Fast methods for tracking grain coagulation and ionization

II. Extension to thermal ionization

¹ Institut de Recherche en Astrophysique et Planétologie, Université Paul, Sabatier Toulouse 3, 118 Rte de Narbonne, 31062 Toulouse, France
² Department of Astrophysics, American Museum of Natural History, Central Park West at 79th Street, New York, NY 10024, USA
e-mail: pierre.marchand.astr@gmail.com
³ Université Paris-Saclay, CNRS, Institut d’astrophysique spatiale, 91405 Orsay, France
⁴ Laboratoire Univers et Particules de Montpellier, Université de Montpellier, CNRS/IN2P3, CC 72, Place Eugène Bataillon, 34095 Montpellier Cedex 5, France
⁵ AIM, CEA, CNRS, Université Paris-Saclay, Université Paris Diderot, Sorbonne Paris Cité, 91191 Gif-sur-Yvette, France

Received: 29 October 2021
Accepted: 18 February 2022

Abstract

Thermal ionization is a critical process at temperatures T > 10³ K, particularly during star formation. An increase in ionization leads to a decrease in nonideal magnetohydrodynamics (MHD) resistivities, which has a significant impact on protoplanetary disks and protostar formation. We developed an extension of the fast computational ionization method presented in our recent paper to include thermal ionization. The model can be used to inexpensively calculate the density of ions and electrons and the electric charge of each size of grains for an arbitrary size distribution. This tool should be particularly useful for the self-consistent calculation of nonideal MHD resistivities in multidimensional simulations, especially of protostellar collapse and protoplanetary disks.