Three-dimensional simulations of the interaction between the nova ejecta, accretion disk, and companion star^★

¹ Departament de Física, EEBE, Universitat Politècnica de Catalunya, c/ Eduard Maristany 10, 08930 Barcelona, Spain
e-mail: jordi.jose@upc.edu
² Institut d’Estudis Espacials de Catalunya, c/ Gran Capità 2-4, Ed. Nexus-201, 08034 Barcelona, Spain
³ Departament de Física, Universitat Politècnica de Catalunya, c/ Esteve Terrades 5, 08860 Castelldefels, Spain
⁴ Max-Planck-Institut für Astrophysik, Karl-Schwarzschild-Strasse 1, 85748 Garching bei München, Germany
⁵ School of Physics and Astronomy, Monash University, Clayton 3800, Victoria, Australia
⁶ Monash Centre for Astrophysics (MoCA), Monash University, Clayton 3800, Victoria, Australia
⁷ South African Astronomical Observatory, PO Box 9, Observatory Rd., 7935 Cape Town, South Africa
⁸ Astronomy Department, University of Cape Town, 7701 Rodenbosch, South Africa
⁹ South Africa National Institute for Theoretical Physics, Private Bag X1, Matieland, 7602 Stellenbosch, South Africa

Received: 11 July 2017
Accepted: 20 December 2017

Abstract

Context. Classical novae are thermonuclear explosions hosted by accreting white dwarfs in stellar binary systems. Material piles up on top of the white dwarf star under mildly degenerate conditions, driving a thermonuclear runaway. The energy released by the suite of nuclear processes operating at the envelope, mostly proton-capture reactions and β⁺-decays, heats the material up to peak temperatures ranging from 100 to 400 MK. In these events, about 10⁻³–10⁻⁷ M_⊙, enriched in CNO and, sometimes, other intermediate-mass elements (e.g., Ne, Na, Mg, and Al) are ejected into the interstellar medium.

Aims. To date, most of the efforts undertaken in the modeling of classical nova outbursts have focused on the early stages of the explosion and ejection, ignoring the interaction of the ejecta, first with the accretion disk orbiting the white dwarf and ultimately with the secondary star.

Methods. A suite of 3D, smoothed-particle hydrodynamics (SPH) simulations of the interaction between the nova ejecta, accretion disk, and stellar companion were performed to fill this gap; these simulations were aimed at testing the influence of the model parameters—that is, the mass and velocity of the ejecta, mass and the geometry of the accretion disk—on the dynamical and chemical properties of the system.

Results. We discuss the conditions that lead to the disruption of the accretion disk and to mass loss from the binary system. In addition, we discuss the likelihood of chemical contamination of the stellar secondary induced by the impact with the nova ejecta and its potential effect on the next nova cycle.