2004A&A...428.1027C


Query : 2004A&A...428.1027C

2004A&A...428.1027C - Astronomy and Astrophysics, volume 428, 1027-1037 (2004/12-4)

The Hamburg/ESO R-process Enhanced Star survey (HERES). I. Project description, and discovery of two stars with strong enhancements of neutron-capture elements.

CHRISTLIEB N., BEERS T.C., BARKLEM P.S., BESSELL M., HILL V., HOLMBERG J., KORN A.J., MARSTELLER B., MASHONKINA L., QIAN Y.-Z., ROSSI S., WASSERBURG G.J., ZICKGRAF F.-J., KRATZ K.-L., NORDSTROEM B., PFEIFFER B., RHEE J. and RYAN S.G.

Abstract (from CDS):

We report on a dedicated effort to identify and study metal-poor stars strongly enhanced in r-process elements ([r/Fe]>1dex; hereafter r-II stars), the Hamburg/ESO R-process Enhanced Star survey (HERES). Moderate-resolution (∼2Å) follow-up spectroscopy has been obtained for metal-poor giant candidates selected from the Hamburg/ESO objective-prism survey (HES) as well as the HK survey to identify sharp-lined stars with [Fe/H]←2.5dex. For several hundred confirmed metal-poor giants brighter than B∼16.5mag (most of them from the HES), ``snapshot'' spectra (R∼20000; S/N∼30 per pixel) are being obtained with VLT/UVES, with the main aim of finding the 2-3% r-II stars expected to be among them. These are studied in detail by means of higher resolution and higher S/N spectra. In this paper we describe a pilot study based on a set of 35 stars, including 23 from the HK survey, eight from the HES, and four comparison stars. We discovered two new r-II stars, CS 29497-004 ([Eu/Fe]=1.64±0.22) and CS 29491-069 ([Eu/Fe]=1.08±0.23). A first abundance analysis of CS 29497-004 yields that its abundances of Ba to Dy are on average enhanced by 1.5dex with respect to iron and the Sun and match a scaled solar r-process pattern well, while Th is underabundant relative to that pattern by 0.3dex, which we attribute to radioactive decay. That is, CS 29497-004 seems not to belong to the class of r-process enhanced stars displaying an ``actinide boost'', like CS 31082-001 (Hill et al., 2002A&A...387..560H), or CS 30306-132 (Honda et al., 2004ApJ...607..474H). The abundance pattern agrees well with predictions of the phenomenological model of Qian & Wasserburg (2002ApJ...567..515Q).

Abstract Copyright:

Journal keyword(s): surveys - stars: abundances - stars: population II - Galaxy: abundances - Galaxy: halo

Simbad objects: 42

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Number of rows : 42
N Identifier Otype ICRS (J2000)
RA
ICRS (J2000)
DEC
Mag U Mag B Mag V Mag R Mag I Sp type #ref
1850 - 2022
#notes
1 HD 20 Pe* 00 05 15.3242691048 -27 16 18.140091852   9.65 9.40 8.865 8.377 F2V 65 0
2 BPS CS 31060-0047 Pe* 00 08 07.8079252752 -15 54 03.796952616   14.62 13.80 13.296 12.784 ~ 8 0
3 BPS CS 30339-0041 Pe* 00 23 12.9329467992 -37 01 26.746269672 14.400 14.42 13.87   13.175 ~ 11 0
4 BPS CS 29497-0004 Pe* 00 28 06.9155612016 -26 03 04.269055032   14.76 14.07 13.583 13.116 ~ 48 0
5 BPS CS 31062-0041 Pe* 00 35 03.0121219128 -15 54 29.358443880   14.754 13.934 13.476 12.984 ~ 12 0
6 SKB 2 Pe* 00 41 39.8197621944 -26 18 54.460585116   13.338 12.221 11.704 11.321 CEMP-s 88 0
7 BPS CS 22183-0031 Pe* 01 09 05.0900915136 -04 43 21.343580436   14.24 13.62 13.178 12.724 ~ 41 0
8 HE 0109-3711 Pe* 01 11 38.4089770056 -36 55 17.114003076   16.668 16.290   15.691 ~ 7 0
9 BPS CS 31082-0001 Pe* 01 29 31.1311443552 -16 00 45.495314460 12.527 12.427 11.642 11.189 10.713 CEMP 266 0
10 HE 0131-2740 Pe* 01 33 25.7848514136 -27 25 28.017813360   15.222 14.632   13.836 ~ 9 0
11 BPS CS 22958-0083 Pe* 02 15 42.7299428184 -53 59 56.257460160 15.057 15.09 14.44 13.981 13.521 CEMP-no 21 0
12 BPS CS 22175-0007 Pe* 02 17 26.6223977472 -09 00 45.171469044   14.14 13.49 13.038 12.571 ~ 11 0
13 BPS CS 29510-0058 Pe* 02 21 46.5781548912 -24 01 58.700555292   14.2 13.53 13.070 12.628 ~ 10 0
14 HE 0249-0126 * 02 51 39.7277627112 -01 14 34.872820224   16.256 15.685 15.352 14.999 ~ 4 0
15 HE 0256-1109 Pe* 02 59 10.1814351456 -10 58 01.879190976   16.157 15.608 15.239 14.891 ~ 8 0
16 BPS CS 22186-0023 Pe* 04 19 45.5332495464 -36 51 35.980987284   13.57 12.84   11.925 ~ 15 0
17 BPS CS 22186-0025 Pe* 04 24 32.7982834272 -37 09 02.518136460   14.99 14.24 13.740 13.269 ~ 35 0
18 HE 0447-4858 Pe* 04 49 01.0006331976 -48 53 36.148568604   16.687 16.254   15.624 ~ 7 0
19 HE 0501-5139 Pe* 05 02 48.2100929328 -51 35 36.308316876   16.573 16.094 15.778 15.475 ~ 8 0
20 BPS CS 31072-0118 Pe* 05 08 53.5581065328 -59 18 21.741857136   13.63 12.71 12.135 11.573 ~ 12 0
21 HE 0513-4557 Pe* 05 15 12.2122904520 -45 54 10.460610036   16.279 15.743 15.428 15.045 ~ 7 0
22 HE 0519-5525 Pe* 05 19 59.1518278872 -55 22 41.811658860   15.570 15.034   14.284 ~ 7 0
23 HD 115444 Pe* 13 16 42.4590842616 +36 22 52.692135420   9.77 8.97 8.3 7.88 G9V 232 0
24 BPS CS 30306-0132 Pe* 15 14 18.9191634456 +07 27 02.680959780   13.62 12.73 12.421 11.948 ~ 31 0
25 BD+17 3248 HB* 17 28 14.4690179544 +17 30 35.847574776   10.02 9.34     KIIvw 207 0
26 BPS CS 30308-0035 Pe* 20 45 54.1494676176 -44 50 29.309879040   14.66 13.95 13.343 12.807 ~ 11 0
27 HE 2134-3940 Pe* 21 37 45.7673945880 -39 27 22.313379600   13.790 12.660 12.160 11.760 KIIvw 84 0
28 BPS CS 30343-0063 Pe* 21 45 17.5016952312 -37 22 18.529442436   14.04 12.99 12.375 11.774 ~ 8 0
29 HE 2145-3025 Pe* 21 48 43.3366071696 -30 11 08.365244532   15.402 14.879   14.155 ~ 7 0
30 HE 2148-1247 Pe* 21 51 17.9096426016 -12 33 41.557315896   15.2 14.79     CEMP-r/s 46 0
31 BPS CS 30337-0097 Pe* 22 01 21.5117972016 -30 57 57.614539932   13.98 13.22 12.693 12.161 ~ 11 0
32 BPS CS 22960-0010 Pe* 22 08 25.3504579344 -44 53 56.708357892   14.78 13.81 13.485 13.137 ~ 16 0
33 BPS CS 22892-0052 Pe* 22 17 01.6558764360 -16 39 27.051026544   14.03 13.20 13.06 12.19 KIIvw 427 0
34 BPS CS 22886-0042 Pe* 22 20 25.8163819488 -10 23 20.107482000   14.106 13.275 12.763 12.269 ~ 22 0
35 BPS CS 29491-0109 Pe* 22 25 01.1983330224 -32 14 41.336449404   14.02 13.21 12.686 12.129 ~ 9 0
36 BPS CS 29491-0069 Pe* 22 31 02.1859040712 -32 38 36.526573572   13.72 13.09 12.654 12.175 ~ 28 0
37 HD 221170 Pe* 23 29 28.8087143040 +30 25 57.849303180 9.43 8.74 7.66     G2IV 273 0
38 BPS CS 22945-0028 Pe* 23 31 13.5632038296 -66 29 57.771375900 15.167 15.32 14.64   13.728 ~ 16 0
39 BPS CS 30315-0029 Pe* 23 34 26.6960486448 -26 42 14.003379828   14.56 13.64 13.092 12.518 ~ 18 0
40 BPS CS 30315-0001 Pe* 23 37 38.8276106688 -26 21 53.215363836   14.65 13.76 13.188 12.640 ~ 6 0
41 HE 2338-1311 Pe* 23 41 08.3631890688 -12 55 09.709365972   16.219 15.622   14.907 ~ 7 0
42 BPS CS 22957-0013 Pe* 23 55 49.0555858200 -05 22 52.872713652   14.81 14.08 13.601 13.110 CEMP-no 18 0

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2022.05.20-16:41:23

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