2011A&A...527L...9K


C.D.S. - SIMBAD4 rel 1.7 - 2019.09.22CEST02:26:26

2011A&A...527L...9K - Astronomy and Astrophysics, volume 527, L9-9 (2011/3-1)

Strong radial segregation between sub-populations of evolutionary homogeneous stars in the Galactic globular cluster NGC 6752.

KRAVTSOV V., ALCAINO G., MARCONI G. and ALVARADO F.

Abstract (from CDS):

We investigate the new and still poorly studied matter of so-called multiple stellar populations (MSPs) in Galactic globular clusters (GGCs). Studying MSPs and their accumulated data can shed more light on the formation and evolution of GGCs and other closely related fundamental problems. We focus on the strong relation between the radial distribution of evolutionary homogeneous stars and their U-based photometric characteristics in the nearby GGC NGC6752 and compare this with a similar relation we found in NGC 3201 and NGC1261. We use our new multi-color photometry in a fairly wide field of NGC6752, with particular emphasis on the U band and our recent and already published photometry made in NGC 3201 and NGC1261. We found and report here for the first time a strong difference in the radial distribution between the sub-populations of red giant branch (RGB) stars that are bluer and redder in color (U-B), as well as between sub-giant branch (SGB) stars brighter and fainter in the U-magnitude in NGC6752. Moreover, the fainter SGB and redder RGB stars are similarly much more centrally concentrated than their respective brighter and bluer counterparts. Virtually the same applies to NGC3201. We find evidence in NGC6752 as in NGC3201 that a dramatic change in the proportion of the two sub-populations of SGB and RGB stars occurs at a radial distance close to the half-mass radius, Rh, of the cluster. These results are the first detections of the radial trend of the particular photometric properties of stellar populations in GGCs. They imply a radial dependence of the main characteristics of the stellar populations in these GGCs, primarily of the abundance, and (indirectly) presumably of the kinematics.

Abstract Copyright:

Journal keyword(s): globular clusters: general - globular clusters: individual: NGC 6752 - globular clusters: individual: NGC 3201 - globular clusters: individual: NGC 1261

Simbad objects: 9

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Number of rows : 9

N Identifier Otype ICRS (J2000)
RA
ICRS (J2000)
DEC
Mag U Mag B Mag V Mag R Mag I Sp type #ref
1850 - 2019
#notes
1 NGC 1261 GlC 03 12 16.21 -55 12 58.4   9.79 8.63     ~ 400 0
2 NGC 1851 GlC 05 14 06.76 -40 02 47.6   8.80 7.23     ~ 1202 0
3 NGC 1978 GlC 05 28 45.330 -66 14 12.04   10.7 10.70     ~ 258 0
4 IRAS 09110-6439 GlC 09 12 03.10 -64 51 48.6   7.77 5.69     ~ 1192 0
5 NGC 3201 GlC 10 17 36.82 -46 24 44.9   9.18 8.24     ~ 678 0
6 MGC 6752 * 10 25 18.2689734287 +00 13 18.426308341   15.39       ~ 2 0
7 NGC 5139 GlC 13 26 47.28 -47 28 46.1   6.12 5.33     ~ 2897 0
8 M 4 GlC 16 23 35.22 -26 31 32.7           ~ 1627 0
9 NGC 6752 GlC 19 10 52.11 -59 59 04.4   6.96 6.28     ~ 1757 0

    Equat.    Gal    SGal    Ecl

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2019.09.22-02:26:26

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