Calcium II infrared triplet line models in classical T Tauri stars

¹ Centro de Astrofísica da Universidade do Porto (CAUP), Rua das Estrelas, 4150-762 Porto, Portugal e-mail: razevedo@astro.up.pt
² Harvard-Smithsonian Center for Astrophysics, 60 Cambridge, MA 02138, USA
³ Departamento de Matemática Aplicada da Faculdade de Ciências da Universidade do Porto, Rua do Campo Alegre 687, 4169-007 Porto, Portugal
⁴ Instituto Superior de Ciências da Saúde – Norte, Rua Central da Gandra 1317, 4585-116 Gandra PRD, Portugal
⁵ Steward Observatory, University of Arizona, 933 North Cherry Avenue, Tucson, AZ 85721, USA

Received: 7 October 2005
Accepted: 7 June 2006

Abstract

We study the formation of the calcium II infrared triplet lines 8498 Å, 8542 Å and 8662 Å, in the accreting magnetospheric flows of Classical T Tauri stars (CTTS), and present a grid of models for a large range of magnetospheric conditions. We apply our models to the interpretation of multi epoch observations of the CTTS DI Cep. We find that these lines form in the magnetospheric infall and that the variability of the CaII triplet lines in DI Cep can be explained in the context of changes in the mass accretion rate/temperature of the accretion column gas.