A Brief Introduction to Stellar Evolution

With the aim of providing a reference frame for the study of stellar pulsations we describe the process known as stellar evolution. Evolution and pulsations are deeply related and the knowledge gained in one of them has an immediate impact on the other. First we describe the observational basis, pre...

Descripción completa

Detalles Bibliográficos
Autor principal: Benvenuto, Omar Gustavo
Formato: Objeto de conferencia
Lenguaje:Inglés
Publicado: 2019
Materias:
Ciencias Astronómicas
stars: evolution
stars: interiors
Acceso en línea:http://sedici.unlp.edu.ar/handle/10915/167717
Aporte de:
SEDICI (UNLP) de Universidad Nacional de La Plata
id I19-R120-10915-167717
record_format dspace
spelling I19-R120-10915-1677172024-07-03T20:02:09Z http://sedici.unlp.edu.ar/handle/10915/167717 A Brief Introduction to Stellar Evolution Benvenuto, Omar Gustavo 2019-11 2021 2024-07-03T13:42:01Z en Ciencias Astronómicas stars: evolution stars: interiors With the aim of providing a reference frame for the study of stellar pulsations we describe the process known as stellar evolution. Evolution and pulsations are deeply related and the knowledge gained in one of them has an immediate impact on the other. First we describe the observational basis, presenting the Hertzsprung-Russell Diagram and other fundamental concepts. Then we describe the physical context of stellar evolution in which, quite fortunately, matter is very close to (but not in) thermodynamic equilibrium. This allows for a simplification of the problem of paramount importance. We describe the equation of state of stellar matter, paying attention on when we should expect the occurrence of partial and full ionization (fundamental for pulsations), and electron degeneracy. Then, we present the concept of hydrostatic equilibrium. As a natural consequence we consider barotropic structures, like polytropic spheres and cold white dwarfs, discussing the existence of the Chandrasekhar’s mass limit. As realistic stars are not cold but at finite temperature (they radiate energy in space!), in general they are nonbarotropic. So, we need to consider the conservation of energy and also its transport by radiation, convection and conduction. As it is well known, the engine of stars is nuclear reactions. We present the proton-proton and carbon-nitrogen-oxygen cycles of hydrogen burning and also the main helium burning reactions. Then, we make some brief comments on the methods for solving the full set of non-linear, partial differential equations of stellar evolution and also those needed for computing the changes of chemical composition. At this point we are in conditions to present stellar evolution as a direct consequence of these physical ingredients. We discuss the main stages of stellar evolution for a variety of objects: pre-main sequence, low and intermediate mass, white dwarfs, and finally massive stars. In this paper we restricted ourselves to the case of isolated and nonrotating objects evolving during their long lived stages. In our opinion, this provides a general basis for most of the usually considered pulsating stars. Instituto de Astrofísica de La Plata Facultad de Ciencias Astronómicas y Geofísicas Objeto de conferencia Objeto de conferencia http://creativecommons.org/licenses/by-nc-sa/4.0/ Creative Commons Attribution-NonCommercial-ShareAlike 4.0 International (CC BY-NC-SA 4.0) application/pdf 3-44
institution Universidad Nacional de La Plata
institution_str I-19
repository_str R-120
collection SEDICI (UNLP)
language Inglés
topic Ciencias Astronómicas
stars: evolution
stars: interiors
spellingShingle Ciencias Astronómicas
stars: evolution
stars: interiors
Benvenuto, Omar Gustavo
A Brief Introduction to Stellar Evolution
topic_facet Ciencias Astronómicas
stars: evolution
stars: interiors
description With the aim of providing a reference frame for the study of stellar pulsations we describe the process known as stellar evolution. Evolution and pulsations are deeply related and the knowledge gained in one of them has an immediate impact on the other. First we describe the observational basis, presenting the Hertzsprung-Russell Diagram and other fundamental concepts. Then we describe the physical context of stellar evolution in which, quite fortunately, matter is very close to (but not in) thermodynamic equilibrium. This allows for a simplification of the problem of paramount importance. We describe the equation of state of stellar matter, paying attention on when we should expect the occurrence of partial and full ionization (fundamental for pulsations), and electron degeneracy. Then, we present the concept of hydrostatic equilibrium. As a natural consequence we consider barotropic structures, like polytropic spheres and cold white dwarfs, discussing the existence of the Chandrasekhar’s mass limit. As realistic stars are not cold but at finite temperature (they radiate energy in space!), in general they are nonbarotropic. So, we need to consider the conservation of energy and also its transport by radiation, convection and conduction. As it is well known, the engine of stars is nuclear reactions. We present the proton-proton and carbon-nitrogen-oxygen cycles of hydrogen burning and also the main helium burning reactions. Then, we make some brief comments on the methods for solving the full set of non-linear, partial differential equations of stellar evolution and also those needed for computing the changes of chemical composition. At this point we are in conditions to present stellar evolution as a direct consequence of these physical ingredients. We discuss the main stages of stellar evolution for a variety of objects: pre-main sequence, low and intermediate mass, white dwarfs, and finally massive stars. In this paper we restricted ourselves to the case of isolated and nonrotating objects evolving during their long lived stages. In our opinion, this provides a general basis for most of the usually considered pulsating stars.
format Objeto de conferencia
Objeto de conferencia
author Benvenuto, Omar Gustavo
author_facet Benvenuto, Omar Gustavo
author_sort Benvenuto, Omar Gustavo
title A Brief Introduction to Stellar Evolution
title_short A Brief Introduction to Stellar Evolution
title_full A Brief Introduction to Stellar Evolution
title_fullStr A Brief Introduction to Stellar Evolution
title_full_unstemmed A Brief Introduction to Stellar Evolution
title_sort brief introduction to stellar evolution
publishDate 2019
url http://sedici.unlp.edu.ar/handle/10915/167717
work_keys_str_mv AT benvenutoomargustavo abriefintroductiontostellarevolution
AT benvenutoomargustavo briefintroductiontostellarevolution
_version_ 1807223552784465920

Ejemplares similares