Effective collision strengths improvements on Mg I atomic model for solar and stellar atmospheric models

J. I. PERALTA; M. C. VIEYTES; D. M. MITNIK; M. P. A. MENDEZ

La Laguna, Tenerife

Workshop; XXIX Canary Islands Winter School Of Astrophysics; 2017

Instituto de Astrofísica de Canarias

It is studied the improvement of the atmospheric model 1401 (Fontenla, J. M. et al. 2015, ApJ, 809, 15) by improving the atomic model of the Mg I atom. The atomic models are essential to compute the populations in full NLTE. In this case, changes in the Effective Collision Strength (ECS) parameters for electron impact excitation were made to test influence in the synthetic spectra.Given the relevance of the spectral features formed by Mg I in the stellar spectrum of late type stars, and because there is a need to improve the Mg I atomic model mainly in the NUV range (eg. 283.5 nm inverted line), the populations of the Mg I atom were computed using the Solar-stellar Radiation Physical Modeling (SSRPM) code for 2 new atomic models:* The atomic model to be improved it has its ECS parameters calculated by the Seaton's formula (for allowed transitions) and the van Regemorter's formula (to forbidden transitions).* In the atomic model generated by us, the ECS parameters are calculated using Distorted-wave method.* The second atomic model it uses the ECS calculated by R-matrix method. This calculations are the newest found and were provided by Barklem et al. (2017, A&A 606, A11).For each one of the three atomic models, an atmospheric model with the same thermal structure it is generated. Then it is computed each synthetic spectra to identify and compare the most relevant changes in the formation of Mg I spectral lines over the model (1401) and over the observations.