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On metal-deficient barium stars and their link with yellow symbiotic stars

Jorissen, A; Zacs, L; Udry, S; Lindgren, Harri LU and Musaev, FA (2005) In Astronomy & Astrophysics 441(3). p.83-1135
Abstract
This paper addresses the question of why metal- deficient barium stars are not yellow symbiotic stars ( YSyS). Samples of ( suspected) metal-deficient barium ( mdBa) stars and YSyS have been collected from the literature, and their properties reviewed. It appears in particular that the barium nature of the suspected mdBa stars needs to be ascertained by detailed abundance analyses. Abundances are therefore derived for two of them, HD 139409 and HD 148897, which reveal that HD 148897 should not be considered a barium star. HD 139409 is a mild barium star, with overabundances observed only for elements belonging to the first s- process peak ( Y and Zr). It is only moderately metal- poor ([ Fe/ H] = - 0.4). The evidence for binarity among... (More)
This paper addresses the question of why metal- deficient barium stars are not yellow symbiotic stars ( YSyS). Samples of ( suspected) metal-deficient barium ( mdBa) stars and YSyS have been collected from the literature, and their properties reviewed. It appears in particular that the barium nature of the suspected mdBa stars needs to be ascertained by detailed abundance analyses. Abundances are therefore derived for two of them, HD 139409 and HD 148897, which reveal that HD 148897 should not be considered a barium star. HD 139409 is a mild barium star, with overabundances observed only for elements belonging to the first s- process peak ( Y and Zr). It is only moderately metal- poor ([ Fe/ H] = - 0.4). The evidence for binarity among mdBa stars is then reviewed, using three different methods: ( i) radial- velocity variations ( from CORAVEL observations), ( ii) Hipparcos astrometric data, and ( iii) a method based on the comparison between the Hipparcos and Tycho- 2 proper motions. An orbit is obtained for HIP 55852, whereas evidence for the ( so far unknown) binary nature of HIP 34795, HIP 76605, HIP 97874 and HIP 107478 is presented. No conclusion regarding the binary nature of HIP 11595, HIP 25161 could be reached. Two stars with no evidence for binarity whatsoever ( HIP 58596 and BD + 3. 2688) are candidates low- metallicity thermally- pulsing asymptotic giant branch stars, as inferred from their large luminosities. The reason why mdBa stars are not YSyS is suggested to lie in their different orbital period distributions: mdBa stars have on average longer orbital periods than YSyS, and hence their companion accretes matter at a lower rate, for a given mass loss rate of the giant star. The definite validation of this explanation should nevertheless await the determination of the orbital periods for the many mdBa stars still lacking periods, in order to make the comparison more significant. (Less)
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author
organization
publishing date
type
Contribution to journal
publication status
published
subject
keywords
stars : abundances, stars : AGB and post-AGB, binaries : symbiotic, binaries : spectroscopic
in
Astronomy & Astrophysics
volume
441
issue
3
pages
83 - 1135
publisher
EDP Sciences
external identifiers
  • wos:000232071600028
  • scopus:26844485096
ISSN
0004-6361
language
English
LU publication?
yes
id
2d0b8315-ae44-423e-998b-f871edfb2fa2 (old id 223521)
date added to LUP
2007-08-20 17:03:10
date last changed
2017-01-01 07:00:28
@article{2d0b8315-ae44-423e-998b-f871edfb2fa2,
  abstract     = {This paper addresses the question of why metal- deficient barium stars are not yellow symbiotic stars ( YSyS). Samples of ( suspected) metal-deficient barium ( mdBa) stars and YSyS have been collected from the literature, and their properties reviewed. It appears in particular that the barium nature of the suspected mdBa stars needs to be ascertained by detailed abundance analyses. Abundances are therefore derived for two of them, HD 139409 and HD 148897, which reveal that HD 148897 should not be considered a barium star. HD 139409 is a mild barium star, with overabundances observed only for elements belonging to the first s- process peak ( Y and Zr). It is only moderately metal- poor ([ Fe/ H] = - 0.4). The evidence for binarity among mdBa stars is then reviewed, using three different methods: ( i) radial- velocity variations ( from CORAVEL observations), ( ii) Hipparcos astrometric data, and ( iii) a method based on the comparison between the Hipparcos and Tycho- 2 proper motions. An orbit is obtained for HIP 55852, whereas evidence for the ( so far unknown) binary nature of HIP 34795, HIP 76605, HIP 97874 and HIP 107478 is presented. No conclusion regarding the binary nature of HIP 11595, HIP 25161 could be reached. Two stars with no evidence for binarity whatsoever ( HIP 58596 and BD + 3. 2688) are candidates low- metallicity thermally- pulsing asymptotic giant branch stars, as inferred from their large luminosities. The reason why mdBa stars are not YSyS is suggested to lie in their different orbital period distributions: mdBa stars have on average longer orbital periods than YSyS, and hence their companion accretes matter at a lower rate, for a given mass loss rate of the giant star. The definite validation of this explanation should nevertheless await the determination of the orbital periods for the many mdBa stars still lacking periods, in order to make the comparison more significant.},
  author       = {Jorissen, A and Zacs, L and Udry, S and Lindgren, Harri and Musaev, FA},
  issn         = {0004-6361},
  keyword      = {stars : abundances,stars : AGB and post-AGB,binaries : symbiotic,binaries : spectroscopic},
  language     = {eng},
  number       = {3},
  pages        = {83--1135},
  publisher    = {EDP Sciences},
  series       = {Astronomy & Astrophysics},
  title        = {On metal-deficient barium stars and their link with yellow symbiotic stars},
  volume       = {441},
  year         = {2005},
}