2019ApJ...883...84R

Query : 2019ApJ...883...84R

2019ApJ...883...84R - Astrophys. J., 883, 84-84 (2019/September-3)

High-resolution optical spectroscopy of stars in the Sylgr stellar stream.

ROEDERER I.U. and GNEDIN O.Y.

Abstract (from CDS):

We observe two metal-poor main-sequence stars that are members of the recently discovered Sylgr stellar stream. We present radial velocities, stellar parameters, and abundances for 13 elements derived from high-resolution optical spectra collected using the Magellan Inamori Kyocera Echelle spectrograph. The two stars have identical compositions (within 0.13 dex or 1.2σ) among all elements detected. Both stars are very metal-poor ([Fe/H] = -2.92 ± 0.06). Neither star is highly enhanced in C ([C/Fe] < +1.0). Both stars are enhanced in the α elements Mg, Si, and Ca ([α/Fe] = +0.32 ± 0.06), and the ratios among Na, Al, and all Fe-group elements are typical for other stars in the halo and ultra-faint and dwarf spheroidal galaxies at this metallicity. Sr is mildly enhanced ([Sr/Fe] = +0.22 ± 0.11), but Ba is not enhanced ([Ba/Fe] < -0.4), indicating that these stars do not contain high levels of neutron-capture elements. The Li abundances match those found in metal-poor unevolved field stars and globular clusters (GCs) (log ε(Li) = 2.05 ± 0.07), which implies that environment is not a dominant factor in determining the Li content of metal-poor stars. The chemical compositions of these two stars cannot distinguish whether the progenitor of the Sylgr stream was a dwarf galaxy or a GC. If the progenitor was a dwarf galaxy, the stream may originate from a dense region such as a nuclear star cluster. If the progenitor was a GC, it would be the most metal-poor GC known.

Abstract Copyright: © 2019. The American Astronomical Society. All rights reserved.

Journal keyword(s): dwarf galaxies 416 - globular star clusters 656 - nucleosynthesis 1131 - Population II stars - Stellar abundances

VizieR on-line data: <Available at CDS (J/ApJ/883/84): table1.dat table2.dat>

Simbad objects: 49

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Number of rows : 49
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 NAME Tri II G 02 13 17.40 +36 10 42.4           ~ 164 0
2 NAME Segue 2 G 02 19 16.0 +20 10 31     15.2     ~ 299 0
3 NAME Hor I G 02 55 31.7 -54 07 08           ~ 169 0
4 NAME Reticulum II G 03 35 42.1 -54 02 57           ~ 375 0
5 NGC 2419 GlC 07 38 08.51 +38 52 54.9     10.05     ~ 998 0
6 NAME UMa II Galaxy G 08 51 30.0 +63 07 48     13.3     ~ 410 0
7 HD 84937 Pe* 09 48 56.0992891997 +13 44 39.326709913 8.49 8.68 8.32 7.97 7.70 F8Vm-5 831 0
8 NAME Segue 1 G 10 07 03.2 +16 04 25     15.3     ~ 517 1
9 NAME Sextans dSph LSB 10 13 02.9 -01 36 53   12 10.4     ~ 921 0
10 Z 126-111 G 11 13 28.13 +22 09 10.1   12.9 12.0     ~ 899 0
11 NAME Leo IV LSB 11 32 57.0 -00 32 00     15.1     ~ 419 1
12 2MASS J12022092-0020387 Pe* 12 02 20.9151669240 -00 20 38.815915884           A0 4 0
13 SDSS J120825.36+002440.4 Pe* 12 08 25.3666717632 +00 24 40.489583112           A0 4 0
14 NGC 4372 GlC 12 25 45.43 -72 39 32.7   10.86 9.85     ~ 327 0
15 NAME Coma Dwarf Galaxy G 12 26 59.0 +23 54 15     14.1     ~ 482 1
16 M 68 GlC 12 39 27.98 -26 44 38.6     7.96     ~ 1069 0
17 NAME CVn II dSph G 12 57 09.6 +34 19 12     16.1     ~ 287 2
18 NGC 4833 GlC 12 59 33.92 -70 52 35.4           ~ 467 0
19 M 53 GlC 13 12 55.25 +18 10 05.4     7.79     ~ 907 0
20 NGC 5053 GlC 13 16 27.09 +17 42 00.9     9.96     ~ 675 0
21 NGC 5139 GlC 13 26 47.28 -47 28 46.1           ~ 3677 0
22 NAME CVn I dSph G 13 28 03.5 +33 33 21     13.1     ~ 352 1
23 Wolf 1492 Pe* 13 40 02.4921849768 -00 02 18.750053436 11.601 11.832 11.451 11.184 10.892 sdF0: 299 0
24 NAME Bootes II G 13 58 00.0 +12 51 00     15.4     ~ 269 0
25 NAME Bootes Dwarf Spheroidal Galaxy G 14 00 00.0 +14 30 00     12.8     ~ 491 0
26 HD 126587 Pe* 14 27 00.3636631296 -22 14 38.992940592   9.88 9.60 8.75   CEMP-no 145 0
27 NGC 5694 GlC 14 39 36.52 -26 32 18.0           ~ 323 0
28 NGC 5824 GlC 15 03 58.612 -33 04 06.70   10.28 9.56     ~ 441 0
29 Z 318-18 G 15 09 08.0 +67 13 21   13.60 10.6     ~ 1459 0
30 NGC 5897 GlC 15 17 24.40 -21 00 36.4   10.16 8.52     ~ 424 0
31 NAME Hercules Dwarf Galaxy G 16 31 02.0 +12 47 30     14.0     ~ 379 1
32 M 12 GlC 16 47 14.18 -01 56 54.7     6.07     ~ 736 0
33 M 10 GlC 16 57 09.05 -04 06 01.1     4.98     ~ 857 0
34 NGC 6287 GlC 17 05 09.4906767360 -22 42 28.099250172   11.49 10.30     ~ 240 0
35 M 92 GlC 17 17 07.39 +43 08 09.4     6.52     ~ 2240 0
36 Z 300-12 G 17 20 14.335 +57 55 16.39   12.40 10.6     ~ 1428 1
37 NGC 6397 GlC 17 40 42.09 -53 40 27.6     5.17     ~ 2103 0
38 NGC 6426 GlC 17 44 54.71 +03 10 12.5           ~ 244 0
39 NAME Galactic Center reg 17 45 39.60213 -29 00 22.0000           ~ 16269 0
40 NGC 6535 GlC 18 03 50.51 -00 17 51.5     9.85     ~ 320 0
41 M 55 GlC 19 39 59.71 -30 57 53.1     6.49     ~ 913 0
42 Cl Terzan 8 GlC 19 41 44.41 -33 59 58.1     11.54     ~ 357 0
43 M 15 GlC 21 29 58.33 +12 10 01.2           ~ 3274 0
44 M 30 GlC 21 40 22.12 -23 10 47.5     7.10     ~ 1121 0
45 NAME Tuc II G 22 51 55.1 -58 34 08           ~ 192 0
46 NAME Grus I G 22 56 42.4 -50 09 48           ~ 126 0
47 NAME Sylgr Stream St* 23 02 -14.           ~ 24 0
48 NAME Tuc III G 23 56.6 -59 36           ~ 229 0
49 NAME Local Group GrG ~ ~           ~ 9325 0

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