IM Normae: The Death Spiral of a Cataclysmic Variable?

Joseph Patterson; Jonathan Kemp; Berto Monard; Gordon Myers; Enrique de Miguel; Franz-Josef Hambsch; Paul Warhurst; Robert Rea; Shawn Dvorak; Kenneth Menzies; Tonny Vanmunster; George Roberts; Tut Campbell; Donn Starkey; Joseph Ulowetz; John Rock; Jim Seargeant; James Boardman; Damien Lemay; David Cejudo; Christian Knigge

arXiv · 2010.07812

IM Normae: The Death Spiral of a Cataclysmic Variable?

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Abstract

We present a study of the orbital light curves of the recurrent nova IM Normae since its 2002 outburst. The broad "eclipses" recur with a 2.46 hour period, which increases on a timescale of 1.28(16)x10^6 years. Under the assumption of conservative mass-transfer, this suggests a rate near 10^-7 M_sol/year, and this agrees with the estimated /accretion/ rate of the postnova, based on our estimate of luminosity. IM Nor appears to be a close match to the famous recurrent nova T Pyxidis. Both stars appear to have very high accretion rates, sufficient to drive the recurrent-nova events. Both have quiescent light curves which suggest strong heating of the low-mass secondary, and very wide orbital minima which suggest obscuration of a large "corona" around the primary. And both have very rapid orbital period increases, as expected from a short-period binary with high mass transfer from the low-mass component. These two stars may represent a final stage of nova -- and cataclysmic-variable -- evolution, in which irradiation-driven winds drive a high rate of mass transfer, thereby evaporating the donor star in a paroxysm of nova outbursts.

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Joseph Patterson, Jonathan Kemp, Berto Monard, Gordon Myers, Enrique de Miguel, Franz-Josef Hambsch, Paul Warhurst, Robert Rea, Shawn Dvorak, Kenneth Menzies, Tonny Vanmunster, George Roberts, Tut Campbell, Donn Starkey, Joseph Ulowetz, John Rock, Jim Seargeant, James Boardman, Damien Lemay, David Cejudo, Christian Knigge. 2020-10-15. IM Normae: The Death Spiral of a Cataclysmic Variable?. https://arxiv.org/abs/2010.07812

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