2004A&A...428L...9P


Query : 2004A&A...428L...9P

2004A&A...428L...9P - Astronomy and Astrophysics, volume 428, L9-12 (2004/12-2)

Lead abundance in the uranium star CS31082-001.

PLEZ B., HILL V., CAYREL R., SPITE M., BARBUY B., BEERS T.C., BONIFACIO P., PRIMAS F. and NORDSTROEM B.

Abstract (from CDS):

In a previous paper we were able to measure the abundance of uranium and thorium in the very-metal poor halo giant BPS CS31082-001, but only obtained an upper limit for the abundance of lead (Pb). We have got from ESO 17 h of additional exposure on this star in order to secure a detection of the minimum amount of lead expected to be present in CS31082-001, the amount arising from the decay of the original content of Th and U in the star. We report here this successful detection. We find an LTE abundance log(Pb/H)+12=-0.55±0.15dex, one dex below the upper limits given by other authors for the similar stars CS22892-052 and BD+17°3248, also enhanced in r-process elements. From the observed present abundances of Th and U in the star, the expected amount of Pb produced by the decay of 232Th, and 238U alone, over 12-15Gyr is -0.73±0.17dex. The decay of 235U is more difficult to estimate, but is probably slightly below the contribution of 238U, making the contribution of the 3 actinides only slightly below, or even equal to, the measured abundance. The contribution from the decay of 234U has was not included, for lack of published data. In this sense our determination is a lower limit to the contribution of actinides to lead production. We comment this result, and we note that if a NLTE analysis, not yet possible, doubles our observed abundance, the decay of the 3 actinides will still represent 50 per cent of the total lead, a proportion higher than the values considered so far in the literature.

Abstract Copyright:

Journal keyword(s): stars: abundances - physical data and processes: nuclear reactions, nucleosynthesis, abundances - atomic data

Simbad objects: 4

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Number of rows : 4
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 BD-16 251 RG* 01 29 31.1311443552 -16 00 45.495314460 12.527 12.427 11.642 11.189 10.713 CEMP 288 0
2 HD 115444 Pe* 13 16 42.4590842616 +36 22 52.692135420   9.77 8.97 8.3 7.88 G9V 242 0
3 BD+17 3248 HB* 17 28 14.4690179544 +17 30 35.847574776   10.02 9.34     KIIvw 222 0
4 BPS CS 22892-0052 Pe* 22 17 01.6558764360 -16 39 27.051026544   14.03 13.20 13.06 12.19 KIIvw 444 0

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