J/A+A/603/A37 4 globular clusters RGB and AGB stars (Gruyters+, 2017)
First evidence of multiple populations along the AGB from Stromgren photometry.
Gruyters P., Casagrande L., Milone A.P., Hodgkin S.T., Serenelli A.,
Feltzing S.
<Astron. Astrophys. 603, A37 (2017)>
=2017A&A...603A..37G 2017A&A...603A..37G (SIMBAD/NED BibCode)
ADC_Keywords: Positional data ; Clusters, globular ; Models, atmosphere ;
Photometry, uvby
Keywords: Hertzsprung-Russell and C-Mdiagrams - stars: abundance -
techniques: photometry - globular clusters: general
Abstract:
Spectroscopic studies have demonstrated that nearly all Galactic
globular clusters (GCs) harbour multiple stellar populations with
different chemical compositions. Moreover, colour-magnitude diagrams
based exclusively on Stroemgrem photometry have allowed us to identify
and characterise multiple populations along the RGB of a large number
of clusters. In this paper we show for the first time that Stroemgren
photometry is also very efficient at identifying multiple populations
along the AGB, and demonstrate that the AGB of M3, M92, NGC362,
NGC1851, and NGC6752 are not consistent with a single stellar
population. We also provide a catalogue of RGB and AGB stars
photometrically identified in these clusters for further spectroscopic
follow-up studies. We combined photometry and elemental abundances
from the literature for RGB and AGB stars in NGC6752 where the
presence of multiple populations along the AGB has been widely
debated. We find that, while the MS, SGB, and RGB host three stellar
populations with different helium and light element abundances, only
two populations of AGB stars are present in the cluster. These results
are consistent with standard evolutionary theory.
Description:
Coordinates and Stromgren photometry is given for RGB and AGB stars in
four Globular clusters. Photometry for NGC362, NGC1851 and NGC6341 is
taken from the Grundahl catalogue (see Calamida et al.
2007ApJ...670..400C 2007ApJ...670..400C). Ra and dec were derived for these stars by
crossmatching to 2MASS. Coordinates and Stromgren uvby photometry for
117 RGB and 22 AGB stars in M3 were derived as part of the SAGA survey
(see Casagrande et al., 2014, Cat. J/ApJ/787/110). PSF photometric
measurements were derived using the method and the computer programs
by Anderson & King (2006acs..rept....1A) and Anderson et al.
(2006A&A...454.1029A 2006A&A...454.1029A) adapted to the INT/WFC camera. This data is part
of the SAGA survey (see Casagrande et al., 2014, Cat. J/ApJ/787/110).
File Summary:
--------------------------------------------------------------------------------
FileName Lrecl Records Explanations
--------------------------------------------------------------------------------
ReadMe 80 . This file
tableb1.dat 49 320 Positions and y-mag of RGB and AGB stars in the
Grundahl data of NGC362, NGC1851 and NGC6341
tableb2.dat 62 139 Position and uvby photometry of RGB and AGB
stars in the globular cluster M3
--------------------------------------------------------------------------------
See also:
J/ApJ/787/110 : SAGA: Stromgren survey of seismic KIC stars (Casagrande+, 2014)
Byte-by-byte Description of file: tableb1.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 7 A7 --- Cluster Globular Cluster ID
9- 14 I6 --- Star Star ID, within the cluster
16- 26 F11.7 deg RAdeg Right ascension (J2000)
28- 38 F11.7 deg DEdeg Declination (J2000)
40- 45 F6.3 mag ymag Stromgren y magnitude
47- 49 A3 --- Phase Evolutionary phase (AGB or RGB)
-------------------------------------------------------------------------------
Byte-by-byte Description of file: tableb2.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 10 A10 --- ID Star ID
12- 22 F11.7 deg RAdeg Right ascension (J2000)
24- 34 F11.7 deg DEdeg Declination (J2000)
36- 41 F6.3 mag umag Stromgren u magnitude
43- 48 F6.3 mag vmag Stromgren v magnitude
50- 55 F6.3 mag bmag Stromgren b magnitude
57- 62 F6.3 mag ymag Stromgren y magnitude
-------------------------------------------------------------------------------
Acknowledgements:
Pieter Gruyters, pieter.gruyters(at)gmail.com
(End) Pieter Gruyters [LU, Sweden], Patricia Vannier [CDS] 27-Apr-2017