We have continued our studies of the evolution of Thermonuclear Runaways (TNR) in the accreted envelopes of massive white dwarfs (WD) and here we focus on the 2006 outburst of the Recurrent Symbiotic Nova (RN) RS Oph. RS Oph is a member of a small class of close binary systems in which the orbital period is long ( 460 d), the secondary is an M giant, and the WD is thought to be close in mass to the Chandrasekhar Limit. RS Oph explodes about every 20 years and the ejected material from the WD runs into the expanding outer layers of the M giant causing a wonderful display of "fireworks” that emit from gamma-rays to the radio. One important question is the secular evolution of the WD. Do the repeated outbursts cause the WD to gain or lose mass? If it is gaining mass, it could eventually reach the Chandrasekhar Limit and become a supernova or even a SN Ia if it can hide the hydrogen and helium in the system. We will report on our latest studies of TNRs using a variety of initial WD luminosities and mass accretion rates onto the WD (1.35 and 1.38 solar masses). We use our 1-D hydro code, NOVA, that now includes the Hix and Thielemann nuclear reaction network, the latest Iliadis reaction rate library, the Timmes equation of state, and OPAL opacities. We will report on the amount of ejected mass, ejection velocities, evolution time to explode, and the chemical composition of the ejecta.We gratefully acknowledge partial support from the DOE, NASA, and NSF for these studies.
American Astronomical Society Meeting Abstracts #214
- Pub Date:
- May 2009