2006A&A...456.1085M


C.D.S. - SIMBAD4 rel 1.7 - 2020.11.29CET00:28:15

2006A&A...456.1085M - Astronomy and Astrophysics, volume 456, 1085-1096 (2006/9-4)

Global fitting of globular cluster age indicators.

MEISSNER F. and WEISS A.

Abstract (from CDS):

Stellar models and the methods for the age determinations of globular clusters are still in need of improvement. We attempt to obtain a more objective method of age determination based on cluster diagrams, avoiding the introduction of biases due to the preference of one single age indicator. We compute new stellar evolutionary tracks and derive the dependence of age indicating points along the tracks and isochrone - such as the turn-off or bump location - as a function of age and metallicity. The same critical points are identified in the colour-magnitude diagrams of globular clusters from a homogeneous database. Several age indicators are then fitted simultaneously, and the overall best-fitting isochrone is selected to determine the cluster age. We also determine the goodness-of-fit for different sets of indicators to estimate the confidence level of our results. We find that our isochrones provide no acceptable fit for all age indicators. In particular, the location of the bump and the brightness of the tip of the red giant branch are problematic. On the other hand, the turn-off region is very well reproduced, and restricting the method to indicators depending on it results in trustworthy ages. Using an alternative set of isochrones improves the situation, but neither leads to an acceptable global fit. We conclude that evolutionary tracks of low-mass metal-poor stars are far from reproducing all aspects of globular cluster colour-magnitude diagrams and that the determination of cluster ages still depends on the favourite method or indicator chosen.

Abstract Copyright:

Journal keyword(s): stars: evolution - Galaxy: globular clusters: general

Simbad objects: 46

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Number of rows : 46

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     ~ 3584 0
2 NGC 362 GlC 01 03 14.26 -70 50 55.6     6.58     ~ 948 0
3 NGC 1261 GlC 03 12 16.21 -55 12 58.4     8.63     ~ 434 0
4 NGC 1851 GlC 05 14 06.76 -40 02 47.6   8.80 7.23     ~ 1253 0
5 M 79 GlC 05 24 10.59 -24 31 27.3   9.21 8.16     ~ 723 0
6 NGC 2808 GlC 09 12 03.10 -64 51 48.6   7.77 5.69     ~ 1258 0
7 NGC 3201 GlC 10 17 36.82 -46 24 44.9   9.18 8.24     ~ 736 0
8 NGC 4147 GlC 12 10 06.149 +18 32 31.78   11.45 10.74     ~ 500 0
9 M 68 GlC 12 39 27.98 -26 44 38.6   10.26 7.96     ~ 888 0
10 NGC 4833 GlC 12 59 33.92 -70 52 35.4   8.72 7.79     ~ 355 0
11 M 53 GlC 13 12 55.25 +18 10 05.4   8.95 7.79     ~ 723 0
12 NGC 5634 GlC 14 29 37.28 -05 58 35.1   10.69 10.05     ~ 251 0
13 NGC 5694 GlC 14 39 36.52 -26 32 18.0   11.58 10.89     ~ 269 0
14 NGC 5824 GlC 15 03 58.612 -33 04 06.70   10.28 9.56     ~ 345 0
15 M 5 GlC 15 18 33.22 +02 04 51.7   7.34 5.95     ~ 1787 0
16 NGC 5927 GlC 15 28 00.69 -50 40 22.9   10.13 8.86     ~ 407 0
17 NGC 5986 GlC 15 46 03.00 -37 47 11.1     6.92     ~ 309 0
18 M 80 GlC 16 17 02.41 -22 58 33.9           ~ 624 0
19 M 107 GlC 16 32 31.86 -13 03 13.6   9.96 8.85     ~ 710 0
20 M 13 GlC 16 41 41.634 +36 27 40.75     5.8     ~ 2020 0
21 M 62 GlC 17 01 12.60 -30 06 44.5   8.55 7.39     ~ 521 0
22 M 19 GlC 17 02 37.69 -26 16 04.6   8.45 5.57     ~ 311 1
23 NGC 6284 GlC 17 04 28.747 -24 45 51.22   10.72 7.43     ~ 240 0
24 NGC 6287 GlC 17 05 09.4907827015 -22 42 28.100632364   11.49 10.30     ~ 198 0
25 NGC 6293 GlC 17 10 10.42 -26 34 54.2   9.96 9.02     ~ 243 0
26 NGC 6304 GlC 17 14 32.25 -29 27 43.3   10.33 9.03     ~ 302 0
27 NGC 6356 GlC 17 23 34.99 -17 48 46.9   10.01 7.42     ~ 321 1
28 NGC 6362 GlC 17 31 54.99 -67 02 54.0   9.72 8.86     ~ 494 0
29 NGC 6522 GlC 18 03 34.08 -30 02 02.3   10.68 9.48     ~ 458 1
30 NGC 6544 GlC 18 07 20.58 -24 59 50.4   11.36 9.90     ~ 238 0
31 NGC 6584 GlC 18 18 37.60 -52 12 56.8   10.32 8.17     ~ 248 0
32 NGC 6624 GlC 18 23 40.51 -30 21 39.7           ~ 782 1
33 NGC 6638 GlC 18 30 56.25 -25 29 47.1   10.81 9.68     ~ 194 0
34 M 69 GlC 18 31 23.10 -32 20 53.1   9.32 8.31     ~ 407 1
35 NGC 6642 GlC 18 31 54.23 -23 28 34.1   11.30 10.24     ~ 162 0
36 NGC 6652 GlC 18 35 45.63 -32 59 26.6   10.64 9.75     ~ 353 0
37 M 70 GlC 18 43 12.76 -32 17 31.6   9.76 9.06     ~ 335 0
38 NGC 6712 GlC 18 53 04.32 -08 42 21.5   9.85 8.69     ~ 472 0
39 NGC 6723 GlC 18 59 33.15 -36 37 56.1           ~ 433 0
40 M 71 GlC 19 53 46.49 +18 46 45.1   7.91 6.1     ~ 1028 0
41 M 75 GlC 20 06 04.841 -21 55 20.14     8.26     ~ 317 0
42 NGC 6934 GlC 20 34 11.37 +07 24 16.1   10.48 9.75     ~ 363 0
43 M 72 GlC 20 53 27.70 -12 32 14.3   9.95 8.96     ~ 369 0
44 M 15 GlC 21 29 58.33 +12 10 01.2   3       ~ 2925 0
45 M 2 GlC 21 33 27.02 -00 49 23.7     6.25     ~ 908 1
46 M 30 GlC 21 40 22.12 -23 10 47.5     7.10     ~ 927 0

    Equat.    Gal    SGal    Ecl

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2020.11.29-00:28:15

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