Single star evolution I. Massive stars and early evolution of low and intermediate mass stars

1984 ◽  
Vol 105 (6) ◽  
pp. 329-406 ◽  
Author(s):  
Icko Iben ◽  
Alvio Renzini
Keyword(s):  
Massive Stars ◽  
Early Evolution ◽  
Intermediate Mass ◽  
Single Star ◽  
Intermediate Mass Stars ◽  
Star Evolution

scholarly journals The effects of Rotation on Wolf–Rayet Stars and on the Production of Primary Nitrogen by Intermediate Mass Stars

2004 ◽  
Vol 215 ◽  
pp. 579-588 ◽  
Author(s):  
Georges Meynet ◽  
Max Pettini
Keyword(s):  
Star Formation ◽  
Time Delay ◽  
Main Sequence ◽  
Massive Stars ◽  
Sequence Evolution ◽  
Stellar Rotation ◽  
Intermediate Mass ◽  
Intermediate Mass Stars ◽  
Solar Metallicity ◽  
Effects Of Rotation

We use the rotating stellar models described in the paper by A. Maeder & G. Meynet in this volume to consider the effects of rotation on the evolution of the most massive stars into and during the Wolf–Rayet phase, and on the post-Main Sequence evolution of intermediate mass stars. The two main results of this discussion are the following. First, we show that rotating models are able to account for the observed properties of the Wolf–Rayet stellar populations at solar metallicity. Second, at low metallicities, the inclusion of stellar rotation in the calculation of chemical yields can lead to a longer time delay between the release of oxygen and nitrogen into the interstellar medium following an episode of star formation, since stars of lower masses (compared to non-rotating models) can synthesize primary N. Qualitatively, such an effect may be required to explain the relative abundances of N and O in extragalactic metal–poor environments, particularly at high redshifts.

scholarly journals Binary Central Stars of Planetary Nebulae

Galaxies ◽  
2020 ◽  
Vol 8 (2) ◽  
pp. 28 ◽  
Author(s):  
David Jones
Keyword(s):  
Planetary Nebulae ◽  
Current Understanding ◽  
Intermediate Mass ◽  
Single Star ◽  
Intermediate Mass Stars ◽  
Binary Evolution ◽  
Central Stars

It is now clear that a vast majority of intermediate-mass stars have stellar and/or sub-stellar companions, therefore it is no longer appropriate to consider planetary nebulae as a single-star phenomenon, although some single, isolated stars may well lead to planetary nebulae. As such, while understanding binary evolution is critical for furthering our knowledge of planetary nebulae, the converse is also true: planetary nebulae can be valuable tools with which to probe binary evolution. In this brief review, I attempt to summarise some of our current understanding with regards to the role of binarity in the formation of planetary nebulae, and the areas in which continued study of planetary nebulae may have wider ramifications for our grasp on the fundaments of binary evolution.

Spectroscopy of complete populations of Wolf-Rayet binaries in the Magellanic Clouds

2018 ◽  
Vol 14 (S346) ◽  
pp. 307-315
Author(s):  
Tomer Shenar ◽  
R. Hainich ◽  
W.-R. Hamann ◽  
A. F. J. Moffat ◽  
H. Todt ◽  
...  
Keyword(s):  
Spectral Analysis ◽  
Mass Loss ◽  
Massive Stars ◽  
Large Population ◽  
Magellanic Clouds ◽  
Binary Interaction ◽  
Stellar Winds ◽  
Single Star ◽  
Mass Removal ◽  
Star Evolution

AbstractClassical Wolf-Rayet stars are evolved, hydrogen depleted massive stars that exhibit strong mass-loss. In theory, these stars can form either by intrinsic mass loss (stellar winds or eruptions), or via mass-removal in binaries. The Wolf-Rayet stars in the Magellanic Clouds are often thought to have originated through binary interaction due to the low ambient metallicity and, correspondingly, reduced wind mass-loss. We performed a complete spectral analysis of all known WR binaries of the nitrogen sequence in the Small and Large Magellanic Clouds, as well as additional orbital analyses, and constrained the evolutionary histories of these stars. We find that the bulk of Wolf-Rayet stars are luminous enough to be explained by single-star evolution. In contrast to prediction, we do not find clear evidence for a large population of low-luminosity Wolf-Rayet stars that could only form via binary interaction, suggesting a discrepancy between predictions and observations.

scholarly journals SMBH Luminosity in the Starburst Environment

2009 ◽  
Vol 5 (S267) ◽  
pp. 336-336
Author(s):  
Sergiy Silich ◽  
Guillermo Tenorio-Tagle ◽  
Filiberto Hueyotl-Zahuantitla ◽  
Jan Palouš ◽  
Richard Wünsch
Keyword(s):  
Mass Loss ◽  
Loss Rate ◽  
Accretion Rate ◽  
Massive Stars ◽  
Mass Loss Rate ◽  
Intermediate Mass ◽  
Star Forming ◽  
Intermediate Mass Stars

We claim that in the starburst environment there is no accretion of the ISM onto the BH and thus, in such cases, the BH luminosity is regulated by the mass-loss rate from massive stars in the star forming region. We calculate the accretion rate and show that it is usually small during the superwind stage and grows at the post-starburst stage, when the matter reinserted by intermediate–mass stars remains gravitationally bound and fuels the central BH.

scholarly journals s-Process Enrichment in Low-Mass Agb Stars

1989 ◽  
Vol 106 ◽  
pp. 176-195 ◽  
Author(s):  
R. Gallino
Keyword(s):  
Solar System ◽  
Massive Stars ◽  
Agb Stars ◽  
Intermediate Mass ◽  
Low Mass Stars ◽  
Temporal Behaviour ◽  
Physical Conditions ◽  
Intermediate Mass Stars ◽  
Low Mass ◽  
Main Component

AbstractAfter a brief description of the developments of the theory of s-process nucleosynthesis, the difficulties recently encountered in envisaging reliable astrophysical conditions for obtaining a solar-system distribution of s-isotopes are discussed. In particular, while the reaction 22Ne(α, n)25Mg may account for the nucleosynthesis of the weak s-component in massive stars, it fails to reproduce the main s-component in intermediate mass stars. The efficiency of the alternative reaction 13C(α, n)160 occurring in low mass stars during recurring thermal instabilities of the He shell is then analyzed. It is shown that, contrary to previous expectations, the 13C source well reproduces the main component, provided that realistic physical conditions are assumed for the temporal behaviour of the pulse and the effect of the light n-absorbers (especially 12C) is properly taken into account. The results satisfactorily compare with the constraints of the classical s-analysis. Key observational evidences also appear to be in agreement with this scenario.

scholarly journals On the Star-formation History in the LMC: Observations of the Interstellar C18O/C17O Ratio

1999 ◽  
Vol 190 ◽  
pp. 275-276
Author(s):  
Arto Heikkilä ◽  
Lars E.B. Johansson ◽  
Hans Olofsson
Keyword(s):  
Star Formation ◽  
Massive Stars ◽  
Density Ratio ◽  
Abundance Ratio ◽  
Initial Mass Function ◽  
Star Formation History ◽  
Intermediate Mass ◽  
Stellar Nucleosynthesis ◽  
Intermediate Mass Stars ◽  
Formation History

The re-cycling of gas between stars and the interstellar medium (ISM) leads to a gradual metal-enrichment of a galaxy. Accordingly, information on the chemical evolution of a galaxy, e.g., its star-formation history (SFH), is contained in the chemical composition of the ISM. In this context, the abundance ratio of the rare oxygen isotopes, 18O/17O (usually taken as the C18O/C17O column density ratio), appears to be a particularly promising probe of the SFH. According to present understanding of stellar nucleosynthesis, 17O is mainly produced in intermediate-mass stars (say a few to ten M⊙) while 18O is synthesised in massive stars (say >10M⊙) (e.g., Prantzos et al. 1996). Thus, the 18O/17O abundance ratio possibly reflects the relative number of massive stars compared to intermediate-mass stars, and thereby (qualitatively) constrains the SFH in terms of the average star-formation rate (SFR) and the initial mass-function (IMF). However, it should be remembered that the stellar nucleosynthesis of 17,18O is not yet fully understood, leaving room for other interpretations of the 18O/17O ratio.

scholarly journals The fates of massive stars: exploring uncertainties in stellar evolution with metisse

2020 ◽  
Vol 497 (4) ◽  
pp. 4549-4564
Author(s):  
Poojan Agrawal ◽  
Jarrod Hurley ◽  
Simon Stevenson ◽  
Dorottya Szécsi ◽  
Chris Flynn
Keyword(s):  
Stellar Evolution ◽  
Main Sequence ◽  
Massive Stars ◽  
Mass Range ◽  
Radial Expansion ◽  
Single Star ◽  
New Approach ◽  
Star Evolution ◽  
Order Of Magnitude ◽  
The Impact

ABSTRACT In the era of advanced electromagnetic and gravitational wave detectors, it has become increasingly important to effectively combine and study the impact of stellar evolution on binaries and dynamical systems of stars. Systematic studies dedicated to exploring uncertain parameters in stellar evolution are required to account for the recent observations of the stellar populations. We present a new approach to the commonly used single-star evolution (sse) fitting formulae, one that is more adaptable: method of interpolation for single star evolution (metisse). It makes use of interpolation between sets of pre-computed stellar tracks to approximate evolution parameters for a population of stars. We have used metisse with detailed stellar tracks computed by the modules for experiments in stellar astrophysics (mesa), the bonn evolutionary code (bec), and the Cambridge stars code. metisse better reproduces stellar tracks computed using the stars code compared to sse, and is on average three times faster. Using stellar tracks computed with mesa and bec, we apply metisse to explore the differences in the remnant masses, the maximum radial expansion, and the main-sequence lifetime of massive stars. We find that different physical ingredients used in the evolution of stars, such as the treatment of radiation-dominated envelopes, can impact their evolutionary outcome. For stars in the mass range 9–100 M⊙, the predictions of remnant masses can vary by up to 20 M⊙, while the maximum radial expansion achieved by a star can differ by an order of magnitude between different stellar models.

scholarly journals Commission 35: Stellar Constitution: (Constitution Des Etoiles)

2000 ◽  
Vol 24 (1) ◽  
pp. 201-218
Author(s):  
J.-P. Zahn ◽  
D. VandenBerg ◽  
R. Canal ◽  
C. Chiosi ◽  
W. Dziembowski ◽  
...  
Keyword(s):  
White Dwarfs ◽  
Massive Stars ◽  
Atomic Diffusion ◽  
Intermediate Mass ◽  
Low Mass Stars ◽  
The Past ◽  
Intermediate Mass Stars ◽  
Low Mass

Our Commission decided to proceed as before, with a rather comprehensive report, while focusing on the subjects where most progress has been achieved during the past three years. The colleagues who kindly contributed to it are W. Dziembowski (helio- and aster-oseismology), J. Guzik (intermediate-mass stars), G. Meynet (massive stars), G. Michaud (atomic diffusion), D. VandenBerg (low mass stars), G. Vauclair (white dwarfs), J.-P. Zahn (convection, rotational mixing).

scholarly journals Low Mass Wolf-Rayet Stars: Theory

1982 ◽  
Vol 99 ◽  
pp. 413-422 ◽  
Author(s):  
Alvio Renzini
Keyword(s):  
Massive Stars ◽  
Asymptotic Giant Branch ◽  
Intermediate Mass ◽  
Helium Burning ◽  
Hydrogen Burning ◽  
Intermediate Mass Stars ◽  
Low Mass ◽  
Chandrasekhar Limit ◽  
Central Stars ◽  
Evolutionary Product

It is well known that the Wolf-Rayet phenomenon is not restricted to some bright and massive stars, presumably in their core hydrogen-burning or helium-burning phase, but that it is also encountered among the central stars of some planetary nebulae (PNe). The PN nuclei are generally regarded as the evolutionary product of low and intermediate mass stars (with initial masses M.1 below ∼5 M⊙), which have lost most of their hydrogen-rich envelope during the so-called Asymptotic Giant Branch (AGB) phase. Correspondingly, their present mass cannot exceed the Chandrasekhar limit (∼1.4 M⊙), and their internal structure consists of a highly degenerate carbon-oxygen core containing most of the stellar mass, surrounded by an intershell region of mass ΔMCSH, and by a very low-mass envelope (Me < ∼10−3 M⊙).

Sign in / Sign up

Export Citation Format

Share Document