Detection of cesium in the atmosphere of the hot He-rich white dwarf HD 149499B
| Autor: | Chayer, P., Mendoza, C., Meléndez, M., Deprince, J., Dupuis, J. |
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| Rok vydání: | 2022 |
| Předmět: | |
| Druh dokumentu: | Working Paper |
| DOI: | 10.1093/mnras/stac3138 |
| Popis: | We report the first detection of cesium (Z = 55) in the atmosphere of a white dwarf. Around a dozen absorption lines of Cs IV, Cs V, and Cs VI have been identified in the Far Ultraviolet Spectroscopic Explorer spectrum of the He-rich white dwarf HD 149499B (Teff = 49,500 K, log g = 7.97). The lines have equivalent widths ranging from 2.3 to 26.9 m\r{A}. We performed a spectral synthesis analysis to determine the cesium content in the atmosphere. Non-LTE atmosphere models were computed by considering cesium explicitly in the calculations. For this purpose we calculated oscillator strengths for the bound-bound transitions of Cs IV-Cs VI with both AUTOSTRUCTURE (multiconfiguration Breit-Pauli) and GRASP2K (multiconfiguration Dirac-Fock) atomic structure codes as neither measured nor theoretical values are reported in the literature. We determined a cesium abundance of log N(Cs)/N(He) = -5.45(0.35), which can also be expressed in terms of the mass fraction log X(Cs) = -3.95(0.35). Comment: 28 pages, 2 figures, accepted for publication in Monthly Notices of the Royal Astronomical Society |
| Databáze: | arXiv |
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