2006A&A...451..651J


C.D.S. - SIMBAD4 rel 1.7 - 2021.03.05CET02:40:26

2006A&A...451..651J - Astronomy and Astrophysics, volume 451, 651-670 (2006/5-4)

The Hamburg/ESO R-process enhanced star survey (HERES). III. HE 0338-3945 and the formation of the r + s stars.

JONSELL K., BARKLEM P.S., GUSTAFSSON B., CHRISTLIEB N., HILL V., BEERS T.C. and HOLMBERG J.

Abstract (from CDS):

We have derived abundances of 33 elements and upper limits for 6 additional elements for the metal-poor ([Fe/H]=-2.42) turn-off star HE 0338-3945 from high-quality VLT-UVES spectra. The star is heavily enriched, by about a factor of 100 relative to iron and the Sun, in the heavy s-elements (Ba, La, ...). It is also heavily enriched in Eu, which is generally considered an r-element, and in other similar elements. It is less enriched, by about a factor of 10, in the lighter s-elements (Sr, Y and Zr). C is also strongly enhanced and, to a somewhat lesser degree, N and O. These abundance estimates are subject to severe uncertainties due to NLTE and thermal inhomogeneities which are not taken into detailed consideration. However, an interesting result, which is most probably robust in spite of these uncertainties, emerges: the abundances derived for this star are very similar to those of other stars with an overall enhancement of all elements beyond the iron peak. We have defined criteria for this class of stars, r+s stars, and discuss nine different scenarios to explain their origin. None of these explanations is found to be entirely convincing. The most plausible hypotheses involve a binary system in which the primary component goes through its giant branch and asymptotic giant branch phases and produces CNO and s-elements which are dumped onto the observed star. Whether the r-element Eu is produced by supernovae before the star was formed (perhaps triggering the formation of a low-mass binary), by a companion as it explodes as a supernova (possibly triggered by mass transfer), or whether it is possibly produced in a high-neutron-density version of the s-process is still unclear. Several suggestions are made on how to clarify this situation.

Abstract Copyright:

Journal keyword(s): stars: populationii - stars: fundamental parameters - stars: abundances - Galaxy: halo - Galaxy: abundances - Galaxy: evolution

Simbad objects: 44

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Number of rows : 44

N Identifier Otype ICRS (J2000)
RA
ICRS (J2000)
DEC
Mag U Mag B Mag V Mag R Mag I Sp type #ref
1850 - 2021
#notes
1 HE 0024-2523 Pe* 00 27 27.6485410349 -25 06 28.291081599 15.067 15.32 14.91     CEMP-s 65 0
2 BPS CS 29497-0004 Pe* 00 28 06.9155330651 -26 03 04.268822971   14.76 14.07 13.583 13.116 ~ 44 0
3 BPS CS 31062-0050 Pe* 00 30 31.0633474070 -12 05 10.873150611   13.7 13.05 12.681 12.309 CEMP-r/s 60 0
4 CD-24 266 BS* 00 40 47.9313778053 -24 07 34.183052519   12.955 12.656 12.441 12.216 CEMP-s 90 0
5 SKB 2 Pe* 00 41 39.8197261334 -26 18 54.463949137   13.338 12.221 11.704 11.321 CEMP-s 84 0
6 SB 960 Pe* 00 44 03.5698517387 -13 55 26.270588506   12.69 12.15 11.806 11.483 CEMP-s 104 0
7 CD-26 304 Pe* 00 57 18.1376089543 -25 26 09.699477820   13.57 12.69 12.198 11.759 CEMP-s 64 1
8 HE 0058-0244 Pe* 01 00 53.0236506123 -02 28 19.948243997   14.42 13.73 13.331 12.942 CEMP-r/s 34 0
9 BPS CS 22183-0031 Pe* 01 09 05.0899437519 -04 43 21.344131594   14.24 13.62 13.178 12.724 ~ 40 0
10 BPS CS 31082-0001 Pe* 01 29 31.1311330115 -16 00 45.496485322 12.527 12.427 11.642 11.189 10.713 CEMP 250 0
11 HE 0131-3953 Pe* 01 33 36.4629589511 -39 37 52.151224348     15.979   15.323 CEMP-s 21 0
12 HE 0202-2204 Pe* 02 04 50.0173132195 -21 50 10.475032504     15.375   14.575 ~ 19 0
13 HD 13979 Pe* 02 15 20.8534621275 -25 54 54.874562581   9.81 9.18     F/Gw 81 0
14 BPS CS 29526-0110 Pe* 03 27 43.6395462631 -23 00 29.931204041   13.71 13.35 13.116 12.834 CEMP-r/s 47 0
15 HE 0338-3945 Pe* 03 39 55.0065616032 -39 35 42.904334997   15.753 15.333 15.098 14.787 CEMP-r/s 34 0
16 HD 25532 HB* 04 04 11.0094160821 +23 24 27.103630928   8.87 8.24     F6IV-V 114 0
17 HE 0430-4901 Pe* 04 31 31.1370355491 -48 54 41.519418507     14.572   13.770 CEMP-s 13 0
18 HE 0432-0923 Pe* 04 34 25.6711776469 -09 16 50.513666136     15.165   14.140 ~ 13 0
19 HE 1046-1352 Pe* 10 48 29.9237884759 -14 08 11.827506657   15.390 14.714 14.309 13.879 CEMP-s 9 0
20 HE 1105+0027 Pe* 11 07 49.5058676910 +00 11 38.347372568   16.038 15.646 15.358 15.018 CEMP-s 23 0
21 HE 1127-1143 Pe* 11 29 50.6276751880 -12 00 12.580350655     15.885 15.434 15.002 ~ 12 0
22 HE 1135+0139 Pe* 11 38 09.8531116311 +01 22 44.046134820   16.322 15.829 15.484 15.084 CEMP-s 18 0
23 HD 105546 HB* 12 09 02.7215214809 +59 01 05.137542058   9.27 8.61 8.29   G2III: 107 0
24 HE 1219-0312 Pe* 12 21 34.1430157283 -03 28 39.635608057     15.940   15.043 ~ 33 0
25 HD 115444 Pe* 13 16 42.4591800169 +36 22 52.695481224   9.77 8.97 8.3 7.88 G9V 229 0
26 EPIC 212685903 Pe* 14 07 42.9726133296 -08 36 14.381851613   14.770 13.998 13.591 13.171 CEMP-s 11 0
27 BPS CS 30301-0015 Pe* 15 08 56.8433023195 +02 30 18.628172611   14.04 13.04   12.063 CEMP-s 44 0
28 BPS CS 30306-0132 Pe* 15 14 18.9190922462 +07 27 02.682876503   13.62 12.73 12.421 11.948 ~ 30 0
29 BD+11 2998 HB* 16 30 16.7822979350 +10 59 51.751912668   9.73 9.10     F8 75 0
30 LP 625-44 Pe* 16 43 14.0364804654 -01 55 30.408914037   12.84 11.68     CEMP-s 102 0
31 M 92 GlC 17 17 07.39 +43 08 09.4     6.52     ~ 1934 0
32 BD+17 3248 HB* 17 28 14.4691668039 +17 30 35.848406966   10.02 9.34     KIIvw 202 0
33 HD 166161 PM* 18 09 40.6841408875 -08 46 45.602722086 9.53 9.13 8.16     G0wF0 133 0
34 HD 196944 Pe* 20 40 46.0790261041 -06 47 50.650812411   9.01 8.40 8.08   CEMP-s 90 0
35 BPS CS 22880-0074 Pe* 20 46 03.2162078511 -20 59 14.111093923   13.84 13.27 12.770 12.382 CEMP-s 45 0
36 BPS CS 22898-0027 Pe* 21 05 45.0995574992 -18 36 57.505496795   13.26 12.76 12.476 12.094 CEMP-r/s 80 0
37 HE 2134-3940 Pe* 21 37 45.7673672486 -39 27 22.314122762   13.790 12.660 12.160 11.760 KIIvw 82 0
38 HE 2148-1247 Pe* 21 51 17.9099257554 -12 33 41.560711332   15.2 14.79     CEMP-r/s 43 0
39 BPS CS 22881-0036 Pe* 22 07 58.4409012147 -40 44 16.477797121   14.42 13.95 13.633 13.278 CEMP-s 35 0
40 BPS CS 22892-0052 Pe* 22 17 01.6558480594 -16 39 27.051900047   14.03 13.20 13.06 12.19 KIIvw 418 0
41 HE 2224+0143 Pe* 22 27 23.1215444901 +01 58 33.065892787   14.54 13.83 13.208 12.733 ~ 19 0
42 BPS CS 29491-0069 Pe* 22 31 02.1859200260 -32 38 36.527997357   13.72 13.09 12.654 12.175 ~ 27 0
43 HD 218857 PM* 23 11 24.5948588495 -16 15 04.029541995   9.60 8.95     G5/8w(a) 104 0
44 HE 2327-5642 Pe* 23 30 37.0896402813 -56 26 14.384633079   14.590 13.881 13.425 12.948 ~ 29 0

    Equat.    Gal    SGal    Ecl

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2021.03.05-02:40:26

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