2007A&A...467..107D


C.D.S. - SIMBAD4 rel 1.7 - 2019.09.18CEST00:01:02

2007A&A...467..107D - Astronomy and Astrophysics, volume 467, 107-115 (2007/5-3)

NGC 2298: a globular cluster on its way to disruption.

DE MARCHI G. and PULONE L.

Abstract (from CDS):

We have studied the stellar main sequence (MS) of the globular cluster NGC2298 using deep HST/ACS observations in the F606W and F814W bands covering an area of 3.4'x3.4' around the cluster centre or about twice the cluster's half-mass radius. The colour-magnitude diagram that we derive in this way reveals a narrow and well defined MS extending down to the 10σ detection limit at m606≃26.5, m814≃25, corresponding to stars of ∼0.2M. The luminosity function (LF) obtained with these data, once corrected for the limited effects of photometric incompleteness, reveals a remarkable deficiency of low-mass stars as well as a radial gradient, in that the LF becomes progressively steeper with radius. Using the mass-luminosity relation appropriate for the metallicity of NGC2298, we derive the cluster's global mass function (GMF) by using a multi-mass Michie-King model. Over the range 0.8-0.2M, the number of stars per unit mass decreases following a power-law distribution of the type dN/dm∝m0.5, where, for comparison, typical halo clusters have dN/dm∝m–1.5. If the IMF of NGC2298 was similar to that of other metal poor halo clusters, like e.g. NGC6397, the present GMF that we obtain implies that this object must have lost of the order of 85% of its original mass, at a rate much higher than that suggested by current models based on the available cluster orbit. The latter may, therefore, need revision.

Abstract Copyright:

Journal keyword(s): stars: Hertzsprung-Russell (HR) and C-M diagrams - stars: luminosity function, mass function - Galaxy: globular clusters: general - Galaxy: globular clusters: individual: NGC 2298

Simbad objects: 7

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Number of rows : 7

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 2298 GlC 06 48 59.41 -36 00 19.1   10.77 8.89     ~ 404 0
2 NAME Serpens Dwarf GlC 15 16 05.30 -00 06 41.0   15.1       ~ 593 1
3 M 12 GlC 16 47 14.18 -01 56 54.7   8.52 6.07     ~ 554 0
4 NGC 6397 GlC 17 40 42.09 -53 40 27.6   7.39 5.17     ~ 1747 1
5 NAME Gal Center reg 17 45 40.04 -29 00 28.1           ~ 10920 0
6 NGC 6712 GlC 18 53 04.32 -08 42 21.5   9.85 8.69     ~ 456 0
7 M 71 GlC 19 53 46.49 +18 46 45.1   7.91 6.1     ~ 990 0

    Equat.    Gal    SGal    Ecl

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2019.09.18-00:01:02

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