2016A&A...587A.124K


C.D.S. - SIMBAD4 rel 1.7 - 2020.07.15CEST07:58:53

2016A&A...587A.124K - Astronomy and Astrophysics, volume 587A, 124-124 (2016/3-1)

Metal-poor stars towards the Galactic bulge: A population potpourri.

KOCH A., McWILLIAM A., PRESTON G.W. and THOMPSON I.B.

Abstract (from CDS):

We present a comprehensive chemical abundance analysis of five red giants and two horizontal branch (HB) stars towards the southern edge of the Galactic bulge, at (l, b)~(0°,-11°). Based on high-resolution spectroscopy obtained with the Magellan/MIKE spectrograph, we derived up to 23 chemical element abundances and identify a mixed bag of stars, representing various populations in the central regions of the Galaxy. Although cosmological simulations predict that the inner Galaxy was host to the first stars in the Universe, we see no chemical evidence of the ensuing massive supernova explosions: all of our targets exhibit halo-like, solar [Sc/Fe] ratios, which is in contrast to the low values predicted from Population III nucleosynthesis. One of the targets is a CEMP-s star at [Fe/H]=-2.52dex, and another target is a moderately metal-poor ([Fe/H]=-1.53dex) CH star with strong enrichment in s-process elements (e.g., [Ba/Fe]=1.35). These individuals provide the first contenders of these classes of stars towards the bulge. Four of the carbon-normal stars exhibit abundance patterns reminiscent of halo star across a metallicity range spanning -2.0 to -2.6dex, i.e., enhanced α-elements and solar Fe-peak and neutron-capture elements, and the remaining one is a regular metal-rich bulge giant. The position, distance, and radial velocity of one of the metal-poor HB stars coincides with simulations of the old trailing arm of the disrupted Sagittarius dwarf galaxy. While their highly uncertain proper motions prohibit a clear kinematic separation, the stars' chemical abundances and distances suggest that these metal-poor candidates, albeit located towards the bulge, are not of the bulge, but rather inner halo stars on orbits that make them pass through the central regions. Thus, we caution similar claims of detections of metal-poor stars as true habitants of the bulge.

Abstract Copyright:

Journal keyword(s): stars: abundances - stars: carbon - stars: Population II - Galaxy: abundances - Galaxy: bulge - Galaxy: halo

VizieR on-line data: <Available at CDS (J/A+A/587/A124): table1.dat table2.dat table3.dat>

Nomenclature: Table 1: [KMP2016] NNNNN N=7 among (Nos 10464-37860) = [KMP2016] JHHMMSS.ss+DDMMSS.s.

Simbad objects: 15

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Number of rows : 15

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 NAME Sgr Stream St* 02 22 +00.0           ~ 645 0
2 HD 84937 PM* 09 48 56.09801 +13 44 39.3237 8.49 8.68 8.32 7.97 7.70 F8Vm-5 717 0
3 HD 122563 Pe* 14 02 31.8456299772 +09 41 09.942736952 7.47 7.10 6.19 5.37 4.79 G8:III:Fe-5 746 0
4 NGC 5897 GlC 15 17 24.40 -21 00 36.4   10.16 8.52     ~ 337 0
5 NAME Gal Center reg 17 45 40.04 -29 00 28.1           ~ 11542 0
6 [KMP2016] 10464 HB* 18 30 03.8645552286 -33 34 23.663806918   16.02 15.27     ~ 2 0
7 [KMP2016] 37860 HB* 18 30 25.7307088851 -34 31 30.028639794   16.023 15.29     ~ 1 0
8 2MASS J18311326-3351481 RG* 18 31 13.2631043796 -33 51 48.179118714   16.58 15.55     ~ 2 0
9 2MASS J18325649-3445289 RG* 18 32 56.4945581306 -34 45 28.999633055   15.726 14.92     ~ 1 0
10 2MASS J18333852-3429408 RG* 18 33 38.5315595834 -34 29 40.913375162   16.88 15.64     ~ 1 0
11 2MASS J18342676-3455556 RG* 18 34 26.7599645044 -34 55 55.663404413   15.876 15.03     ~ 1 0
12 2MASS J18355877-3458393 RG* 18 35 58.7748217430 -34 58 39.334463111   15.48 14.58     ~ 1 0
13 NAME SDG G 18 55 03.1 -30 28 42   4.5 3.6     ~ 1738 2
14 CD-62 1346 Pe* 21 06 02.9221670307 -61 33 44.645933103   10.55 9.85 9.56 9.027 CEMP-s 48 0
15 NAME Galactic Bulge reg ~ ~           ~ 3391 0

    Equat.    Gal    SGal    Ecl

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2020.07.15-07:58:53

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