J/MNRAS/433/1892 Abundances of 848 giants of ω Cen (Simpson+, 2013)
Spectral matching for abundances of 848 stars of the giant branches of the
globular cluster ω Centauri.
Simpson J.D., Cottrell P.L.
<Mon. Not. R. Astron. Soc., 433, 1892-1902 (2013)>
=2013MNRAS.433.1892S 2013MNRAS.433.1892S
ADC_Keywords: Clusters, globular ; Stars, giant ; Abundances
Keywords: stars: abundances - stars: AGB and post-AGB -
globular clusters: individual: ω Centauri (NGC 5139)
Abstract:
We present the effective temperatures, surface gravities and
abundances of iron, carbon and barium of 848 giant branch stars, of
which 557 also have well-defined nitrogen abundances, of the globular
cluster ω Centauri. This work used photometric sources and lower
resolution spectra for this abundance analysis. Spectral indices were
used to estimate the oxygen abundance of the stars, leading to a
determination of whether a particular star was oxygen rich or oxygen
poor.
The 557-star subset was analysed in the context of evolutionary
groups, with four broad groups identified. These groups suggest that
there were at least four main periods of star formation in the
cluster. The exact order of these star formation events is not yet
understood.
These results compare well with those found at higher resolution and
show the value of more extensive lower resolution spectral surveys.
They also highlight the need for large samples of stars when working
with a complex object like ω Cen.
Description:
The spectroscopic library, photometry, model atmospheres and line
lists used are the same as in Paper I (Simpson et al.,
2012MNRAS.427.1153S 2012MNRAS.427.1153S, Cat. J/MNRAS/427/1153)
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table3.dat 74 915 Stellar parameters determined for the 912 stars
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See also:
J/MNRAS/427/1153 : Stellar parameters of giants in ω Cen (Simpson+, 2012)
Byte-by-byte Description of file: table3.dat
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Bytes Format Units Label Explanations
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1- 5 I5 --- LEID [6/96011] LEID number (von Loon et al. 2007,
Cat. J/MNRAS/382/1353)
<Cl* NGC 5139 LEID NNNNN> in Simbad
7- 22 A16 ---- 2MASS 2MASS name (HHMMSSss+DDMMSSs)
24- 29 I6 --- B+09 [181/375016]? Identification number from
Bellini et al. 2009A&A...507.1393B 2009A&A...507.1393B
31- 34 I4 K Teff [3650/6650] Effective temperature
36- 38 F3.1 [cm/s2] logg [0.3/3.5] Surface gravity
40- 43 F4.1 [Sun] [Fe/H] [-3.5/0.6] Metallicity
45- 48 F4.1 [Sun] [C/Fe] [[-4.2/3.1] Abundance [C/Fe]
50- 53 F4.1 [Sun] [N/Fe] [-3.4/3.7] Abundance [N/Fe]
55- 58 F4.1 [Sun] [Ba/Fe] [-3/4] Abundance [Ba/Fe]
60- 63 F4.1 [Sun] [O/Fe] [-0.5/0.4] Abundance [O/Fe]
65 I1 --- Group [1/4]? Group number (1)
66- 74 A9 --- Note [NonMember ] Non member
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Note (1): Qualitative description and quantitative values of the four groups,
based upon table 6 of Paper I.
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Group [Fe/H] [C/Fe] [N/Fe] [Ba/Fe]
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1 Low Low Low Low
-1.8 -0.4 0.3 -0.4
2 Intermediate High Low Intermediate
-1.7 0.0 0.4 0.4
3 Intermediate Low High Intermediate
-1.7 -0.5 1.0 0.5
4 High Low High High
-1.3 -0.6 1.8 0.8
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History:
From electronic version of the journal
References:
Simpson et al., Paper I 2012MNRAS.427.1153S 2012MNRAS.427.1153S, Cat. J/MNRAS/427/1153
(End) Patricia Vannier [CDS] 18-Jul-2014