2011A&A...536A..40A


C.D.S. - SIMBAD4 rel 1.7 - 2020.10.30CET03:28:04

2011A&A...536A..40A - Astronomy and Astrophysics, volume 536A, 40-40 (2011/12-1)

CNO and f abundances in the barium star HD 123396.

ALVES-BRITO A., KARAKAS A.I., YONG D., MELENDEZ J. and VASQUEZ S.

Abstract (from CDS):

Barium stars are moderately rare, chemically peculiar objects, which are believed to be the result of the pollution of an otherwise normal star by material from an evolved companion on the asymptotic giant branch (AGB). We aim to derive carbon, nitrogen, oxygen, and fluorine abundances for the first time from the infrared spectra of the barium red giant star HD 123396 to quantitatively test AGB nucleosynthesis models for producing barium stars via mass accretion. High-resolution and high S/N infrared spectra were obtained using the Phoenix spectrograph mounted at the Gemini South telescope. The abundances were obtained through spectrum synthesis of individual atomic and molecular lines, using the MOOG stellar line analysis program, together with Kurucz's stellar atmosphere models. The analysis was classical, using 1D stellar models and spectral synthesis under the assumption of local thermodynamic equilibrium. We confirm that HD 123396 is a metal-deficient barium star ([Fe/H]=-1.05), with A(C)=7.88, A(N)=6.65, A(O)=7.93, and A(Na)=5.28 on a logarithmic scale where A(H)=12, leading to [(C+N)/Fe]≃0.5. The A(CNO) group, as well as the A(Na) abundances, is in excellent agreement with those previously derived for this star using high-resolution optical data. We also found A(F)=4.16, which implies [F/O]=0.39, a value that is substantially higher than the F abundances measured in globular clusters of a similar metallicity, noting that there are no F measurements in field stars of comparable metallicity. The observed abundance pattern of the light elements (CNO, F, and Na) recovered here as well as the heavy elements (s-process) studied elsewhere suggest that the surface composition of HD 123396 is well fitted by the predicted abundance pattern of a 1.5M AGB model star with Z=0.001. Thus, the AGB mass transfer hypothesis offers a quantitatively viable framework.

Abstract Copyright:

Journal keyword(s): stars: AGB and post-AGB - stars: abundances - nuclear reactions, nucleosynthesis, abundances - stars: atmospheres - stars: individual: HD 123396 (HIP 69834)

Simbad objects: 9

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Number of rows : 9

N Identifier Otype ICRS (J2000)
RA
ICRS (J2000)
DEC
Mag U Mag B Mag V Mag R Mag I Sp type #ref
1850 - 2020
#notes
1 HD 16458 Pe* 02 47 47.7322966372 +81 26 54.517420201   7.091 5.781     K1Ba5 152 0
2 V* HR CMa Al* 06 32 46.8721481683 -11 09 58.968732064 8.12 7.35 6.24 5.49 5.01 G9III:Ba3.5 168 0
3 HD 121447 Pe* 13 55 46.9649688947 -18 14 56.480134690 11.50 9.61 7.80     C2,1_CH4:_Ba4 117 0
4 * alf Boo RG* 14 15 39.67207 +19 10 56.6730 2.46 1.18 -0.05 -1.03 -1.68 K1.5IIIFe-0.5 2148 0
5 HD 123396 Pe* 14 17 31.5591919267 -83 32 52.136247808   10.14 8.96     G8/K0II/IIIp 32 0
6 M 4 GlC 16 23 35.22 -26 31 32.7           ~ 1685 0
7 NGC 6712 GlC 18 53 04.32 -08 42 21.5   9.85 8.69     ~ 470 0
8 HD 178717 SB* 19 09 22.0092372317 +10 14 28.243016839   9.05 7.14     K3.5III:Ba4+ 107 0
9 * zet Cap SB* 21 26 40.0263390 -22 24 40.804197 5.35 4.75 3.74 3.09 2.65 G4Ib:Ba2 267 1

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2020.10.30-03:28:04

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