scholarly journals A Large Stellar Evolution Database for Population Synthesis Studies. III. Inclusion of the Full Asymptotic Giant Branch Phase and Web Tools for Stellar Population Analyses

2007 ◽  
Vol 133 (2) ◽  
pp. 468-478 ◽  
Author(s):  
Daniel Cordier ◽  
Adriano Pietrinferni ◽  
Santi Cassisi ◽  
Maurizio Salaris
Keyword(s):  
Stellar Evolution ◽  
Stellar Population ◽  
Asymptotic Giant Branch ◽  
Population Synthesis ◽  
Population Analyses ◽  
Web Tools

scholarly journals Population Synthesis: Challenges for the Next Decade

2009 ◽  
Vol 5 (S262) ◽  
pp. 55-64
Author(s):  
Gustavo Bruzual A.
Keyword(s):  
Stellar Evolution ◽  
Stellar Population ◽  
Stellar Model ◽  
Data Sets ◽  
Population Synthesis ◽  
Current Interest ◽  
Recent Advances ◽  
Stellar Population Synthesis ◽  
Spectral Libraries

AbstractIn this paper I present a brief summary of recent advances in the fields of stellar evolution, stellar model atmospheres, and stellar spectral libraries, which allow us to build more realistic stellar population synthesis models than those available up to now. Applications of these models to problems of current interest are discussed. Problems that need to be understood and data sets that need to be collected in order to solve issues present in these models are listed.

scholarly journals TP-AGB stars in population synthesis models

2009 ◽  
Vol 5 (S262) ◽  
pp. 36-43 ◽  
Author(s):  
Paola Marigo ◽  
Léo Girardi ◽  
Alessandro Bressan ◽  
Bernhard Aringer ◽  
Marco Gullieuszik ◽  
...  
Keyword(s):  
Mass Loss ◽  
Stellar Evolution ◽  
Magellanic Clouds ◽  
Asymptotic Giant Branch ◽  
Agb Stars ◽  
Population Synthesis ◽  
Future Developments ◽  
First Results ◽  
Nearby Galaxies ◽  
The Subject

AbstractIn spite of its relevance, the Thermally Pulsing Asymptotic Giant Branch (TP-AGB) phase is one of the most uncertain phases of stellar evolution, and a major source of disagreement between the results of different population synthesis models of galaxies. I will briefly review the existing literature on the subject, and recall the basic prescriptions that have been used to fix the contribution of TP-AGB stars to the integrated light of stellar populations. The simplicity of these prescriptions greatly contrasts with the richness of details provided by present-day databases of AGB stars in the Magellanic Clouds, which are now being extended to other nearby galaxies. I will present the first results of an ongoing study aimed at simulating photometry, chemistry, pulsation, mass loss, dust properties of AGB star populations in resolved and un-resolved galaxies. We test our predictions against observations from various surveys of the Magellanic Clouds (DENIS, 2MASS, OGLE, MACHO, Spitzer, and AKARI). I will discuss the implications and outline the plan of future developments.

scholarly journals A new method to identify subclasses among AGB stars using Gaia and 2MASS photometry

2018 ◽  
Vol 616 ◽  
pp. L13 ◽  
Author(s):  
T. Lebzelter ◽  
N. Mowlavi ◽  
P. Marigo ◽  
G. Pastorelli ◽  
M. Trabucchi ◽  
...  
Keyword(s):  
Stellar Population ◽  
Chemical Properties ◽  
Large Magellanic Cloud ◽  
Asymptotic Giant Branch ◽  
Red Giants ◽  
Agb Stars ◽  
Population Synthesis ◽  
Stellar Population Synthesis ◽  
Low Mass ◽  
Spectral Ranges

Aims. We explore the wealth of high-quality photometric data provided by data release 2 (DR2) of the Gaia mission for long-period variables (LPVs) in the Large Magellanic Cloud (LMC). Our goal is to identify stars of various types and masses along the asymptotic giant branch. Methods. For this endeavour, we developed a new multi-band approach combining Wesenheit functions WRP,BP−RP and WKs,J−Ks in the Gaia BP, RP, and 2MASS J, Ks spectral ranges, respectively, and use a new diagram, (WRP,BP−RP − WKs,J−Ks) versus Ks, to distinguish between different kinds of stars in our sample of LPVs. We used stellar population synthesis models to validate our approach. Results. We demonstrate the ability of the new diagram to discriminate between O- and C-rich objects, and to identify low-mass, intermediate-mass, and massive O-rich red giants, as well as extreme C-rich stars. Stellar evolution and population synthesis models guide the interpretation of the results, highlighting the diagnostic power of the new tool to discriminate between stellar initial masses, chemical properties, and evolutionary stages.

scholarly journals Distance Measurements and Stellar Population Properties via Surface Brightness Fluctuations

2012 ◽  
Vol 29 (4) ◽  
pp. 489-508 ◽  
Author(s):  
Alexander Fritz
Keyword(s):  
Stellar Evolution ◽  
Globular Clusters ◽  
Surface Brightness ◽  
Stellar Population ◽  
Scale Up ◽  
Asymptotic Giant Branch ◽  
Horizontal Branch ◽  
Stellar Content ◽  
Distance Measurements ◽  
Surface Brightness Fluctuations

AbstractSurface Brightness Fluctuations (SBFs) are one of the most powerful techniques to measure the distance and to constrain the unresolved stellar content of extragalactic systems. For a given bandpass, the absolute SBF magnitude M depends on the properties of the underlying stellar population. Multi-band SBFs allow scientists to probe different stages of the stellar evolution: ultraviolet and blue wavelength band SBFs are sensitive to the evolution of stars within the hot horizontal branch and post-asymptotic giant branch phases, whereas optical SBF magnitudes explore the stars within the red giant branch and horizontal branch regimes. Near- and far-infrared SBF luminosities probe the important stellar evolution stage within the asymptotic giant branch and thermally pulsating asymptotic giant branch phases. Since the first successful application by Tonry and Schneider, a multiplicity of works have used this method to expand the distance scale up to 150 Mpc and beyond. This article gives a historical background of distance measurements, reviews the basic concepts of the SBF technique, presents a broad sample of investigations and discusses possible selection effects, biases, and limitations of the method. In particular, exciting new developments and improvements in the field of stellar population synthesis are discussed that are essential to understand the physics and properties of the populations in unresolved stellar systems. Further, promising future directions of the SBF technique are presented. With new upcoming space-based satellites such as Gaia, the SBF method will remain as one of the most important tools to derive distances to galaxies with unprecedented accuracy and to give detailed insights into the stellar content of globular clusters and galaxies.

scholarly journals Post-AGB Discs from Common-Envelope Evolution

Galaxies ◽  
2018 ◽  
Vol 6 (3) ◽  
pp. 97 ◽  
Author(s):  
Robert Izzard ◽  
Adam Jermyn
Keyword(s):  
Stellar Population ◽  
Asymptotic Giant Branch ◽  
Agb Stars ◽  
Population Synthesis ◽  
Common Envelope ◽  
Disc Model ◽  
Type Interaction ◽  
Orbital Periods ◽  
The Impact ◽  
Disc Formation

Post-asymptotic giant branch (post-AGB) stars with discs are all binaries. Many of these binaries have orbital periods between 100 and 1000 days so cannot have avoided mass transfer between the AGB star and its companion, likely through a common-envelope type interaction. We report on preliminary results of our project to model circumbinary discs around post-AGB stars using our binary population synthesis code binary_c. We combine a simple analytic thin-disc model with binary stellar evolution to estimate the impact of the disc on the binary, and vice versa, fast enough that we can model stellar population and hence explore the rather uncertain parameter space involved with disc formation. We find that, provided the discs form with sufficient mass and angular momentum, and have an inner edge that is relatively close to the binary, they can both prolong the life of their parent post-AGB star and pump the eccentricity of orbits of their inner binaries.

scholarly journals Primordial binary evolution and blue stragglers

2009 ◽  
Vol 5 (S266) ◽  
pp. 333-338 ◽  
Author(s):  
Xuefei Chen ◽  
Zhanwen Han
Keyword(s):  
Stellar Evolution ◽  
Stellar Population ◽  
Spectral Energy Distribution ◽  
Spectral Energy ◽  
Population Synthesis ◽  
Blue Stragglers ◽  
Stellar Population Synthesis ◽  
Magnitude Diagram ◽  
Specific Frequency ◽  
Binary Evolution

AbstractBlue stragglers have been found in all populations. They are important in both stellar evolution and stellar population synthesis. Much evidence shows that blue stragglers are relevant to primordial binaries. Here, we summarize the links between binary evolution and blue stragglers, describe the characteristics of blue stragglers originating from different binary evolutionary channels and show their consequences for binary population synthesis, such as for the integrated spectral-energy distribution, the colour–magnitude diagram, their specific frequency, and their influence on colours, etc.

Stellar Population Synthesis in AGN Host Galaxies

2001 ◽  
Vol 1 ◽  
pp. 145-152
Author(s):  
M. Joly ◽  
C. Boisson ◽  
J. Moultaka ◽  
D. Pelat
Keyword(s):  
Stellar Population ◽  
Population Synthesis ◽  
Host Galaxies ◽  
Stellar Population Synthesis

scholarly journals New models for the rapid evolution of the central star of the Stingray Nebula

2021 ◽  
Author(s):  
T M Lawlor
Keyword(s):  
Mass Loss ◽  
Stellar Evolution ◽  
Planetary Nebula ◽  
Rapid Evolution ◽  
Central Star ◽  
Asymptotic Giant Branch ◽  
Initial Mass ◽  
Thermal Pulse ◽  
The Past ◽  
New Models

Abstract We present stellar evolution calculations from the Asymptotic Giant Branch (AGB) to the Planetary Nebula (PN) phase for models of initial mass 1.2 M⊙ and 2.0 M⊙ that experience a Late Thermal Pulse (LTP), a helium shell flash that occurs following the AGB and causes a rapid looping evolution between the AGB and PN phase. We use these models to make comparisons to the central star of the Stingray Nebula, V839 Ara (SAO 244567). The central star has been observed to be rapidly evolving (heating) over the last 50 to 60 years and rapidly dimming over the past 20–30 years. It has been reported to belong to the youngest known planetary nebula, now rapidly fading in brightness. In this paper we show that the observed timescales, sudden dimming, and increasing Log(g), can all be explained by LTP models of a specific variety. We provide a possible explanation for the nebular ionization, the 1980’s sudden mass loss episode, the sudden decline in mass loss, and the nebular recombination and fading.

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