Astronomers are trying to determine the answer to the question of whether there is a direct relationship between Type Ia Supernovae (SNeIa), Classical Novae (CNe) and Recurrent Novae (RNe). Some evidence has been found to support a distinct relationship between catastrophic SNe events and RNe outbursts. There is evidence that a tipping of the scale into a full-fledged Type Ia SN may be related to RNe, and though some evidence seems to point to this, all the particulars are not out regarding the three types. Do the three events occur within the same stellar mass, or are they separate events occurring in separate stellar masses.
|Las Cumbres Observatory Global Telescope Network|
Symbiotic binaries are systems containing both a white dwarf (WD) and a red giant component. Symbiotic novae are those systems in which thermonuclear eruptions occur on the WD component. These are to be distinguished from events are driven by accretion disk instabilities analogous to dwarf novae eruptions in cataclysmic variable outbursts. Another class of symbiotic system is that 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 Type Ia SN if it can hide the hydrogen and helium in the system)? In order to better understand these systems, a new study has begun 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. Astrophysicists have put into use a 1-D hydrocode, NOVA, which includes the new convective algorithm of Arnett, Meakin, and Young, the Hix and Thielemann nuclear reaction solver, the Iliadis reaction rate library, the Timmes equation of state, and the OPAL opacities. It is reported that (1) the WD grows in mass for all simulations so that canonical 'steady burning' does not occur, and, (2) that only a small fraction of the accreted matter is ejected in some (but not all) simulations. They have also found that the accreting systems, before thermonuclear runaway, are too cool to be seen in X-ray searches for Type Ia SN progenitors.
|SN PTF 11kx Imaged by BJ Fulton |
Las Cumbres Global Telescope Network
This research has made use of the NASA/IPAC Extragalactic Database (NED) which is operated by the Jet Propulsion Laboratory, California Institute of Technology, under contract with the National Aeronautics and Space Administration; The Palomar Transient Factory at the California Institute of Technology; Baltic Astronomy, Vol 21, pages 76 - 87, 201arXiv:1211.6145v1 [astro-ph.SR]