Beryllium abundances of solar-analog stars

Y Takeda, A Tajitsu, S Honda… - Publications of the …, 2011 - academic.oup.com
Y Takeda, A Tajitsu, S Honda, S Kawanomoto, H Ando, T Sakurai
Publications of the Astronomical Society of Japan, 2011academic.oup.com
An extensive Be abundance analysis was conducted for 118 solar analogs (along with 87
FGK standard stars) by applying the spectrum synthesis technique to the near-UV region
comprising the Be ii line at 3131.066 Å, in an attempt to investigate whether Be suffers any
depletion, such as in the case of Li showing a large diversity. We found that, while most of
these Sun-like stars are superficially similar in terms of their (Be)(Be abundances) around
the solar value within 0.2 dex, 4 out of 118 samples turned out to be strikingly Be-deficient …
Abstract
An extensive Be abundance analysis was conducted for 118 solar analogs (along with 87 FGK standard stars) by applying the spectrum synthesis technique to the near-UV region comprising the Be II line at 3131.066 Å, in an attempt to investigate whether Be suffers any depletion, such as in the case of Li showing a large diversity. We found that, while most of these Sun-like stars are superficially similar in terms of their (Be) (Be abundances) around the solar value within 0.2 dex, 4 out of 118 samples turned out to be strikingly Be-deficient (by more than 2 dex), and these 4 stars belong to the group of lowest sin (projected rotation velocity). Moreover, even for the other majority showing an apparent similarity in Be, we can recognize a tendency that (Be) gradually increases with an increase in sin . These observational facts suggest that any solar analog star (including the Sun) generally suffers some kind of Be depletion during their lives, where the rotational velocity (or the angular momentum) plays an important role in the sense that the depletion tends to be enhanced by slower rotation. Hence, our findings require that the occasionally stated view “G-type dwarfs with 6000 K are essentially homogeneous in Be with their original composition retained” should be revised. Also, our analysis indicates that the difference of 0.2 dex in (Be) between the solar photosphere and the meteorite really exists, implying that the “UV missing opacity” is irrelevant at least for this Be II line.
Oxford University Press