1998AJ....115.1640M

Query : 1998AJ....115.1640M

1998AJ....115.1640M - Astron. J., 115, 1640-1647 (1998/April-0)

Barium abundances in extremely metal-poor stars.

McWILLIAM A.

Abstract (from CDS):

New, improved, barium abundances for 33 extremely metal-poor halo stars from the 1995 sample of McWilliam et al. have been computed. The mean [Ba/Eu] ratio for stars with [Fe/H] ≤ -2.4 is -0.69±0.06 dex, consistent with pure r-process nucleosynthesis within the measurement uncertainties. Although the [Sr/Fe] and [Ba/Fe] abundance ratios span a range of 2.6 dex, the mean values are approximately constant with [Fe/H]. This is consistent with a model of chemical evolution in which the parent clouds were enriched by small numbers of supernova events. In this model, the decreasing heavy-element dispersion with increasing [Fe/H] is simply due to the averaging of element yields from many supernovae at higher [Fe/H]; however, it is necessary to increase the number of extremely metal-poor stars known in order to confirm this picture. In addition to the random Sr component from the r-process, the [Sr/Ba] ratios indicate that there is a second, also random, source of Sr from an as yet unidentified nucleosynthesis site.

Abstract Copyright: ∼

Journal keyword(s): Galaxy: Abundances - Galaxy: Evolution - Galaxy: Halo - Stars: Abundances - Stars: Population II

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 HD 2796 Pe* 00 31 16.9147531152 -16 47 40.790991624 9.58 9.28 8.50 8.14 8.67 Fw 193 0
2 HD 4306 SB* 00 45 27.1616035344 -09 32 39.785396712 9.80 9.75 9.02 8.75   G3/5w(A) 159 0
3 CD-38 245 Pe* 00 46 36.1954514592 -37 39 33.555030480   12.733 11.929 13.39 10.996 KIIvw 224 0
4 HD 5426 PM* 00 55 41.0497469496 -33 45 11.452751640   10.32 9.65 9.43 8.76 G(wp) 59 0
5 BPS CS 22953-0003 Pe* 01 02 15.8723379360 -61 43 45.836012208   14.43 13.75 13.339 12.886 KIIvw 70 0
6 HD 6268 Pe* 01 03 18.1716378504 -27 52 49.953768852   9.725 9.046 8.601   F/Gw 153 0
7 HD 13979 Pe* 02 15 20.8534060680 -25 54 54.872825148   9.81 9.18     F/Gw 88 0
8 HE 0239-1340 Pe* 02 41 42.3721546152 -13 28 10.603797240   14.73 13.97 13.566 13.080 CEMP-no 59 0
9 HE 0305-5442 Pe* 03 06 29.5014981984 -54 30 32.498486568   14.44 13.70 13.212 12.715 KIIvw 74 0
10 BPS CS 22877-0011 Pe* 13 14 40.1709557784 -09 35 46.570950420   14.49 13.81 13.96   ~ 23 0
11 HD 126587 Pe* 14 27 00.3636631296 -22 14 38.992940592   9.88 9.60 8.75   CEMP-no 132 0
12 HD 128279 Pe* 14 36 48.5108525999 -29 06 46.612858494 8.64 8.63 8.00     Gw 194 0
13 HD 140283 Pe* 15 43 03.0971190219 -10 56 00.595693188 7.508 7.711 7.212 6.63 8.21 F9VkA5mA1 937 0
14 BPS CS 22878-0101 Pe* 16 45 31.4513454168 +08 14 45.470265900   14.59 13.79   12.673 KIIvw 60 0
15 HD 178443 HB* 19 10 36.8478001512 -43 16 36.165827604 10.82 10.73 10.05     F8 51 0
16 BPS CS 22947-0187 HB* 19 18 31.6265761728 -47 13 31.155549384   13.63 12.99 12.508 12.085 CEMP-s 39 0
17 BPS CS 22891-0200 Pe* 19 35 19.0776472464 -61 42 24.374080224   14.77 13.93   12.79 CEMP-no 41 0
18 BPS CS 22891-0209 Pe* 19 42 02.1802427088 -61 03 44.534898612   13.03 12.18     KIIvw 57 0
19 UCAC2 7177623 Pe* 19 42 26.8926894816 -56 58 34.059037980   14.27 13.63     ~ 51 0
20 HD 186478 SB* 19 45 14.1409752672 -17 29 27.071239056   10.116 9.302 8.527 7.961 K2III 154 0
21 UCAC2 5726991 Pe* 19 53 49.7804195664 -59 40 00.163242192   13.592 12.620   11.48 KIIvw 47 0
22 BD-18 5550 Pe* 19 58 49.7371417608 -18 12 11.140126164 10.18 10.03 9.35 9.04 8.74 CEMP-no 173 0
23 HE 2002-5843 Pe* 20 07 03.7915948392 -58 34 57.592948836   13.72 13.03   12.102 CEMP-no 27 0
24 BPS CS 22873-0166 Pe* 20 19 22.0362485016 -61 30 15.119987544   12.818 11.802 11.52 10.57 KIIvw 55 0
25 BPS CS 22885-0096 Pe* 20 20 51.1730095656 -39 53 30.234972840   14.02 13.33     CEMP-no 88 0
26 BPS CS 22950-0046 Pe* 20 21 28.3975657104 -13 16 33.601931364   15.13 14.224 13.639 13.066 CEMP-no 40 0
27 BPS CS 22897-0008 Pe* 21 03 11.8565397504 -65 05 08.852220600   14.02 13.33     CEMP-no 70 0
28 HD 200654 Pe* 21 06 34.7513254468 -49 57 50.280288000   9.74 9.1     CEMP 107 0
29 HE 2141-3741 RG* 21 44 51.1647807408 -37 27 55.017356112   14.10 13.47     CEMP-no 55 0
30 BPS CS 22892-0052 Pe* 22 17 01.6558764360 -16 39 27.051026544   14.03 13.20 13.06 12.19 KIIvw 448 0
31 BPS CS 22949-0048 Pe* 23 26 07.4169241824 -05 50 06.903492036   14.48 13.67 13.154 12.639 CEMP-no 33 0
32 HE 2323-0256 Pe* 23 26 29.8073738880 -02 39 58.036383180   15.12 14.36   13.358 CEMP-no 180 0
33 HE 2334-0604 RG* 23 37 28.6873103640 -05 47 56.594641632   14.03 13.28 12.768 12.249 KIIvw 70 0
34 BPS CS 22998-0027 * ~ ~   13.090 12.58     ~ 2 0

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