| Title |
Theoretical study of Th III energy levels and transitions for applications to kilonova spectra |
| Authors |
Kitovienė, Laima ; Gaigalas, Gediminas ; Rynkun, Pavel ; Domoto, Nanae ; Tanaka, Masaomi ; Kato, Daiji |
| DOI |
10.1093/mnras/staf296 |
| Full Text |
|
| Is Part of |
Monthly notices of the Royal Astronomical Society.. Oxford : Oxford University Press. 2025, vol. 538, iss. 1, p. 92-100.. ISSN 0035-8711. eISSN 1365-2966 |
| Keywords [eng] |
atomic data ; opacity ; neutron star mergers |
| Abstract [eng] |
The neutron star merger is a promising site of heavy element production. By producing heavy elements, the neutron star merger gives rise to a thermal transient called a kilonova. Studying kilonova spectra enables us to quantify the heavy element production. Among the heaviest elements, doubly ionized Thorium (Th, Z = 90) is one of the important candidates for producing detectable absorption features in kilonova spectra. This paper investigates the atomic properties of Th III to provide energy level and transition data. The multiconfiguration Dirac–Hartree–Fock and relativistic configuration interaction methods, which are implemented in the general-purpose relativistic atomic structure package GRASP 2018, are used to compute energy levels of the 5f6d , 6d2 , 7s2 , 5f2 , 6d7s , 5f7p and 5f7s configurations and electric dipole transitions between states of these configurations. The accuracy of energy levels is evaluated by comparing it with experimental data and with various theoretical methods. Our calculated energy levels are consistent with the experimental results with a root mean square deviation of 436 cm −1 . The accuracy of transition data is investigated using the quantitative and qualitative evaluation method. By performing radiative transfer simulations for kilonova spectra with our transition data, we show that kilonova including Th with a mass fraction of (3 −10) ×10 −5 can produce Th III absorption features around 18 000 Å. |
| Published |
Oxford : Oxford University Press |
| Type |
Journal article |
| Language |
English |
| Publication date |
2025 |
| CC license |
|
