J/AJ/90/2089 Stars of very low metal abundance. I (Beers+, 1985)
A search for stars of very low metal abundance. I
Beers T.C., Preston G.W., Shectman S.A.
<Astron. J. 90, 2089 (1985)>
=1985AJ.....90.2089B 1985AJ.....90.2089B
ADC_Keywords: Stars, metal-deficient ; Stars, halo ; Spectroscopy
Description:
An objective-prism and a narrowband interference filter have been used
in combination on the Curtis Schmidt telescope at CTIO to conduct a
search for extremely metal-poor stars. The filter restricts the
bandpass to the region around the H and K lines of CaII; the
metal-poor candidates are those stars with weak or absent H and K.
Slit spectra (1 A resolution) of some 450 candidates are used to
measure equivalent widths of the CaII K line and Balmer features.
A calibration of the K-line strength for giants in the metal-poor
globular cluster NGC 6397 and field dwarfs and giants of known
metallicity is used to identify survey candidates with metal abundance
[Fe/H]≤-2.0; a list of 134 such stars is presented. UBV photometry is
used to distinguish between two groups of metal-poor stars: a group
with objects near the main-sequence turnoff, on the subgiant branch,
and on the giant branch; and a second group with objects on the red
horizontal branch (RHB) and asymptotic giant branch (AGB). The RHB-AGB
stars exhibit the well-known weak G-band effect; three CH-strong
objects are identified among the subgiants.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table1.dat 43 72 Objective-prism survey plate log
table3.dat 30 13 Velocities of standard stars
table4.dat 67 32 Standard-star line indices
table5.dat 110 134 Metal-poor stars
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See also:
J/AJ/87/1515 : UBV photometry of AB stars in halo (Pier, 1982)
J/ApJS/53/791 : Spectroscopy of AB stars in halo (Pier, 1983)
J/PASP/102/1392 : UBV photometry from HK survey. (Doinidis+ 1990)
J/PASP/103/973 : Photoelectric UBV from HK survey. (Doidinis+ 1991)
J/ApJS/76/1001 : UBV photometry of HK survey stars (Preston+, 1991)
J/AJ/103/267 : Spectrocopy of hot stars in galactic halo (Beers+ 1992)
J/AJ/103/1987 : Stars of very low metal abundance (Beers+ 1992)
J/AJ/108/268 : HK survey emission-line candidates positions (Beers+ 1994)
J/AJ/108/538 : Metal-poor MS stars UBV photometry (Preston+ 1994)
J/AJ/112/1188 : HK survey emission-line candidates (Beers+ 1996)
J/AJ/117/2329 : Spectroscopy of hot stars in the halo. (Wilhelm+, 1999)
J/ApJS/123/639 : UBV photometry of metal-weak candidates (Norris+, 1999)
Byte-by-byte Description of file: table1.dat
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Bytes Format Units Label Explanations
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2- 6 I5 --- BPS-CS Plate number (Curtis Schmidt)
16- 17 I2 h RAh Right ascension (1950)
19- 22 F4.1 min RAm Right ascension (1950)
24 A1 --- DE- Declination sign
25- 26 I2 deg DEd Declination (1950)
28- 29 I2 arcmin DEm Declination (1950)
32- 36 F5.1 deg GLON Galactic longitude
39- 43 F5.1 deg GLAT Galactic latitude
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Byte-by-byte Description of file: table3.dat
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Bytes Format Units Label Explanations
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1- 10 A10 --- Star Star
13- 16 I4 km/s RVcat Radial velocity from Carney
(1981ApJ...245..238C 1981ApJ...245..238C)
19- 22 I4 km/s RVobs Observed radial velocity
24- 25 I2 km/s e_RVobs Error on radial velocity
28- 30 I3 km/s DRV Difference between the observed and
taken from literature radial velocity
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Byte-by-byte Description of file: table4.dat
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Bytes Format Units Label Explanations
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1- 13 A13 --- Star Star name
17- 20 F4.2 0.1nm EW(K) CaII K-line index (G1)
23- 25 F3.2 0.1nm e_EW(K) ? Error on K index
28- 31 F4.2 0.1nm EW(H') H' line index (G1)
34- 36 F3.2 0.1nm e_EW(H') ? Error on H'
39- 42 F4.2 0.1nm EW(G) G-band line index (G1)
45- 47 F3.2 0.1nm e_EW(G) ? Error on G
50- 53 F4.2 mag B-V B-V colour index
55- 58 F4.1 Sun [Fe/H] Metallicity [Fe/H]
61 A1 --- LC [dg] luminosity lass: 'g' (giant) when the
star lies above the main-sequence turnoff,
'd' (dwarf) when the star lies below
the main-sequence turnoff
64- 67 A4 --- Refs References (2)
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Note (2): The references are numbered as follows:
1 = Bessell and Norris 1984ApJ...285..622B 1984ApJ...285..622B
2 = Bond 1970ApJS...22..117B 1970ApJS...22..117B
3 = Cannon 1974MNRAS.167..551C 1974MNRAS.167..551C
4 = Carney 1979ApJ...233..211C 1979ApJ...233..211C
5 = Carney 1980AJ.....85...38C 1980AJ.....85...38C
6 = Carney and Peterson 1981ApJ...245..238C 1981ApJ...245..238C
7 = Sneden 1974ApJ...189..493S 1974ApJ...189..493S
8 = Spite and Spite 1978A&A....67...23S 1978A&A....67...23S
9 = Wallerstein et.al. 1963ApJ...137..280W 1963ApJ...137..280W
10 = Zinn 1980ApJS...42...19Z 1980ApJS...42...19Z
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Byte-by-byte Description of file: table5.dat
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Bytes Format Units Label Explanations
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1- 9 A9 --- BPS-CS Metal poor candidate star name
11- 12 I2 h RAh Right ascension (1950)
14- 15 I2 min RAm Right ascension (1950)
17- 20 F4.1 s RAs Right ascension (1950)
22 A1 --- DE- Declination sign
23- 24 I2 deg DEd Declination (1950)
26- 27 I2 arcmin DEm Declination (1950)
29- 30 I2 arcsec DEs Declination (1950)
32- 36 F5.1 deg GLON Galactic longitude
38- 42 F5.1 deg GLAT Galactic latitude
44- 47 I4 km/s HV Heliocentric velocity
49- 50 I2 km/s e_HV Error on heliocentric velocity
54- 58 F5.2 mag Vmag Johnson V magnitude
61- 64 F4.2 mag B-V Johnson (B-V) color
66- 70 F5.2 mag U-B Johnson (U-B) color
74 I1 --- Nobs Number of photometric observations
76- 79 F4.2 mag E(B-V) ? Assumed reddening
82- 85 F4.2 0.1nm EW(K) CaII K-line index (G1)
87- 90 F4.2 0.1nm e_EW(K) Error on CaII K-line index
92- 95 F4.2 0.1nm EW(H') H' line index (G1)
97-100 F4.2 0.1nm e_EW(H') Error on H' index
101-105 F5.2 0.1nm EW(G) G-band line index (G1)
107-110 F4.2 0.1nm e_EW(G) Error on G-band line index
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Global notes:
Note (G1): Line-index wavelength bands (Table 2, ranges in Å=0.1nm)
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Line Band Blue sideband Red sideband
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CaII K 3927.7-3939.7 3903.9-3923.9 4008.0-4028.0
Hdelta 4098.8-4104.8 4008.0-4028.0 4144.0-4164.0
G-band 4297.5-4312.5 4247.0-4267.0 4357.0-4377.0
Hgamma 4337.5-4343.5 4247.0-4267.0 4357.0-4377.0
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H' is defined as 0.5 Hδ + 0.525 Hγ - 0.05
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References:
Beers et al., Paper II, 1992AJ....103.1987B 1992AJ....103.1987B, Cat. J/AJ/103/1987
Norris et al., Paper III, 1999ApJS..123..639N 1999ApJS..123..639N, Cat. J/ApJS/123/639
Anthony-Twarog et al., Paper IV, 2000AJ....119.2882A 2000AJ....119.2882A
Bonifacio et al., Paper V, 2000AJ....120.2065B 2000AJ....120.2065B
Roederer et al., Paper VI, 2014AJ....147..136R 2014AJ....147..136R, Cat. J/AJ/147/136
Beers T.C., Preston G.W., Shectman S.A. 1992, Astron. Journal 103, 1987
Bessell M.S., Norris J. 1984, Astrophys. J. 285, 622
Bond H.E. 1970, Astrophys. J. Suppl. 22, 117
Cannon R.D. 1974, MNRAS 167, 551
Carney B.W. 1979, Astrophys. J., 233, 211
Carney B.W. 1980a, Astron. J. 85, 38
Carney B.W. 1980b, "A Catalog of Field Population II Stars" (preprint)
Carney B.W., Peterson R.C. 1981, Astrophys. J., 245, 238
Sneden C. 1974, Astrophys. J., 189, 493
Spite M., Spite F. 1978, Astron. Astrophys., 67, 23
Wallerstein G., Greenstein J.L., Parker R., Helfer H.L., Aller L.H. 1963,
Astrophys. J., 137, 280
Zinn R.J. 1980, Astrophys. J., Suppl., 42, 19
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Historical Notes: Keypunched at CDS
(End) James Marcout, Simona Mei [CDS] 14-Aug-1995