2007A&A...468..679S


Query : 2007A&A...468..679S

2007A&A...468..679S - Astronomy and Astrophysics, volume 468, 679-693 (2007/6-3)

Abundance analysis of barium and mild barium stars.

SMILJANIC R., PORTO DE MELLO G.F. and DA SILVA L.

Abstract (from CDS):

We compare and discuss abundances and trends in normal giants, mild barium, and barium stars, searching for differences and similarities between barium and mild barium stars that could help shed some light on the origin of these similar objects. Also, we search for nucleosynthetic effects possibly related to the s-process that were observed in the literature for elements like Cu in other types of s-process enriched stars. High signal to noise, high resolution spectra were obtained for a sample of normal, mild barium, and barium giants. Atmospheric parameters were determined from the FeI and FeII lines. Abundances for Na, Mg, Al, Si, Ca, Sc, Ti, V, Cr, Mn, Fe, Co, Ni, Cu, Zn, Sr, Y, Zr, Ba, La, Ce, Nd, Sm, Eu, and Gd, were determined from equivalent widths and model atmospheres in a differential analysis, with the red giant ε Vir as the standard star. The different levels of s-process overabundances of barium and mild barium stars were earlier suggested to be related to the stellar metallicity. Contrary to this suggestion, we found in this work no evidence of barium and mild barium having a different range in metallicity. However, comparing the ratio of abundances of heavy to light s-process elements, we found some evidence that they do not share the same neutron exposure parameter. The exact mechanism controlling this difference is still not clear. As a by-product of this analysis we identify two normal red giants misclassified as mild barium stars. The relevance of this finding is discussed. Concerning the suggested nucleosynthetic effects possibly related to the s-process, for elements like Cu, Mn, V and Sc, we found no evidence for an anomalous behavior in any of the s-process enriched stars analyzed here. However, further work is still needed since a clear [Cu/Fe] vs. [Ba/Fe] anticorrelation exists for other s-process enriched objects.

Abstract Copyright:

Journal keyword(s): stars: abundances - stars: chemically peculiar - stars: late-type

Simbad objects: 17

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Number of rows : 17
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 * del Phe PM* 01 31 15.1047497 -49 04 21.730837   4.918 3.935     G8.5IIIb 116 0
2 * ksi01 Cet EB* 02 12 59.9976927035 +08 50 48.202315944 5.86 5.23 4.35 3.68 3.18 G7IIIBa0.4Fe-1 207 1
3 HD 20894 * 03 21 24.0043600176 -23 38 06.552850356   6.381 5.496     G7IIbCN-1Hdel-1 69 0
4 * alf Hor PM* 04 14 00.1144482 -42 17 39.723208 5.97 4.96 3.86 3.00 2.41 K2III 136 0
5 HD 26886 SB* 04 14 58.8384003717 -00 59 50.785904491   8.91 7.99     G8II/III 35 0
6 V* HR CMa EB* 06 32 46.8721481683 -11 09 58.968732064 8.12 7.35 6.24 5.49 5.01 G9III:Ba3.5 171 0
7 HD 50082 SB* 06 51 53.9593511415 +06 36 24.508450962   8.46 7.42     K0_Ba3 53 1
8 * omi Vir PM* 12 05 12.5404884 +08 43 58.749788 5.75 5.11 4.12 3.38 2.89 G8IIICN0.5CH1Ba1 273 0
9 * eps Vir PM* 13 02 10.5978496 +10 57 32.941443 4.45 3.71 2.79 2.16 1.71 G8III-IIIb 532 0
10 HD 116713 Pe* 13 26 07.7990298136 -39 45 18.456410720 7.31 6.29 5.09     K0.5IIIbBa3 133 0
11 * 16 Ser SB* 15 36 29.5749786777 +10 00 36.557426427   6.217 5.253     K0III:CN1Ba0.7Sr2 200 0
12 HD 147513 PM* 16 24 01.2905970257 -39 11 34.734611237 6.17 6.02 5.376     G5V 321 1
13 * 24 Aql * 19 18 50.9477701171 +00 20 20.544756454   7.454 6.404 7.29   K0-IIIa:CH1Ba0.5 52 0
14 * zet Cyg SB* 21 12 56.1859347 +30 13 36.895667 4.96 4.20 3.21 2.52 2.04 G8+III-IIIaBa0.5 328 0
15 * zet Cap SB* 21 26 40.0263390 -22 24 40.804197 5.35 4.75 3.74 3.09 2.65 G4Ib:Ba2 271 1
16 HD 205011 SB* 21 31 50.1440984214 +23 50 42.551089035   7.50 6.42     G9+IIIaBa1+ 71 0
17 * 7 Psc PM* 23 20 20.5830620142 +05 22 52.700020565   6.262 5.069     K1IV 113 0

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2021.12.01-11:45:11

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