2019A&A...627A..70K


Query : 2019A&A...627A..70K

2019A&A...627A..70K - Astronomy and Astrophysics, volume 627A, 70-70 (2019/7-1)

Chemical composition of the outer halo globular cluster Palomar 15.

KOCH A., XU S. and RICH R.M.

Abstract (from CDS):

Globular clusters (GCs) in the outer Milky Way halo are important tracers of the assembly history of our Galaxy. Only a few of these objects show spreads in heavier elements beyond the canonical light-element variations that have essentially been found throughout the entire Galactic GC system, suggesting a more complex origin and evolution of these objects. Here, we present the first abundance analysis of three red giants in the remote (RGC=38kpc) outer halo GC Palomar 15, based on medium-resolution spectra obtained with the Keck/ESI instrument. Our results ascertain a low iron abundance of -1.94±0.06dex with no evidence of any significant abundance spreads, although this is based on low number statistics. Overall, abundance ratios of 16 species were measured, including carbon, Na, Al, α-peak (Mg,Si,Ca,Ti) and Fe-peak (Sc,V,Cr,Fe,Co,Ni) elements, and the three neutron-capture elements Sr, Ba, and Eu. The majority of abundances are compatible with those of halo field stars and those found in other GCs in the outer and inner halos at similar metallicity. Pal 15 is enhanced to [Mg/Fe]=0.45dex, while other α-elements, Ca and Ti, are lower by 0.3dex. Taking Mg as a representative for [α/Fe], and coupled with the lack of any significant spread in any of the studied elements we conclude that Pal 15 is typical of the outer halo, as is bolstered by its chemical similarity to the benchmark outer halo cluster NGC 7492. One star shows evidence of elevated Na and Al abundances, hinting at the presence of multiple stellar populations in this cluster.

Abstract Copyright: © ESO 2019

Journal keyword(s): Galaxy: abundances - Galaxy: evolution - globular clusters: individual: Palomar 15 - globular clusters: general - Galaxy: halo

CDS comments: Table 1 objects 3584, 8469 and 11726 are respectively 2MASS J16595214-0033231, 2MASS J16595190-0032538 and 2MASS J16595605-0032232.

Simbad objects: 34

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Number of rows : 34
N Identifier Otype ICRS (J2000)
RA
ICRS (J2000)
DEC
Mag U Mag B Mag V Mag R Mag I Sp type #ref
1850 - 2024
#notes
1 M 31 AGN 00 42 44.330 +41 16 07.50 4.86 4.36 3.44     ~ 12725 1
2 NAME Cetus-Palca Stream St* 01 31 +01.0           ~ 71 1
3 NAME Whiting 1 GlC 02 02 56.8 -03 15 10           ~ 153 0
4 NAME Eridanus ClG GrG 03 38 32.00 -22 18 51.0           ~ 179 0
5 NAME E 1 GlC 03 55 02.5 -49 36 52           ~ 212 0
6 Cl Pal 2 GlC 04 46 05.91 +31 22 53.4   15       ~ 186 0
7 NGC 1851 GlC 05 14 06.76 -40 02 47.6           ~ 1441 0
8 NGC 2419 GlC 07 38 08.51 +38 52 54.9     10.05     ~ 940 0
9 Koposov 2 GlC 07 58 17.00 +26 15 19.4           ~ 71 1
10 NAME PYX GLOBULAR CL GlC 09 07 57.80 -37 13 17.0           ~ 110 0
11 NAME Sextans C GlC 10 05 30.96 +00 04 15.4   15.5 13.9     ~ 333 1
12 GCl 17 GlC 11 29 16.80 +28 58 25.0   14.4       ~ 359 1
13 Koposov 1 GlC 11 59 18.40 +12 15 35.8           ~ 71 0
14 NGC 4147 GlC 12 10 06.149 +18 32 31.78   11.45 10.74     ~ 579 0
15 M 3 GlC 13 42 11.62 +28 22 38.2     6.39     ~ 2488 0
16 C 1353-269 GlC 13 56 21.702 -27 10 03.00           ~ 134 0
17 NGC 5634 GlC 14 29 37.28 -05 58 35.1   10.69 10.05     ~ 305 0
18 NGC 5694 GlC 14 39 36.52 -26 32 18.0           ~ 305 0
19 NGC 5824 GlC 15 03 58.612 -33 04 06.70   10.28 9.56     ~ 412 0
20 NAME Serpens Dwarf GlC 15 16 05.30 -00 06 41.0   15.1       ~ 744 1
21 GCl 38 GlC 16 10 59.00 +14 57 42.0           ~ 373 0
22 M 13 GlC 16 41 41.634 +36 27 40.75     5.8     ~ 2202 0
23 NGC 6229 GlC 16 46 58.641 +47 31 36.38   9.38 9.86     ~ 372 0
24 GCl 50 GlC 16 59 51.1 -00 32 00   15.70       ~ 204 1
25 2MASS J16595190-0032538 NIR 16 59 51.9171572640 -00 32 53.832751188     16.770   15.381 ~ 1 0
26 2MASS J16595214-0033231 NIR 16 59 52.1615481360 -00 33 23.169212136     16.601   15.204 ~ 1 0
27 2MASS J16595605-0032232 NIR 16 59 56.0602296720 -00 32 23.270703576     16.902   15.573 ~ 1 0
28 NGC 6397 GlC 17 40 42.09 -53 40 27.6     5.17     ~ 1986 0
29 NGC 6426 GlC 17 44 54.71 +03 10 12.5           ~ 226 0
30 Cl Arp 2 GlC 19 28 44.11 -30 21 20.3     12.41     ~ 359 0
31 M 75 GlC 20 06 04.841 -21 55 20.14     8.26     ~ 371 0
32 NGC 7006 GlC 21 01 29.465 +16 11 16.49     10.46     ~ 537 0
33 GCl 124 GlC 23 06 44.48 +12 46 19.2   15.6       ~ 281 1
34 NGC 7492 GlC 23 08 26.68 -15 36 41.3     10.48     ~ 305 0

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