2013ApJ...768L..13P


C.D.S. - SIMBAD4 rel 1.7 - 2021.06.19CEST01:51:07

2013ApJ...768L..13P - Astrophys. J., 768, L13 (2013/May-1)

Molybdenum, ruthenium, and the heavy r-process elements in moderately metal-poor main-sequence turnoff stars.

PETERSON R.C.

Abstract (from CDS):

The ratios of elemental abundances observed in metal-poor stars of the Galactic halo provide a unique present-day record of the nucleosynthesis products of its earliest stars. While the heaviest elements were synthesized by the r- and s-processes, dominant production mechanisms of light trans-ironic elements were obscure until recently. This work investigates further our 2011 conclusion that the low-entropy regime of a high-entropy wind (HEW) produced molybdenum and ruthenium in two moderately metal-poor turnoff stars that showed extreme overabundances of those elements with respect to iron. Only a few, rare nucleosynthesis events may have been involved. Here we determine abundances for Mo, Ru, and other trans-Fe elements for 28 similar stars by matching spectral calculations to well-exposed near-UV Keck HIRES spectra obtained for beryllium abundances. In each of the 26 turnoff stars with Mo or Ru line detections and no evidence for s-process production (therefore old), we find Mo and Ru to be three to six times overabundant. In contrast, the maximum overabundance is reduced to factors of three and two for the neighboring elements zirconium and palladium. Since the overproduction peaks sharply at Mo and Ru, a low-entropy HEW is confirmed as its origin. The overabundance level of the heavy r-process elements varies significantly, from none to a factor of four, but is uncorrelated with Mo and Ru overabundances. Despite their moderate metallicity, stars in this group trace the products of different nucleosynthetic events: possibly very few events, possibly events whose output depended on environment, metallicity, or time.

Abstract Copyright:

Journal keyword(s): Galaxy: halo - nuclear reactions, nucleosynthesis, abundances - stars: abundances - stars: Population II

Simbad objects: 30

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Number of rows : 30

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 BD-17 484 PM* 02 31 25.7658698295 -16 59 05.047040170   10.890 10.470 10.159 9.871 F0Vwl 66 0
2 HD 284248 PM* 04 14 35.5161833236 +22 21 04.254015290 9.49 9.68 9.23 8.77 8.43 sdG0 172 0
3 HD 31128 PM* 04 52 09.9097489102 -27 03 50.940327190   9.55 9.14     F3/5Vw 125 0
4 HD 241253 PM* 05 09 56.9590196910 +05 33 26.743378965   10.24   9.4   G0 89 0
5 Ross 49 ** 05 44 56.8112601600 +09 14 32.131302983   12.49 11.75 11.61   sdF6 60 0
6 BD+58 876 ** 05 57 28.5808850435 +58 40 48.776609280       10.2   F8 33 0
7 BD+37 1458 PM* 06 16 01.5222776277 +37 43 18.756795213 9.41 9.52 8.92 8.34 7.91 G0 129 0
8 G 192-43 PM* 06 47 44.9355583602 +58 38 34.534478265   10.75   10.1   F2 63 0
9 G 113-9 PM* 08 00 50.4191757523 -04 05 32.108960537   11.573 10.980 10.689 10.418 ~ 16 0
10 HD 233511 PM* 08 19 22.5717671718 +54 05 09.627780721 10.02 10.24   9.4   F4 127 0
11 G 115-49 PM* 09 05 16.6832497318 +38 47 54.596247670   12.10   11.2   F7 49 0
12 HD 94028 PM* 10 51 28.1254469804 +20 16 38.965521484 8.51 8.69 8.22 7.82 7.54 F8 339 0
13 BD+36 2165 PM* 11 12 48.0000186001 +35 43 43.887345184 9.98 10.19 9.76 9.34 9.02 G0 126 0
14 BD+51 1696 PM* 11 46 35.1557706721 +50 52 54.682692534 10.32 10.47   9.5   sdG0 137 0
15 HD 106038 PM* 12 12 01.3690548563 +13 15 40.620671155 10.45 10.630 10.162 9.851 9.539 F6wl 177 0
16 HD 108177 PM* 12 25 34.9568983381 +01 17 02.259993860 9.87 10.09 9.66 9.21 8.89 F0V 238 0
17 Wolf 550 SB* 14 50 07.8015005617 +00 50 27.177034317   11.47   10.8   sd:F5 74 0
18 BD+42 2667 PM* 16 03 13.2989292029 +42 14 46.649595940   10.33   9.6   F5 137 0
19 HD 160617 PM* 17 42 49.3235999900 -40 19 15.505712142   9.18 8.73 8.394 8.065 G0 188 0
20 BD-08 4501 PM* 17 47 27.9713460047 -08 46 47.733691581   11.18 10.59     sdF8 115 0
21 HD 161770 PM* 17 47 46.0757888339 -09 36 18.444031860 10.38 10.39 9.71 9.04 8.55 F3V 91 0
22 BD+13 3683 SB* 18 33 16.8451410333 +13 09 25.490354259   11.19   10.0   F5 96 0
23 HD 188510 PM* 19 55 09.6783577203 +10 44 27.395091177 9.30 9.41   8.5   G5V: 239 0
24 BD+42 3607 PM* 20 09 01.4133036647 +42 51 54.929695847       9.9   F3 80 0
25 HD 345957 PM* 20 10 48.1626273226 +23 57 54.507927464   9.36   8.6   G0V: 134 0
26 HD 194598 PM* 20 26 11.9185966774 +09 27 00.429262518 8.62 8.82 8.34 7.90 7.56 F8 291 0
27 BD+04 4551 PM* 20 48 50.7247200687 +05 11 58.817666311   10.13 9.67 9.61   F7Vw 72 0
28 BD+26 4251 PM* 21 43 57.1238901563 +27 23 23.991146537       9.9   F6 78 0
29 BD+17 4708 SB* 22 11 31.3751899315 +18 05 34.158392398 9.73 9.91 9.46 9.03 8.70 sdF8 545 0
30 BD+07 4841 PM* 22 18 36.5061308735 +08 26 44.960669943   10.84   10.1   G0 104 0

    Equat.    Gal    SGal    Ecl

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2021.06.19-01:51:07

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