The New Detections of 7Li/6Li Isotopic Ratio in the Interstellar Media
Abstract
We have determined the isotopic abundance ratio of 7Li/6Li in the interstellar media (ISMs) along lines of sight to HD169454 and HD250290 using the High-Dispersion Spectrograph on the Subaru Telescope. We also observed ζ Oph for comparison with previous data. The observed abundance ratios were 7Li/6Li = 8.1+3.6 -1.8 and 6.3+3.0 -1.7 for HD169454 and HD250290, respectively. These values are in reasonable agreement with those observed previously in the solar neighborhood ISMs within ±2σ error bars and are also consistent with our measurement of 7Li/6Li = 7.1+2.9 -1.6 for a cloud along the line of sight to ζ Oph. This is good evidence for homogeneous mixing and instantaneous recycling of the gas component in the Galactic disk. We also discuss several source compositions of 7Li, Galactic cosmic-ray interactions, stellar nucleosynthesis, and big bang nucleosynthesis.
Based on data collected at Subaru Telescope, which is operated by the National Astronomical Observatory of Japan.- Publication:
-
The Astrophysical Journal
- Pub Date:
- August 2009
- DOI:
- 10.1088/0004-637X/701/2/1506
- Bibcode:
- 2009ApJ...701.1506K
- Keywords:
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- ISM: general;
- stars: individual: HD169454 HD250290 ζ Oph