2013AJ....145...25K

Query : 2013AJ....145...25K

2013AJ....145...25K - Astron. J., 145, 25 (2013/January-0)

The horizontal branch of NGC 1851: constraints from its RR Lyrae variables.

KUNDER A., SALARIS M., CASSISI S., DE PROPRIS R., WALKER A., STETSON P.B., CATELAN M. and AMIGO P.

Abstract (from CDS):

We use the pulsational properties of the RR Lyrae variables in the globular cluster NGC 1851 to obtain detailed constraints of the various sub-stellar populations present along its horizontal branch. On the basis of detailed synthetic horizontal branch modeling, we find that minor helium variations (Y ∼ 0.248-0.280) are able to reproduce the observed periods and amplitudes of the RR Lyrae variables, as well as the frequency of fundamental and first-overtone RR Lyrae stars. Comparison of number ratios among the blue and red horizontal branch components and the two observed subgiant branches also suggest that the RR Lyrae variables originated from the progeny of the bright subgiant branch. The RR Lyrae variables with slightly enhanced helium (Y ∼ 0.270-0.280) have longer periods at a given amplitude, as is seen with Oosterhoff II (OoII) RR Lyrae variables, whereas the RR Lyrae variables with Y ∼ 0.248-0.270 have shorter periods, exhibiting properties of Oosterhoff I (OoI) variables. This correlation does suggest that the pulsational properties of RR Lyrae stars can be very useful for tracing the various subpopulations and can provide suitable constraints on the multiple population phenomenon. It appears to be of great interest to explore whether this conclusion can be generalized to other globular clusters hosting multiple populations.

Abstract Copyright: ∼

Journal keyword(s): Galaxy: stellar content - globular clusters: general - globular clusters: individual: NGC 1851 - stars: horizontal-branch - stars: Population II - stars: variables: RR Lyrae

Simbad objects: 41

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Number of rows : 41
N Identifier Otype ICRS (J2000)
RA 		ICRS (J2000)
DEC 		Mag U Mag B Mag V Mag R Mag I Sp type #ref
1850 - 2026 		#notes
1 NGC 362 GlC 01 03 14.26 -70 50 55.6     6.58     ~ 1167 0
2 NGC 1851 GlC 05 14 06.76 -40 02 47.6           ~ 1529 0
3 M 79 GlC 05 24 10.59 -24 31 27.3     8.16     ~ 883 0
4 NAME CMa Dwarf Galaxy G 07 12.6 -27 40     -0.1     ~ 203 1
5 NGC 2419 GlC 07 38 08.51 +38 52 54.9     10.05     ~ 998 0
6 NGC 2808 GlC 09 12 03.10 -64 51 48.6           ~ 1540 0
7 NGC 3201 GlC 10 17 36.82 -46 24 44.9           ~ 1001 0
8 NGC 4147 GlC 12 10 06.149 +18 32 31.78   11.45 10.74     ~ 616 0
9 Cl Ruprecht 106 GlC 12 38 40.20 -51 09 01.0           ~ 413 0
10 M 68 GlC 12 39 27.98 -26 44 38.6     7.96     ~ 1069 0
11 M 53 GlC 13 12 55.25 +18 10 05.4     7.79     ~ 907 0
12 NGC 5053 GlC 13 16 27.09 +17 42 00.9     9.96     ~ 675 0
13 NGC 5139 GlC 13 26 47.28 -47 28 46.1           ~ 3677 0
14 M 3 GlC 13 42 11.62 +28 22 38.2     6.39     ~ 2593 0
15 NGC 5286 GlC 13 46 26.81 -51 22 27.3           ~ 485 0
16 NGC 5466 GlC 14 05 27.29 +28 32 04.0     9.70     ~ 887 0
17 IC 4499 GlC 15 00 18.57 -82 12 49.6     8.56     ~ 375 0
18 M 5 GlC 15 18 33.22 +02 04 51.7     5.95     ~ 2095 0
19 NGC 5986 GlC 15 46 03.00 -37 47 11.1     6.92     ~ 408 0
20 M 4 GlC 16 23 35.22 -26 31 32.7           ~ 1978 0
21 NGC 6101 GlC 16 25 48.12 -72 12 07.9           ~ 337 0
22 M 107 GlC 16 32 31.86 -13 03 13.6           ~ 835 0
23 NGC 6229 GlC 16 46 58.641 +47 31 36.38   9.38 9.86     ~ 397 0
24 M 62 GlC 17 01 12.60 -30 06 44.5           ~ 668 0
25 M 92 GlC 17 17 07.39 +43 08 09.4     6.52     ~ 2240 0
26 M 9 GlC 17 19 11.78 -18 30 58.5   9.36 8.42     ~ 348 0
27 NGC 6362 GlC 17 31 54.99 -67 02 54.0           ~ 637 0
28 NGC 6388 GlC 17 36 17.461 -44 44 08.34           ~ 988 1
29 NGC 6426 GlC 17 44 54.71 +03 10 12.5           ~ 244 0
30 NGC 6441 GlC 17 50 13.06 -37 03 05.2           ~ 940 0
31 M 28 GlC 18 24 32.89 -24 52 11.4           ~ 821 0
32 NGC 6712 GlC 18 53 04.32 -08 42 21.5           ~ 550 0
33 M 54 GlC 18 55 03.33 -30 28 47.5           ~ 1164 0
34 NGC 6723 GlC 18 59 33.15 -36 37 56.1           ~ 543 0
35 M 55 GlC 19 39 59.71 -30 57 53.1     6.49     ~ 913 0
36 M 75 GlC 20 06 04.841 -21 55 20.14     8.26     ~ 394 0
37 NGC 6934 GlC 20 34 11.37 +07 24 16.1           ~ 459 0
38 M 72 GlC 20 53 27.70 -12 32 14.3     8.96     ~ 465 0
39 NGC 7006 GlC 21 01 29.465 +16 11 16.49     10.46     ~ 562 0
40 M 15 GlC 21 29 58.33 +12 10 01.2           ~ 3274 0
41 M 2 GlC 21 33 27.02 -00 49 23.7     6.25     ~ 1114 1

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