IM Normae: The Death Spiral of a Cataclysmic Variable?

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 1...

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Published in:arXiv.org 2021-03
Main Authors: Patterson, Joseph, Kemp, Jonathan, Berto Monard, Myers, Gordon, de Miguel, Enrique, Franz-Josef Hambsch, Warhurst, Paul, Rea, Robert, Dvorak, Shawn, Menzies, Kenneth, Vanmunster, Tonny, Roberts, George, Campbell, Tut, Starkey, Donn, Ulowetz, Joseph, Rock, John, Seargeant, Jim, Boardman, James, Lemay, Damien, Cejudo, David, Knigge, Christian
Format: Article
Language:English
Subjects:
Binary stars
Cataclysmic variables
Deposition
Dwarf novae
Light curve
Luminosity
Mass transfer
Occultation
Orbits
Outbursts
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Summary: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.
ISSN:2331-8422