2007A&A...469..265T


C.D.S. - SIMBAD4 rel 1.7 - 2020.08.08CEST18:07:56

2007A&A...469..265T - Astronomy and Astrophysics, volume 469, 265-274 (2007/7-1)

Is 6Li in metal-poor halo stars produced in situ by solar-like flares?

TATISCHEFF V. and THIBAUD J.-P.

Abstract (from CDS):

The high 6Li abundances recently measured in metal-poor halo stars are far above the value predicted by Big Bang nucleosynthesis. They cannot be explained by galactic cosmic-ray interactions in the interstellar medium either. Various pre-galactic sources of 6Li have been proposed in the literature. We study the possibility that the observed 6Li was produced by repeated solar-like flares on the main sequence of these low-metallicity stars. The time-dependent flaring activity of these objects is estimated from the observed evolution of rotation-induced activity in Pop I dwarf stars. As in solar flares, 6Li could be mainly created in interactions of flare-accelerated 3He with stellar atmospheric 4He, via the reaction 4He(3He,p)6Li. Stellar dilution and destruction of flare-produced 6Li are evaluated from the evolutionary models of metal-poor stars developed by Richard and co-workers. Stellar depletion should be less important for 6Li atoms synthesized in flares than for those of protostellar origin. Theoretical frequency distributions of 6Li/7Li ratios are calculated using a Monte-Carlo method and compared with the observations. Excellent agreement is found with the measured 6Li/7Li distribution, when taking into account the contribution of protostellar 6Li originating from galactic cosmic-ray nucleosynthesis. We propose as an observational test of the model to seek for a positive correlation between 6Li/7Li and stellar rotation velocity. We also show that the amounts of 7Li, Be and B produced in flares of metal-poor halo stars are negligible as compared with the measured abundances of these species. 6Li in low-metallicity stars may be a unique evidence of the nuclear processes occuring in stellar flares.

Abstract Copyright:

Journal keyword(s): stars: abundances - stars: flare - nuclear reactions, nucleosynthesis, abundances

Simbad objects: 13

goto Full paper

goto View the reference in ADS

Number of rows : 13

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 19445 PM* 03 08 25.5884 +26 19 51.400 8.29 8.52 8.06 7.60 7.27 G2VFe-3 741 0
2 Cl Melotte 20 OpC 03 26 42 +48 48.0           ~ 752 0
3 Cl Melotte 22 OpC 03 47 00 +24 07.0           ~ 2990 0
4 NAME Orion Nebula Cluster OpC 05 35.0 -05 29           ~ 1988 1
5 M 42 HII 05 35 17.3 -05 23 28           ~ 3732 0
6 NGC 2264 OpC 06 40 58 +09 53.7     3.9     ~ 1593 1
7 HD 74000 PM* 08 40 50.8038415228 -16 20 42.513275817 9.84 10.09 9.66     F2 243 0
8 BD+09 2190 PM* 09 29 15.5616421382 +08 38 00.469417390   11.54   10.8   sdA5 115 0
9 HD 84937 PM* 09 48 56.09801 +13 44 39.3237 8.49 8.68 8.32 7.97 7.70 F8Vm-5 718 0
10 IC 2602 OpC 10 42 58 -64 24.0           ~ 551 0
11 HD 106038 PM* 12 12 01.3690548564 +13 15 40.620671155 10.45 10.630 10.162 9.851 9.539 F6wl 169 0
12 BD+42 2667 PM* 16 03 13.2989292029 +42 14 46.649595940   10.33   9.6   F5 131 0
13 BD+20 3603 PM* 17 54 43.2306261669 +20 16 16.443521966   10.13   9.6   F0 146 0

    Equat.    Gal    SGal    Ecl

To bookmark this query, right click on this link: simbad:objects in 2007A&A...469..265T and select 'bookmark this link' or equivalent in the popup menu


2020.08.08-18:07:56

© Université de Strasbourg/CNRS

    • Contact