J/A+A/541/A15 Abundances of M22 subgiants (Marino+, 2012)
The double sub-giant branch of NGC 6656 (M22): a chemical characterization. Marino A.F., Milone A.P., Sneden C., Bergemann M., Kraft R.P., Wallerstein G., Cassisi S., Aparicio A., Asplund M., Bedin R.L., Hilker M., Lind K., Momany Y., Piotto G., Roederer I.U., Stetson P.B., Zoccali M. <Astron. Astrophys., 541, A15 (2012)> =2012A&A...541A..15M
ADC_Keywords: Clusters, globular ; Stars, giant ; Abundances Keywords: techniques: spectroscopic - stars: abundances - stars: Population II - globular clusters: individual: NGC 6656 Abstract: We present an abundance analysis of 101 subgiant branch (SGB) stars in the globular cluster M22. Using low-resolution FLAMES/GIRAFFE spectra we have determined abundances of the neutron-capture strontium and barium and the light element carbon. With these data we explore relationships between the observed SGB photometric split in this cluster and two stellar groups characterized by different contents of iron, slow neutron-capture process (s-process) elements, and the α element calcium, which we previously discovered in M22's red-giant stars. Description: Ground-based observations were used to analyze the CMD over a wide spatial field in the B and V bands and to estimate the atmospheric parameters of the spectroscopic targets. In addition, we used ground-based U images available for a smaller field, and images taken with the Advanced Camera for Surveys onboard the HST (ACS/HST) in the F606W and F814W bands to make our study of the double SGB extend from the ultraviolet to the infrared spectral regions. The HST ACS/WFC images were obtained under program GO-10775 (PI Sarajedini). File Summary:
FileName Lrecl Records Explanations
ReadMe 80 . This file table2.dat 63 101 M22 targets: positions and photometric data table3.dat 44 101 M22 C, Sr, Ba abundances for SGB stars, listing standard deviation σSr for the two Sr lines and the s-group for each star
See also: J/ApJ/420/612 : Proper motions + radial velocities in M22 (Peterson+ 1994) J/PASP/107/32 : uvby-hk photometry in M22 (Anthony-Twarog+ 1995) J/ApJS/99/637 : Equivalent widths for 54 red giants (Norris+ 1995) J/A+A/373/899 : New variables in M22 globular cluster (Kaluzny+, 2001) J/MNRAS/349/1278 : BVI photometry of M22 (Monaco+, 2004) Byte-by-byte Description of file: table2.dat
Bytes Format Units Label Explanations
1- 4 I4 --- ID Identification number (1) 6- 7 I2 h RAh Right ascension (J2000) 9- 10 I2 min RAm Right ascension (J2000) 12- 16 F5.2 s RAs Right ascension (J2000) 18 A1 --- DE- Declination sign (J2000) 19- 20 I2 deg DEd Declination (J2000) 22- 23 I2 arcmin DEm Declination (J2000) 25- 28 F4.1 arcsec DEs Declination (J2000) 30- 35 F6.3 mag Umag ?=99.999 U magnitude (2) 37- 42 F6.3 mag Bmag B magnitude (3) 44- 49 F6.3 mag Vmag V magnitude (3) 51- 56 F6.3 mag Imag I magnitude (3) 58- 63 F6.3 mag dE(B-V) Differential reddening correction values for each target star, δE(B-V)
Note (1): From the ground-based photometric catalog described in Sect. 2.1. Note (2): Momany et al. (2004A&A...420..605M) photometric database. Note (3): Stetson photometric database.
Byte-by-byte Description of file: table3.dat
Bytes Format Units Label Explanations
1- 4 I4 --- ID Identification number 6- 9 I4 K Teff Effective temperature 11- 14 F4.2 [cm/s2] logg Surface gravity 16- 20 F5.2 [-] [Sr/Fe] Abundance [Sr/Fe] 22- 25 F4.2 [-] eSr ?=- Standard deviation σSr for the two Sr lines 27- 31 F5.2 [-] [Ba/Fe] ?=- Abundance [Ba/Fe] 33- 37 F5.2 [-] [C/Fe] ?=- Abundance [C/Fe] 39- 44 A6 --- s-group s-group (s-poor or s-rich) (1)
Note (1): Global metallicities of [A/H]=-1.82 and [A/H]=-1.67 were employed for s-poor and s-rich stars, respectively (see Sect. 3.1 for more details).
History: From electronic version of the journal
(End) Patricia Vannier [CDS] 25-Jun-2012
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