2009A&A...507.1393B


C.D.S. - SIMBAD4 rel 1.7 - 2021.02.27CET06:17:05

2009A&A...507.1393B - Astronomy and Astrophysics, volume 507, 1393-1408 (2009/12-1)

Radial distribution of the multiple stellar populations in ω Centauri.

BELLINI A., PIOTTO G., BEDIN L.R., KING I.R., ANDERSON J., MILONE A.P. and MOMANY Y.

Abstract (from CDS):

We present a detailed study of the radial distribution of the multiple populations identified in the Galactic globular cluster ω Cen. We used both space-based images (ACS/WFC and WFPC2) and ground-based images (FORS1LT and WFI.2m ESO telescopes) to map the cluster from the inner core to the outskirts (∼20arcmin). These data sets have been used to extract high-accuracy photometry for the construction of color-magnitude diagrams and astrometric positions of ∼900000 stars. We find that in the inner ∼2 core radii the blue main sequence (bMS) stars slightly dominate the red main sequence (rMS) in number. At greater distances from the cluster center, the relative numbers of bMS stars with respect to rMS drop steeply, out to ∼8arcmin, and then remain constant out to the limit of our observations. We also find that the dispersion of the Gaussian that best fits the color distribution within the bMS is significantly greater than the dispersion of the Gaussian that best fits the color distribution within the rMS. In addition, the relative number of intermediate-metallicity red-giant-branch stars (which includes the progeny of the bMS) with respect to the metal-poor component (the progeny of the rMS) follows a trend similar to that of the main-sequence star-count ratio NbMS/NrMS. The most metal-rich component of the red-giant branch follows the same distribution as the intermediate-metallicity component. We briefly discuss the possible implications of the observed radial distribution of the different stellar components in ω Cen.

Abstract Copyright:

Journal keyword(s): globular clusters: general - globular clusters: individual: ω Cen [NGC 5139] - stars: evolution - stars: population II - techniques: photometric

Simbad objects: 8

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Number of rows : 8

N Identifier Otype ICRS (J2000)
RA
ICRS (J2000)
DEC
Mag U Mag B Mag V Mag R Mag I Sp type #ref
1850 - 2021
#notes
1 NGC 104 GlC 00 24 05.359 -72 04 53.20   5.78 4.09     ~ 3616 0
2 NGC 1851 GlC 05 14 06.76 -40 02 47.6   8.80 7.23     ~ 1268 0
3 NGC 2808 GlC 09 12 03.10 -64 51 48.6   7.77 5.69     ~ 1277 0
4 NGC 5139 GlC 13 26 47.28 -47 28 46.1   6.12 5.33     ~ 3072 0
5 M 4 GlC 16 23 35.22 -26 31 32.7           ~ 1702 0
6 NGC 6388 GlC 17 36 17.461 -44 44 08.34   7.40       ~ 827 1
7 M 22 GlC 18 36 23.94 -23 54 17.1   7.16 6.17     ~ 1242 0
8 M 54 GlC 18 55 03.33 -30 28 47.5           ~ 932 0

    Equat.    Gal    SGal    Ecl

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2021.02.27-06:17:05

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