J/A+A/539/A19 Horizontal branch stars in NGC 1851 (Gratton+, 2012)
The Na-O anticorrelation in horizontal branch stars. II. NGC 1851.
Gratton R.G., Lucatello S., Carretta E., Bragaglia A., D'orazi V.,
Al Momany Y., Sollima A., Salaris M., Cassisi S.
<Astron. Astrophys., 539, A19 (2012)>
=2012A&A...539A..19G 2012A&A...539A..19G
ADC_Keywords: Clusters, globular ; Abundances ; Stars, horizontal branch
Keywords: stars: evolution - stars: abundances - stars: Population II -
globular clusters: general - globular clusters: individual: NGC 1851
Abstract:
The chemical composition of horizontal branch (HB) stars might help to
clarify the formation history of individual globular clusters (GCs).
We studied the Na-O anti-correlation from moderately high resolution
spectra for 91 stars on the bimodal HB of NGC 1851; in addition we
observed 13 stars on the lower red giant branch (RGB). In our HB
sample, 35 stars are on the blue HB (BHB), one is an RR Lyrae, and 55
stars are on the red HB (RHB). The ratio of BHB to RHB stars is close
to the total in the cluster (35 and 54%, respectively), while RR Lyrae
variables are under-represented, (they are ∼12% of the NGC 1851
stars). We also derived abundances for He and N in BHB stars.
Description:
We acquired spectra for 35 stars on the BHB, 1 RR Lyrae variable, 57
stars on the RHB, and 13 on the lower RGB (luminosity below the bump)
of NGC 1851 using the GIRAFFE fibre-fed spectrograph at VLT .
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table1.dat 69 103 Basic data for program stars
table2.dat 48 103 Atmospheric parameters and Fe abundances
table3.dat 71 97 Abundances of other elements (with corrected
values of [Al/Fe] from erratum in A&A, 547, C2)
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See also:
J/A+A/534/A123 : Horizontal branch stars in NGC 2808 (Gratton+, 2011)
J/A+A/549/A41 : Horizontal branch stars in 47 Tuc and M5 (Gratton+, 2013)
Byte-by-byte Description of file: table1.dat
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Bytes Format Units Label Explanations
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1- 4 A4 --- Type Type of variable (G1)
6- 10 I5 --- Star Star designation
12- 13 I2 h RAh Right ascension (J2000)
15- 16 I2 min RAm Right ascension (J2000)
18- 23 F6.3 s RAs Right ascension (J2000)
25 A1 --- DE- Declination sign (J2000)
26- 27 I2 deg DEd Declination (J2000)
29- 30 I2 arcmin DEm Declination (J2000)
32- 36 F5.2 arcsec DEs Declination (J2000)
38- 43 F6.3 mag Bmag ? B magnitude
45- 50 F6.3 mag Vmag ? V magnitude
52- 57 F6.3 mag Kmag ? K magnitude
59- 63 F5.1 km/s RV Radial velocity
65- 66 I2 --- S/N12 ? Signal-to-noise ratio of the Giraffe
spectrograph in HR12 grating (5808-6138Å)
68- 69 I2 --- S/N19 ? Signal-to-noise ratio of the Giraffe
spectrograph in HR19 grating (7728-8317Å)
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Byte-by-byte Description of file: table2.dat
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Bytes Format Units Label Explanations
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1- 4 A4 --- Type Type of variable (G1)
6- 10 I5 --- Star Star designation
12- 16 I5 K Teff Effective temperature
18- 21 F4.2 [cm/s2] logg Log surface gravity
23- 24 I2 --- o_[Fe/H]1 ? Number of FeI lines
26- 30 F5.2 [Sun] [Fe/H]1 ? Value of [Fe/H] from FeI lines
32- 35 F4.2 [Sun] e_[Fe/H]1 ? rms of [Fe/H] from FeI lines
37 I1 --- o_[Fe/H]2 ? Number of FeII lines
39- 43 F5.2 [Sun] [Fe/H]2 ? Value of [Fe/H] from FeII lines
45- 48 F4.2 [Sun] e_[Fe/H]2 ? rms of [Fe/H] from FeII lines
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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- 4 A4 --- Type Type of variable (G1)
6- 10 I5 --- Star Star designation
12 A1 --- l_[N/Fe] Limit flag on [N/Fe]
13- 16 F4.2 [Sun] [N/Fe] ? Value of [N/Fe] from CN lines
18- 22 F5.2 [Sun] [O/Fe] ? Value of [O/Fe] from OI lines
24 A1 --- l_[Na/Fe] Limit flag on [Na/Fe]
25- 29 F5.2 [Sun] [Na/Fe] ? Value of [Na/Fe] from NaI lines
31 A1 --- l_[Mg/Fe]1 Limit flag on [Mg/Fe]I
32- 36 F5.2 [Sun] [Mg/Fe]1 ? Value of [Mg/Fe] from MgI lines
38- 41 F4.2 [Sun] [Mg/Fe]2 ? Value of [Mg/Fe] from MgII lines
43- 47 F5.2 [Sun] [Al/Fe] ? Value of [Al/Fe] from AlI lines (1)
49- 53 F5.2 [Sun] [Si/Fe] ? Value of [Si/Fe] from SiI lines
55- 59 F5.2 [Sun] [Ca/Fe] ? Value of [Ca/Fe] from CaI lines
61- 65 F5.2 [Sun] [Mn/Fe] ? Value of [Mn/Fe] from MnI lines
67- 71 F5.2 [Sun] [Ba/Fe] ? Value of [Ba/Fe] from BaII lines
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Note (1): The Al abundances in NGC 1851 RHB stars given in Table 3 have been
corrected upward by 0.2dex (from original published table) because authors
realized they were obtained by assuming an inconsistent, too high,
solar abundance. Here, [Al/Fe] CONTAINS THE CORRECTED VALUES.
(from erratum in A&A, 547, C2)
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Global notes:
Note (G1): Variable types as follows:
BHB = Blue Horizontal-Branch (HB) star
RRL = RR Lyrae
RHB = Red Horizontal-Branch (HB) star
LRGB = Lower Red Giant Branch (RGB)
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History:
From electronic version of the journal
References:
Gratton et al., Paper I 2011A&A...534A.123G 2011A&A...534A.123G, Cat. J/A+A/534/123
Gratton et al., Paper III 2013A&A...549A..41G 2013A&A...549A..41G, Cat. J/A+A/549/A41
(End) Patricia Vannier [CDS] 17-Oct-2012