تقرير
Non-detection of $^6$Li in Spite plateau stars with ESPRESSO
| العنوان: | Non-detection of $^6$Li in Spite plateau stars with ESPRESSO |
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| المؤلفون: | Wang, E. X., Nordlander, T., Asplund, M., Lind, K., Zhou, Y., Reggiani, H. |
| سنة النشر: | 2021 |
| المجموعة: | Astrophysics |
| مصطلحات موضوعية: | Astrophysics - Solar and Stellar Astrophysics, Astrophysics - Astrophysics of Galaxies |
| الوصف: | The detection of $^6$Li in Spite plateau stars contradicts the standard Big Bang nucleosynthesis prediction, known as the second cosmological lithium problem. We measure the isotopic ratio $^6$Li/$^7$Li in three Spite plateau stars: HD 84937, HD 140283, and LP 815-43. We use 3D NLTE radiative transfer and for the first time apply this to high resolution, high-S/N data from the ultra-stable VLT/ESPRESSO spectrograph. These are amongst the best spectra ever taken of any metal-poor stars. As the measurement of $^6$Li/$^7$Li is degenerate with other physical stellar parameters, we employ Markov chain Monte Carlo methods to find the probability distributions of measured parameters. As a test of systematics we also use three different fitting methods. We do not detect $^6$Li in any of the three stars, and find consistent results between our different methods. We estimate 2$\sigma$ upper limits to $^6$Li/$^7$Li of 0.7%, 0.6%, and 1.7% respectively for HD 84937, HD 140283, and LP 815-43. Our results indicate that there is no second cosmological lithium problem, as there is no evidence of $^6$Li in Spite Plateau stars. Comment: 17 pages, 9 figures, accepted for publication in MNRAS |
| نوع الوثيقة: | Working Paper |
| DOI: | 10.1093/mnras/stab2924 |
| URL الوصول: | http://arxiv.org/abs/2110.03822 |
| رقم الأكسشن: | edsarx.2110.03822 |
| قاعدة البيانات: | arXiv |
| DOI: | 10.1093/mnras/stab2924 |
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