The evolutionary status of Cataclysmic Variables: eclipse modelling of 15 systems

McAllister, M.; Littlefair, S. P.; Parsons, S. G.; Dhillon, V. S.; Marsh, T. R.; Gänsicke, B. T.; Breedt, E.; Copperwheat, C.; Green, M. J.; Knigge, C.; Sahman, D. I.; Dyer, Martin J.; Kerry, P.; Ashley, R. P.; Irawati, P.; Rattanasoon, S.
Bibliographical reference

Monthly Notices of the Royal Astronomical Society, Volume 486, Issue 4, p.5535-5551

Advertised on:
7
2019
Number of authors
16
IAC number of authors
1
Citations
55
Refereed citations
44
Description
We present measurements of the component masses in 15 Cataclysmic Variables (CVs) - 6 new estimates and 9 improved estimates. We provide new calibrations of the relationship between superhump period excess and mass ratio, and use this relation to estimate donor star masses for 225 superhumping CVs. With an increased sample of donor masses we revisit the implications for CV evolution. We confirm the high mass of white dwarfs in CVs, but find no trend in white dwarf mass with orbital period. We argue for a revision in the location of the orbital period minimum of CVs to 79.6 ± 0.2 min, significantly shorter than previous estimates. We find that CV donors below the gap have an intrinsic scatter of only 0.005 R⊙ around a common evolutionary track, implying a correspondingly small variation in angular momentum loss (AML) rates. In contrast to prior studies, we find that standard CV evolutionary tracks - without additional AML - are a reasonable fit to the donor masses just below the period gap, but that they do not reproduce the observed period minimum, or fit the donor radii below 0.1 M⊙.
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