J/ApJ/647/1075 Age-metallicity relation of ω Cen (Stanford+, 2006)
The age and metallicity relation of ω Centauri.
Stanford L.M., Da Costa G.S., Norris J.E., Cannon R.D.
<Astrophys. J., 647, 1075-1092 (2006)>
=2006ApJ...647.1075S 2006ApJ...647.1075S
ADC_Keywords: Clusters, globular ; Photometry, UBV ; Radial velocities ;
Abundances, [Fe/H]
Keywords: globular clusters: general -
globular clusters: individual (omega Centauri)
Abstract:
We present a metallicity distribution based on photometry and spectra
for 442 Omega Centauri cluster members that lie at the main-sequence
turnoff region of the color-magnitude diagram. This distribution is
similar to that found for the red giant branch. The distribution shows
a sharp rise to a mean of [Fe/H]=-1.7 with a long tail to higher
metallicities. Ages have then been determined for the stars using
theoretical isochrones enabling the construction of an age-metallicity
diagram. Interpretation of this diagram is complicated by the
correlation of the errors in the metallicities and ages. Nevertheless,
after extensive Monte Carlo simulations, we conclude that our data
show that the formation of the cluster took place over an extended
period of time: the most metal-rich stars in our sample ([Fe/H]~-0.6)
are younger by 2-4Gyr than the most metal-poor population.
Description:
Photometry for the cluster was obtained with the 1m telescope +
Tektronix CCD combination at Siding Spring Observatory,
in the V and B bands.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table2.dat 72 410 omega Cen Members
table3.dat 57 565 Non-Members in the 2002 observing box
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See also:
J/MNRAS/250/314 : CCD photometry of omega Cen (Noble+ 1991)
J/PASP/106/828 : BVRI photometry of Omega Cen (Walker 1994)
J/AJ/114/1087 : Omega Cen radial velocities (Mayor+ 1997)
J/AJ/127/958 : CCD BV photometry on Omega Cen (Rey+, 2004)
J/A+A/445/503 : Radial velocities in Omega Cen (NGC5139) (Reijns+, 2006)
J/AJ/135/1395 : omega Cen Spitzer photometry (Boyer+, 2008)
Byte-by-byte Description of file: table2.dat
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Bytes Format Units Label Explanations
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1- 7 I7 --- SDN Object identification number,
CL* NGC 5139 SDN NNNNNNN in Simbad
9- 10 I2 h RAh Hour of Right Ascension (J2000)
12- 13 I2 min RAm Minute of Right Ascension (J2000)
15- 19 F5.2 s RAs Second of Right Ascension (J2000)
21 A1 --- DE- Sign of the Declination (J2000)
22- 23 I2 deg DEd Degree of Declination (J2000)
25- 26 I2 arcmin DEm Arcminute of Declination (J2000)
28- 31 F4.1 arcsec DEs Arcsecond of Declination (J2000)
33- 37 F5.2 mag Vmag The V band magnitude
39- 42 F4.2 mag B-V The (B-V) color index
44- 46 I3 km/s HRV Heliocentic radial velocity
48- 53 F6.2 [-] [Fe/H] The [Fe/H] abundance
55- 58 F4.2 [-] e_[Fe/H] The 1σ error in [Fe/H]
60- 63 F4.1 Gyr Age Stellar Age
65- 68 F4.1 Gyr e_Age The 1σ error in Age
70- 72 A3 --- Run Observation run (1=1998/1999, 2=2002)
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Byte-by-byte Description of file: table3.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 7 I7 --- SDN Object identification number,
CL* NGC 5139 SDN NNNNNNN in Simbad
9- 10 I2 h RAh Hour of Right Ascension (J2000)
12- 13 I2 min RAm Minute of Right Ascension (J2000)
15- 19 F5.2 s RAs Second of Right Ascension (J2000)
21 A1 --- DE- Sign of the Declination (J2000)
22- 23 I2 deg DEd Degree of Declination (J2000)
25- 26 I2 arcmin DEm Arcminute of Declination (J2000)
28- 32 F5.2 arcsec DEs Arcsecond of Declination (J2000)
34- 39 F6.3 mag Vmag The V band magnitude
41- 45 F5.3 mag B-V The (B-V) color index
47- 53 F7.2 km/s HRV Heliocentic radial velocity
55- 57 A3 --- Run Observation run (1=1998/1999, 2=2002)
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History:
From electronic version of the journal
(End) Greg Schwarz [AAS], Patricia Vannier [CDS] 11-Jul-2008