An overview of the rotational bechavior of metal-poor stars

This paper describes the behavior of the rotational velocity in metal-poor stars ([Fe/H] ≤ –0.5 dex) in different evolutionary stages, based on vsin i values from the literature. Our sample is comprised of stars in the field and some Galactic globular clusters, including stars on the main sequence,...

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Principais autores: Cortes, C., Silva, J. R. P., Recio-Blanco, A., Catelan, M., Nascimento Junior, Jose Dias do, Medeiros, José Renan de
Formato: article
Idioma:English
Publicado em: Sociedade Astronômica Americana
Assuntos:
Stars - evolution
Fundamental parameters – stars
Stars - statistics
Stars - rotation
Acesso em linha:https://repositorio.ufrn.br/jspui/handle/123456789/29115
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spelling ri-123456789-291152022-10-20T20:09:58Z An overview of the rotational bechavior of metal-poor stars Cortes, C. Silva, J. R. P. Recio-Blanco, A. Catelan, M. Nascimento Junior, Jose Dias do Medeiros, José Renan de Stars - evolution Fundamental parameters – stars Stars - statistics Stars - rotation This paper describes the behavior of the rotational velocity in metal-poor stars ([Fe/H] ≤ –0.5 dex) in different evolutionary stages, based on vsin i values from the literature. Our sample is comprised of stars in the field and some Galactic globular clusters, including stars on the main sequence, the red giant branch (RGB), and the horizontal branch (HB). The metal-poor stars are, mainly, slow rotators, and their vsin i distribution along the HR diagram is quite homogeneous. Nevertheless, a few moderate to high values of vsin i are found in stars located on the main sequence and the HB. We show that the overall distribution of vsin i values is basically independent of metallicity for the stars in our sample. In particular, the fast-rotating main sequence stars in our sample present rotation rates similar to their metal-rich counterparts, suggesting that some of them may actually be fairly young, in spite of their low metallicity, or else that at least some of them would be better classified as blue straggler stars. We do not find significant evidence of evolution in vsin i values as a function of position on the RGB; in particular, we do not confirm previous suggestions that stars close to the RGB tip rotate faster than their less-evolved counterparts. While the presence of fast rotators among moderately cool blue HB stars has been suggested to be due to angular momentum transport from a stellar core that has retained significant angular momentum during its prior evolution, we find that any such transport mechanisms most likely operate very fast as the star arrives on the zero-age HB (ZAHB), since we do not find a link between evolution off the ZAHB and vsin i values. We present an extensive tabulation of all quantities discussed in this paper, including rotation velocities, temperatures, gravities, and metallicities [Fe/H], as well as broadband magnitudes and colors. 2020-06-01T02:23:22Z 2020-06-01T02:23:22Z 2009 article CORTÉS, C. ; SILVA, J. R. P. ; RECIO-BLANCO, A. ; CATELAN, M. ; NASCIMENTO JUNIOR, J. D. ; MEDEIROS, J. R. de. An overview of the rotational bechavior of metal-poor stars. The Astrophysical Journal, v. 704, p. 750-769, 2009. Disponível em: http://iopscience.iop.org/article/10.1088/0004-637X/704/1/750/meta. Acesso em: 18 Maio 2020. http://dx.doi.org/10.1088/0004-637X/704/1/750 https://repositorio.ufrn.br/jspui/handle/123456789/29115 10.1088/0004-637X/704/1/750 en Sociedade Astronômica Americana
institution Repositório Institucional
collection RI - UFRN
language English
topic Stars - evolution
Fundamental parameters – stars
Stars - statistics
Stars - rotation
spellingShingle Stars - evolution
Fundamental parameters – stars
Stars - statistics
Stars - rotation
Cortes, C.
Silva, J. R. P.
Recio-Blanco, A.
Catelan, M.
Nascimento Junior, Jose Dias do
Medeiros, José Renan de
An overview of the rotational bechavior of metal-poor stars
description This paper describes the behavior of the rotational velocity in metal-poor stars ([Fe/H] ≤ –0.5 dex) in different evolutionary stages, based on vsin i values from the literature. Our sample is comprised of stars in the field and some Galactic globular clusters, including stars on the main sequence, the red giant branch (RGB), and the horizontal branch (HB). The metal-poor stars are, mainly, slow rotators, and their vsin i distribution along the HR diagram is quite homogeneous. Nevertheless, a few moderate to high values of vsin i are found in stars located on the main sequence and the HB. We show that the overall distribution of vsin i values is basically independent of metallicity for the stars in our sample. In particular, the fast-rotating main sequence stars in our sample present rotation rates similar to their metal-rich counterparts, suggesting that some of them may actually be fairly young, in spite of their low metallicity, or else that at least some of them would be better classified as blue straggler stars. We do not find significant evidence of evolution in vsin i values as a function of position on the RGB; in particular, we do not confirm previous suggestions that stars close to the RGB tip rotate faster than their less-evolved counterparts. While the presence of fast rotators among moderately cool blue HB stars has been suggested to be due to angular momentum transport from a stellar core that has retained significant angular momentum during its prior evolution, we find that any such transport mechanisms most likely operate very fast as the star arrives on the zero-age HB (ZAHB), since we do not find a link between evolution off the ZAHB and vsin i values. We present an extensive tabulation of all quantities discussed in this paper, including rotation velocities, temperatures, gravities, and metallicities [Fe/H], as well as broadband magnitudes and colors.
format article
author Cortes, C.
Silva, J. R. P.
Recio-Blanco, A.
Catelan, M.
Nascimento Junior, Jose Dias do
Medeiros, José Renan de
author_facet Cortes, C.
Silva, J. R. P.
Recio-Blanco, A.
Catelan, M.
Nascimento Junior, Jose Dias do
Medeiros, José Renan de
author_sort Cortes, C.
title An overview of the rotational bechavior of metal-poor stars
title_short An overview of the rotational bechavior of metal-poor stars
title_full An overview of the rotational bechavior of metal-poor stars
title_fullStr An overview of the rotational bechavior of metal-poor stars
title_full_unstemmed An overview of the rotational bechavior of metal-poor stars
title_sort overview of the rotational bechavior of metal-poor stars
publisher Sociedade Astronômica Americana
publishDate 2020
url https://repositorio.ufrn.br/jspui/handle/123456789/29115
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