II/180 uvby-beta photometry of metal-poor stars (Schuster+ 1989)
uvby-beta photometry of high-Velocity and metal-poor stars
Schuster W.J., Nissen P.E.
<Astron. Astrophys. 222, 69 (1989)>
=1989A&A...222...69S 1989A&A...222...69S
ADC_Keywords: Stars, high-velocity ; Stars, metal-deficient
Keywords: evolution of the Galaxy - halo stars - metallicity - ages
Description:
Using the calibrations derived by Schuster and Nissen
(=1989A&A...221...65S 1989A&A...221...65S), the interstellar color excesses, E(b-y), and
the metallicities, [Fe/H], have been determined for the 711 high
velocity and metal-poor stars in the catalogue of uvby-beta photometry
(=1988A&AS...73..225S 1988A&AS...73..225S). 220 of these listed in table1 turn out to be
halo stars according to the criterion [Fe/H] ≤ -1.0. About 15% of
the halo stars have colors that are significantly affected by
interstellar reddening, i.e. E(b-y) > 0.025.
The distributions in the c0-(b-y)0 diagram of the halo stars grouped
according to [Fe/H], have well defined turn-off points. From the Teff
values of these points a minimum age of 18-20 Gyr for the halo stars
is determined. However, this age may be 2-3 Gyr too high due to a
possible systematic error in Teff for the stellar models used.
Relative ages of 77 halo stars in the turn-off region of the c0-(b-y)0
diagram are derived using the isochrones VandenBerg and Bell
(=1985ApJS...58..561V 1985ApJS...58..561V). Assuming that the O/Fe abundance ratio is
constant in halo stars, evidence of a cosmic age scatter of
±2.5Gyr at a given metallicity is found. Furthermore, the mean age
of the halo stars is found to decrease smoothly by about 3 Gyr from
[Fe/H]= -2.0 to -1.0. These results suggest that a pressure-supported
slow uniform collapse controlled the formation and early evolution of
the Galaxy. However, the scenario of Searle and Zinn
(=1978ApJ...225..357S 1978ApJ...225..357S) is also compatible with the results.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table1 73 220 The Catalogue
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See also:
J/A+AS/97/951 : Metal-poor stars uvby-beta photometry. VI. (Schuster+, 1993)
J/A+AS/117/317 : Metal-poor stars uvby-beta photometry. VIII. (Schuster+, 1996)
J/A+A/422/527 : Metal-poor stars uvby-beta photometry. X. (Schuster+, 2004)
J/A+A/445/939 : Metal-poor stars uvby-beta photometry. XI. (Schuster+, 2006)
Byte-per-byte Description of file: table1
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Bytes Format Units Label Explanations
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3- 12 A10 --- Name Star designation (HD/DM/Giclas)
15- 16 I2 h RAh Right Ascension 1950
18- 19 I2 min RAm Right Ascension 1950
21- 24 F4.1 s RAs Right Ascension 1950
27 A1 --- DE- Declination 1950 Sign
28- 29 I2 deg DEd Declination 1950
31- 32 I2 arcmin DEm Declination 1950
34- 35 I2 arcsec DEs Declination 1950
38- 43 F6.3 mag E(b-y) ? Interstellar reddening
45 A1 --- l_[Fe/H] '<' if [Fe/H] metallicity is an upper limit
46- 50 F5.2 Sun [Fe/H] [-3.5/-1[ Metallicity (relative to Sun)
53- 56 F4.1 Ga Age ? Age in Giga-years
59- 61 F3.1 Ga e_Age ? rms error on Age
64- 73 A10 --- Notes Remarks (1)
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Note (1): the following symbols are used in the remarks:
AGB = asymptotic giant branch
D = two stars in the diaphragm
PHV = photometrically variable
RHB = red horizontal branch
RV-var = radial velocity variable
SB-CL = spectroscopic binary (Carney + Latham, 1987, AJ 93, 116)
SG = subgiant
BS? = possible blue straggler
* See Individual Notes
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Individual Notes:
G 266-060: common proper motion with G 226-061.
HD 23439: double, component B is SB-CL, orbital elements by
Latham et al. (=1988AJ.....96..567L 1988AJ.....96..567L).
G 088-010: orbital elements by Latham et al. (=1988AJ.....96..567L 1988AJ.....96..567L).
G 089-014: orbital elements by Latham et al. (=1988AJ.....96..567L 1988AJ.....96..567L).
G 114-026: orbital elements by Latham et al. (=1988AJ.....96..567L 1988AJ.....96..567L).
HD 103095: double, orbital elements by
Beardsley et al. (=1974ApJ...194..637B 1974ApJ...194..637B).
G 065-022: orbital elements by Latham et al. (=1988AJ.....96..567L 1988AJ.....96..567L).
HD 134439: common proper motion with HD 134440.
G 141-019: orbital elements by Latham et al. (=1988AJ.....96..567L 1988AJ.....96..567L).
G 206-034: orbital elements by Latham et al. (=1988AJ.....96..567L 1988AJ.....96..567L).
G 026-009: double lined SB, orbital elements by
Peterson et al. (=1980ApJ...239...50R 1980ApJ...239...50R).
G 126-062: orbital elements by Latham et al. (=1988AJ.....96..567L 1988AJ.....96..567L).
Acknowledgements:
We thank Dr Poul E. Nissen for having supplied a copy of Table1.
Historical Notes:
* 09-Sep-1992: table supplied by Poul E. Nissen
* 04-Jan-1993: First documentation at CDS (Francois Ochsenbein)
* 03-Nov-1995: Documentation standardized at CDS, and notes added
(Francois Ochsenbein)
References:
Schuster et al., Paper I 1988A&AS...73..225S 1988A&AS...73..225S
Schuster et al., Paper II 1989A&A...221...65S 1989A&A...221...65S
Allen et al., Paper IV 1991A&A...244..280A 1991A&A...244..280A
Nissen et al., Paper V 1991A&A...251..457N 1991A&A...251..457N
Schuster et al. Paper VI 1993A&AS...97..951S 1993A&AS...97..951S, Cat. J/A+AS/97/951
Marquez et al., Paper VII 1994A&AS..108..341M 1994A&AS..108..341M
Schuster et al., Paper VIII 1996A&AS..117..317S 1996A&AS..117..317S, Cat. J/A+AS/117/317
Schuster et al., Paper IX 1997A&A...319..796S 1997A&A...319..796S
Schuster et al., Paper X 2004A&A...422..527S 2004A&A...422..527S, Cat. J/A+A/422/527
Schuster et al., Paper XI 2006A&A...445..939S 2006A&A...445..939S, Cat. J/A+A/445/939
(End) Francois Ochsenbein [CDS] 03-Nov-1995