A numerical approach for modelling the polarisation signals of strong resonance lines with partial frequency redistribution - Applications to two-term atoms and plane-parallel atmospheres

Home

All issues

Volume 699 (July 2025)

A&A, 699 (2025) A233

Full HTML

Open Access

Table 1

Atomic parameters for the Mg II h&k doublet and the H I Ly-α line.

Ion	M (AU)	Ground state	Line	Upper state	E_u (cm⁻¹)	4 (Å)	A_u_𝓁 (s⁻¹)
Mg II	24.305	3s ²S_1/2	h	$3 p^{2} P_{1 / 2}^{0}$ $3\frame{p^2}\frame{\text{P}}_\frame{1/2}^0$	35 669.31	2803.531	2.57 × 10⁸

			k	$3 p^{2} P_{3 / 2}^{0}$ $3\frame{p^2}\frame{\text{P}}_\frame{3/2}^0$	35760.88	2796.352	2.60 × 10⁸

H I	1.008	1s ²S_1/2	Ly-α	$2 p^{2} P_{1 / 2}^{0}$ $2\frame{p^2}\frame{\text{P}}_\frame{1/2}^0$	82 258.92	1215.674	6.265 × 10⁸

				$2 p^{2} P_{3 / 2}^{0}$ $2\frame{p^2}\frame{\text{P}}_\frame{3/2}^0$	82 259.29	1215.668	6.265 × 10⁸

Notes. Data from Kramida et al. (2023). The quantities E_u and λ denote the energy of the upper state and the line-centre wavelength in vacuum, respectively. For both ions, the energy of the ground state is E_ℓ = 0. The Einstein coefficients for spontaneous emission from the upper to the lower term of the considered atomic models were obtained as the average of the experimental Einstein coefficients for the fine-structure components of each multiplet, weighted by the statistical weights of the corresponding upper J-levels (see Eq. (1) in del Pino Alemán et al. 2020). For the Mg II h&k doublet, we thus used A_uℓ = 2.59 × 10⁸ s⁻¹, whereas for the H I Ly-α line we used A_uℓ = 6.265 × 10⁸ s⁻¹.

Current usage metrics show cumulative count of Article Views (full-text article views including HTML views, PDF and ePub downloads, according to the available data) and Abstracts Views on Vision4Press platform.

Data correspond to usage on the plateform after 2015. The current usage metrics is available 48-96 hours after online publication and is updated daily on week days.

Initial download of the metrics may take a while.