Hydrodynamic Studies of the Evolution of Recurrent, Symbiotic and Dwarf Novae: the White Dwarf Components are Growing in Mass

Abstract

Symbiotic binaries are systems with white dwarfs (WDs) and red giant companions. Symbiotic novae are those systems in which thermonuclear eruptions occur on the WD components. These are to be distinguished from events driven by accretion disk instabilities analogous to Dwarf Novae eruptions in Cataclysmic Variable outbursts. Another class of Symbiotic systems are those in which the WD is extremely luminous and it seems likely that quiescent nuclear burning is ongoing on the accreting WD. A fundamental question is the secular evolution of the WD. Do the repeated outbursts or quiescent burning in these accreting systems cause the WD to gain or lose mass? If it is gaining mass, can it eventually reach the Chandrasekhar Limit and become a supernova (a SN Ia if it can hide the hydrogen and helium in the system)? In order to better understand these systems, we have begun a new study of the evolution of Thermonuclear Runaways (TNRs) in the accreted envelopes of WDs using a variety of initial WD masses, luminosities, and mass accretion rates. We use our 1-D hydro code, NOVA, which includes the new convective algorithm of Arnett, Meakin, and Young, the Hix and Thielemann nuclear reaction solver, the lliadis reaction rate library, the Timmes equation of state, and the OPAL opacities. We assume a solar composition (Lodders abundance distribution) and do not allow any mixing of accreted material with core material. This assumption strongly influences our results.We report here (1) that the WD grows in mass for all simulations so that "steady burning" does not occur, and (2) that only a small fraction of the accreted matter is ejected in some (but not all) simulations. We also find that the accreting systems, before thermonuclear runaway, are too cool to be seen in X-ray searches for SN Ia progenitors.

The 2011 Outburst of Recurrent Nova T Pyx: Radio Observations Reveal the Ejecta Mass and Hint at Complex Mass Loss

“…The quiescence observations of T Pyx are inconsistent with either of these pictures Selvelli et al (2008). More recent studies have found that nova outbursts can happen on white dwarfs accreting at much higher rates than previous studies (Starrfield et al 2012;Idan et al 2013). T Pyx may be an example of such a system, although the high ejected mass is not found for most outbursts in these models.…”

Observational signatures of SNIa progenitors, as predicted by models

“…Our detailed evolutionary calculations, as well as those of Starrfield et al (2012) and Idan et al (2013) demonstrate that a state of steady hydrogen burning does not occur. Cal 83 was observed with alternating optical/X-ray states as well, repeating every ∼ 450 days, spending about ∼ 250 days in the high state and ∼ 200 days in the low state (Rajoelimanana et al, 2013, fig.1).…”

Chemical and Physical Parameters From X-Ray High-Resolution Spectra of the Galactic Nova V959 Mon

“…Each outburst ejects mass into the interstellar medium (ISM), from a few 10 −7 M to a few 10 −4 M , depending on the mass accretion rate and time necessary for the pressure at the bottom of the accreted layer to exceed the gravitational pressure. This pressure is mostly an inverse function of the WD mass (Starrfield et al 2012;Wolf et al 2013).…”