2010A&A...517A..81G


C.D.S. - SIMBAD4 rel 1.7 - 2020.07.09CEST07:39:24

2010A&A...517A..81G - Astronomy and Astrophysics, volume 517, A81-81 (2010/7-1)

The second and third parameters of the horizontal branch in globular clusters.

GRATTON R.G., CARRETTA E., BRAGAGLIA A., LUCATELLO S. and D'ORAZI V.

Abstract (from CDS):

The second parameter (the first being metallicity) defining the distribution of stars on the horizontal branch (HB) of globular clusters (GCs) has long been one of the major open issues in our understanding of the evolution of normal stars. Large photometric and spectroscopic databases are now available: they include large and homogeneous sets of colour-magnitude diagrams, cluster ages, and homogeneous data about chemical compositions from our FLAMES survey. We use these databases to re-examine this issue. We use the photometric data to derive median and extreme (i.e., the values including 90% of the distribution) colours and magnitudes of stars along the HB for about a hundred GCs. We transform these into median and extreme masses of stars on the HB, using the models developed by the Pisa group, and taking into account evolutionary effects. We compare these masses with those expected at the tip of the red giant branch (RGB) to derive the total mass lost by the stars. We find that a simple linear dependence on metallicity of this total mass lost describes quite well the median colours of HB stars. Assuming this mass loss law to be universal, we find that age is the main second parameter, determining many of the most relevant features related to HBs. In particular, it allows us to explain the Oosterhoff dichotomy as a consequence of the peculiar age-metallicity distribution of GCs in our Galaxy, although both Oosterhoff groups have GCs spanning a rather wide range of ages. However, at least an additional - third - parameter is clearly required. The most likely candidate is the He abundance, which might be different in GC stars belonging to the different stellar generations whose presence was previously derived from the Na-O and Mg-Al anticorrelations. Variations in the median He abundance allow us to explain the extremely blue HB of GCs like NGC 6254 (=M 10) and NGC 1904 (=M 79); such variations are found to be (weakly) correlated with the values of the R-parameter (that is the ratio of the number of stars on the HB and on the RGB). We also show that suitable He abundances allow deriving ages from the HB which are consistent with those obtained from the Main Sequence. Small corrections to these latter ages are then proposed. We find that a very tight age-metallicity relation (with a scatter below 4%) can be obtained for GCs kinematically related to the disk and bulge, once these corrections are applied. Furthermore, star-to-star variations in the He content, combined with a small random term, explain very well the extension of the HB. There is a strong correlation between this extension and the interquartile of the Na-O anticorrelation, strongly supporting the hypothesis that the third parameter for GC HBs is He. Finally, there are strong indications that the main driver for these variations in the He-content within GCs is the total cluster mass. There are a few GCs exhibiting exceptional behaviours (including NGC 104=47 Tuc and in less measure NGC 5272=M 3); however, they can be perhaps accommodated in a scenario for the formation of GCs that relates their origin to cooling flows generated after very large episodes of star formation, as proposed by Carretta et al. (2009d, accepted).

Abstract Copyright:

Journal keyword(s): globular clusters: general - stars: abundances

VizieR on-line data: <Available at CDS (J/A+A/517/A81): table1.dat table2.dat table3.dat table4.dat table5.dat table6.dat table7.dat table8.dat table10.dat table11.dat table12.dat>

Simbad objects: 102

goto Full paper

goto View the reference in ADS

Number of rows : 102

N Identifier Otype ICRS (J2000)
RA
ICRS (J2000)
DEC
Mag U Mag B Mag V Mag R Mag I Sp type #ref
1850 - 2020
#notes
1 NGC 104 GlC 00 24 05.359 -72 04 53.20   5.78 4.09     ~ 3547 0
2 NGC 288 GlC 00 52 45.24 -26 34 57.4   10 8.13     ~ 918 0
3 NGC 362 GlC 01 03 14.26 -70 50 55.6     6.58     ~ 938 0
4 NAME Magellanic Clouds GrG 03 00 -71.0           ~ 5665 1
5 NGC 1261 GlC 03 12 16.21 -55 12 58.4   9.79 8.63     ~ 426 0
6 NGC 1851 GlC 05 14 06.76 -40 02 47.6   8.80 7.23     ~ 1241 0
7 NAME LMC G 05 23 34.6 -69 45 22     0.4     ~ 14826 1
8 M 79 GlC 05 24 10.59 -24 31 27.3   9.21 8.16     ~ 716 0
9 NGC 2298 GlC 06 48 59.41 -36 00 19.1   10.77 8.89     ~ 423 0
10 NGC 2419 GlC 07 38 08.51 +38 52 54.9     10.05     ~ 815 0
11 IRAS 09110-6439 GlC 09 12 03.10 -64 51 48.6   7.77 5.69     ~ 1244 0
12 NAME E 3 GlC 09 20 57.07 -77 16 54.8           ~ 128 0
13 NGC 3201 GlC 10 17 36.82 -46 24 44.9   9.18 8.24     ~ 722 0
14 NGC 4147 GlC 12 10 06.149 +18 32 31.78   11.45 10.74     ~ 495 0
15 NGC 4372 GlC 12 25 45.43 -72 39 32.7   10.86 9.85     ~ 263 0
16 NGC 4499 GiG 12 32 04.944 -39 58 56.83   13.58   12.20   ~ 32 0
17 M 68 GlC 12 39 27.98 -26 44 38.6   10.26 7.96     ~ 876 0
18 NGC 4833 GlC 12 59 33.92 -70 52 35.4   8.72 7.79     ~ 350 0
19 M 53 GlC 13 12 55.25 +18 10 05.4   8.95 7.79     ~ 713 0
20 NGC 5053 GlC 13 16 27.09 +17 42 00.9     9.96     ~ 533 0
21 NGC 5139 GlC 13 26 47.28 -47 28 46.1   6.12 5.33     ~ 2996 0
22 M 3 GlC 13 42 11.62 +28 22 38.2     6.39     ~ 2265 0
23 NGC 5466 GlC 14 05 27.29 +28 32 04.0   10.5 9.70     ~ 719 0
24 NGC 5634 GlC 14 29 37.28 -05 58 35.1   10.69 10.05     ~ 246 0
25 NGC 5694 GlC 14 39 36.52 -26 32 18.0   11.58 10.89     ~ 268 0
26 IC 4499 GlC 15 00 18.57 -82 12 49.6     8.56     ~ 310 0
27 NGC 5824 GlC 15 03 58.612 -33 04 06.70   10.28 9.56     ~ 341 0
28 NGC 5897 GlC 15 17 24.40 -21 00 36.4   10.16 8.52     ~ 337 0
29 M 5 GlC 15 18 33.22 +02 04 51.7   7.34 5.95     ~ 1771 0
30 NGC 5927 GlC 15 28 00.69 -50 40 22.9   10.13 8.86     ~ 404 0
31 NGC 5946 GlC 15 35 28.58 -50 39 35.0   11.98 10.72     ~ 165 0
32 NGC 5986 GlC 15 46 03.00 -37 47 11.1     6.92     ~ 306 0
33 M 80 GlC 16 17 02.41 -22 58 33.9           ~ 617 0
34 M 4 GlC 16 23 35.22 -26 31 32.7           ~ 1676 0
35 NGC 6101 GlC 16 25 48.12 -72 12 07.9   10.90 10.08     ~ 237 0
36 NGC 6139 GlC 16 27 39.987 -38 50 57.03   11.03 9.68     ~ 179 0
37 M 107 GlC 16 32 31.86 -13 03 13.6   9.96 8.85     ~ 702 0
38 M 13 GlC 16 41 41.634 +36 27 40.75     5.8     ~ 2006 0
39 NGC 6229 GlC 16 46 58.641 +47 31 36.38   9.38 9.86     ~ 314 0
40 M 12 GlC 16 47 14.18 -01 56 54.7   8.52 6.07     ~ 579 0
41 NGC 6235 GlC 16 53 25.36 -22 10 38.8   11.99 7.20     ~ 160 0
42 M 10 GlC 16 57 09.05 -04 06 01.1     4.98     ~ 683 0
43 NGC 6256 GlC 16 59 32.68 -37 07 17.1           ~ 115 0
44 M 62 GlC 17 01 12.60 -30 06 44.5   8.55 7.39     ~ 512 0
45 M 19 GlC 17 02 37.69 -26 16 04.6   8.45 5.57     ~ 307 1
46 NGC 6284 GlC 17 04 28.747 -24 45 51.22   10.72 7.43     ~ 237 0
47 NGC 6287 GlC 17 05 09.4907827015 -22 42 28.100632364   11.49 10.30     ~ 196 0
48 NGC 6293 GlC 17 10 10.42 -26 34 54.2   9.96 9.02     ~ 243 0
49 NGC 6304 GlC 17 14 32.25 -29 27 43.3   10.33 9.03     ~ 298 0
50 NGC 6316 GlC 17 16 37.42 -28 08 24.0   10.33 9.03     ~ 178 0
51 M 92 GlC 17 17 07.39 +43 08 09.4     6.52     ~ 1904 0
52 NGC 6325 GlC 17 17 59.27 -23 45 57.7   11.49       ~ 140 0
53 NGC 6342 GlC 17 21 10.14 -19 35 14.7   11.25 10.01     ~ 246 0
54 NGC 6356 GlC 17 23 34.99 -17 48 46.9   10.01 7.42     ~ 320 1
55 NGC 6355 GlC 17 23 58.65 -26 21 12.3   12.46 11.05     ~ 126 0
56 NGC 6352 GlC 17 25 29.11 -48 25 19.8   9.95 8.87     ~ 340 0
57 IC 1257 Bz? 17 27 06.00 -07 05 00.0           ~ 60 0
58 NGC 6366 GlC 17 27 44.24 -05 04 47.5           ~ 261 0
59 NGC 6362 GlC 17 31 54.99 -67 02 54.0   9.72 8.86     ~ 487 0
60 NGC 6380 GlC 17 34 28.00 -39 04 09.0           ~ 97 0
61 NGC 6388 GlC 17 36 17.461 -44 44 08.34   7.40       ~ 805 1
62 M 14 GlC 17 37 36.15 -03 14 45.3   9.55 5.73     ~ 316 0
63 NGC 6401 GlC 17 38 36.93 -23 54 31.5   11.31 10.71     ~ 130 0
64 NGC 6397 GlC 17 40 42.09 -53 40 27.6   7.39 5.17     ~ 1798 1
65 NGC 6440 GlC 17 48 52.67 -20 21 34.5   12.01 10.10     ~ 469 1
66 NGC 6441 GlC 17 50 13.06 -37 03 05.2   9.26 8.00     ~ 768 0
67 NGC 6453 GlC 17 50 51.77 -34 35 55.1   10.49       ~ 130 0
68 NGC 6496 GlC 17 59 03.68 -44 15 57.4   9.96       ~ 181 0
69 NGC 6517 GlC 18 01 50.376 -08 57 34.39   11.08       ~ 145 0
70 NGC 6522 GlC 18 03 34.08 -30 02 02.3   10.68 9.48     ~ 455 1
71 NGC 6535 GlC 18 03 50.51 -00 17 51.5   11.35 9.85     ~ 241 0
72 NGC 6539 GlC 18 04 49.74 -07 35 09.1           ~ 194 0
73 NGC 6540 GlC 18 06 08.60 -27 45 55.0           ~ 90 0
74 NGC 6544 GlC 18 07 20.58 -24 59 50.4   11.36 9.90     ~ 233 0
75 NGC 6541 GlC 18 08 02.36 -43 42 53.6   8.06 7.32     ~ 321 1
76 NGC 6569 GlC 18 13 38.88 -31 49 35.2   10.78 9.47     ~ 188 0
77 NGC 6584 GlC 18 18 37.60 -52 12 56.8   10.32 8.17     ~ 244 0
78 NGC 6624 GlC 18 23 40.51 -30 21 39.7           ~ 774 1
79 M 28 GlC 18 24 32.89 -24 52 11.4           ~ 662 0
80 NGC 6638 GlC 18 30 56.25 -25 29 47.1   10.81 9.68     ~ 193 0
81 M 69 GlC 18 31 23.10 -32 20 53.1   9.32 8.31     ~ 405 1
82 NGC 6642 GlC 18 31 54.23 -23 28 34.1   11.30 10.24     ~ 162 0
83 NGC 6652 GlC 18 35 45.63 -32 59 26.6   10.64 9.75     ~ 349 0
84 M 22 GlC 18 36 23.94 -23 54 17.1   7.16 6.17     ~ 1217 0
85 RSGC 1 OpC 18 37 58 -06 53.0           ~ 87 0
86 Cl Stephenson 2 OpC 18 39 20 -06 01.7           ~ 82 0
87 M 70 GlC 18 43 12.76 -32 17 31.6   9.76 9.06     ~ 331 0
88 NGC 6712 GlC 18 53 04.32 -08 42 21.5   9.85 8.69     ~ 468 0
89 M 54 GlC 18 55 03.33 -30 28 47.5           ~ 898 0
90 NGC 6717 GlC 18 55 06.04 -22 42 05.3   11.29 10.35     ~ 194 0
91 NGC 6723 GlC 18 59 33.15 -36 37 56.1           ~ 430 0
92 NGC 6752 GlC 19 10 52.11 -59 59 04.4   6.96 6.28     ~ 1806 0
93 NGC 6760 GlC 19 11 12.06 +01 01 49.7   11.37 9.78     ~ 205 0
94 M 56 GlC 19 16 35.57 +30 11 00.5   8.90       ~ 359 0
95 M 55 GlC 19 39 59.71 -30 57 53.1     6.49     ~ 758 0
96 M 71 GlC 19 53 46.49 +18 46 45.1   7.91 6.1     ~ 1024 0
97 M 75 GlC 20 06 04.841 -21 55 20.14     8.26     ~ 314 0
98 NGC 6934 GlC 20 34 11.37 +07 24 16.1   10.48 9.75     ~ 359 0
99 M 72 GlC 20 53 27.70 -12 32 14.3   9.95 8.96     ~ 365 0
100 M 15 GlC 21 29 58.33 +12 10 01.2   3       ~ 2907 0
101 M 2 GlC 21 33 27.02 -00 49 23.7     6.25     ~ 899 1
102 M 30 GlC 21 40 22.12 -23 10 47.5     7.10     ~ 913 0

    Equat.    Gal    SGal    Ecl

To bookmark this query, right click on this link: simbad:objects in 2010A&A...517A..81G and select 'bookmark this link' or equivalent in the popup menu


2020.07.09-07:39:24

© Université de Strasbourg/CNRS

    • Contact