J/ApJ/640/L43 Metallicities of RR Lyrae stars in Omega Cen (Sollima+, 2006)
New metallicities of RR Lyrae stars in ω Centauri: evidence for a
non-He-enhanced metal-intermediate population.
Sollima A., Borissova J., Catelan M., Smith H.A., Minniti D., Cacciari C.,
Ferraro F.R.
<Astrophys. J., 640, L43-L46 (2006)>
=2006ApJ...640L..43S 2006ApJ...640L..43S
ADC_Keywords: Clusters, globular ; Stars, variable ; Abundances, [Fe/H]
Keywords: globular clusters: individual (ω Centauri) - stars: abundances -
stars: Population II - techniques: spectroscopic
Abstract:
We present new spectroscopic metal abundances for 74 RR Lyrae (RRL)
stars in ω Cen obtained with FLAMES. The well-known metallicity
spread is visible among the RRL variables. The metal-intermediate (MI)
RRL stars ([Fe/H]~-1.2) are fainter than the bulk of the dominant
metal-poor population ([Fe/H]~-1.7), in good agreement with the
corresponding zero-age horizontal-branch models with cosmological
helium abundance Y=0.246.
Description:
Observations of 74 RRL variables (38 RRab and 36 RRc) were collected
on 2005 February and March at the VLT-UT2 at ESO (Cerro Paranal,
Chile) with the multifiber spectrograph FLAMES/MEDUSA.
Objects:
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RA (2000) DE Designation(s)
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13 26 45.9 -47 28 37 ω Cen = NGC 5139
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File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table1.dat 53 74 Metallicities and properties of the target RRLyrae
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See also:
J/A+A/424/1101 : Variable Stars in the field of ω Cen (Kaluzny+, 2004)
J/A+A/420/173 : JK photometry of Omega Cen red giants (Sollima+, 2004)
Byte-by-byte Description of file: table1.dat
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Bytes Format Units Label Explanations
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1- 3 I3 --- Seq The OGLE number
(Cl* NGC 5139 SAW VNNN in Simbad)
5- 9 F5.2 [Sun] [Fe/H] Metallicity
11- 14 F4.2 [Sun] e_[Fe/H] Error in [Fe/H]
16- 21 F6.3 mag Vmag Mean V magnitude from Kaluzny et al.
(2004, Cat. J/A+A/424/1101)
23- 28 F6.3 mag Kmag Mean K magnitude from Sollima et al.
(2004, Cat. J/A+A/420/173)
30- 34 F5.3 [K] log(T) Logarithm of the mean temperature
36- 40 F5.3 [solLum] log(L) Logarithm of the mean luminosity
in solar units
42 I1 --- RRt The RR type: 1=RRab, 0=RRc
44- 47 F4.2 d Vamp The V band amplitude
49- 53 F5.3 d Per Period
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History:
From electronic version of the journal
(End) Greg Schwarz [AAS], Marianne Brouty [CDS] 21-Mar-2007