Author(s):  
Martin J. Duncan ◽  
Jack J. Lissauer
Keyword(s):  
Mass Loss ◽  
Main Sequence ◽  
Planetary System ◽  
Solar Mass ◽  
The Stability

scholarly journals Mathematical model for the 0.5 billion years aged Sun

2000 ◽  
pp. 35-40
Author(s):  
E. Tatomir
Keyword(s):  
Energy Source ◽  
Mathematical Model ◽  
Numerical Integration ◽  
Main Sequence ◽  
Solar Model ◽  
System Of Equations ◽  
The Sun ◽  
Solar Mass ◽  
Proton Proton ◽  
Close Vicinity

An algorithm is given for constructing evolutionary tracks for a star with the mass equal to one solar mass. The presented model can be applied to the stars belonging to the inferior main sequence, which have the proton-proton reaction as energy source and present a radiative core and a convective shell. This paper presents an original way of solving the system of equations corresponding to the radiative nucleus by using Taylor?s series in close vicinity to the center of the Sun. It also presents the numerical integration and the results for a 0.5 billion years aged solar model.

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