2007A&A...471L..41U


C.D.S. - SIMBAD4 rel 1.7 - 2020.05.29CEST03:39:47

2007A&A...471L..41U - Astronomy and Astrophysics, volume 471, L41-45 (2007/8-4)

Low-mass lithium-rich AGB stars in the Galactic bulge: evidence for cool bottom processing?

UTTENTHALER S., LEBZELTER T., PALMERINI S., BUSSO M., ARINGER B. and LEDERER M.T.

Abstract (from CDS):

The stellar production of the light element lithium is still a matter of debate. We report the detection of low-mass, Li-rich Asymptotic Giant Branch (AGB) stars located in the Galactic bulge. A homogeneous and well-selected sample of low mass, oxygen-rich AGB stars in the Galactic bulge has been searched for the absorption lines of Li. Using spectral synthesis techniques, we determine from high resolution UVES/VLT spectra the Li abundance in four out of 27 sample stars, and an upper limit for the remaining stars. Two stars in our sample have a solar Li abundance or above; these stars seem to be a novelty, since they do not show any s-element enhancement. Two more stars have a Li abundance slightly below solar; these stars do show s-element enhancement in their spectra. Different scenarios which lead to an increased Li surface abundance in AGB stars are discussed. Of the different enrichment scenarios presented, Cool Bottom Processing (CBP) is the most likely one for the Li-rich objects identified here. Self-enrichment by Hot Bottom Burning (HBB) seems very unlikely as all Li-rich stars are below the HBB mass limit. Also, the ingestion of a low mass companion into the stars' envelope is unlikely because the associated additional effects are lacking. Mass transfer from a former massive binary companion is a possible scenario, if the companion produced little s-process elements. A simple theoretical estimation for the Li abundance due to CBP is presented and compared to the observed values.

Abstract Copyright:

Journal keyword(s): nuclear reactions, nucleosynthesis abundances - stars: AGB and post-AGB - stars: evolution - stars: abundances

Errata: erratum vol. 478, p. 527 (2008)

Status at CDS:  

Simbad objects: 15

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Number of rows : 15

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 NAME SMC G 00 52 38.0 -72 48 01   2.79 2.2     ~ 9384 1
2 SV* HV 1645 Mi* 00 55 19.7749218687 -73 14 42.419576670   20.10 16.84   14.39 ~ 15 0
3 NAME Magellanic Clouds GrG 03 00 -71.0           ~ 5614 1
4 V* NO Aur s*r 05 40 42.0501780592 +31 55 14.202295199 10.52 8.30 6.21 4.43 3.02 M2Iab 135 1
5 V* V2652 Sgr Mi* 18 12 48.4992378721 -33 19 26.881226835           ~ 8 0
6 V* V3117 Sgr Mi* 18 21 32.4908620204 -36 07 35.070033836           ~ 9 0
7 V* V3252 Sgr Mi* 18 24 28.0181340952 -32 30 51.534569952           ~ 7 0
8 V* V3375 Sgr Mi* 18 28 08.9794165199 -36 31 25.988243381           ~ 8 0
9 V* V3537 Sgr Mi* 18 33 06.1544464247 -36 22 26.861591269       13.42   ~ 6 0
10 V* V2017 Sgr Mi* 18 38 45.6634767800 -34 33 28.003218421           S: 15 0
11 V* WX Cyg C* 20 18 33.2743243024 +37 26 59.076638818   12.95 8.80     C-J6 122 0
12 V* V441 Cyg S* 20 27 08.1155249428 +36 33 06.493962762   12.04 9.80     S4,6 41 0
13 * pi.01 Gru S* 22 22 44.20571 -45 56 52.6115 10.52 8.62 6.55 3.19 0.52 S5,7: 159 1
14 V* HR Peg S* 22 54 35.6271949429 +16 56 30.599214359 9.970 8.160 6.360     S4+/1+ 124 0
15 NAME Galactic Bulge reg ~ ~           ~ 3363 0

    Equat.    Gal    SGal    Ecl

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2020.05.29-03:39:47

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