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| Paper: |
Helium Shell Flash Object V445 Puppis and Mass Loss During Helium Novae |
| Volume: |
330, The Astrophysics of Cataclysmic Variables and Related Objects |
| Page: |
311 |
| Authors: |
Kato, M. |
| Abstract: |
The 2001 outburst of V445 Puppis shows unique properties, such as absence of hydrogen, enrichment of helium and carbon, slow light curve with a small amplitude that does not resemble to any type of novae. This object is suggested to be the first example of helium nova, and I have calculated theoretical light curves of helium novae and reproduce the observational light curve of V445 Pup. Fitting indicates a very massive white dwarf (> 1.3MSolar), with estimated ignition mass 5 × 10−5MSolar, which correspond to the helium accretion rate of 7 × 10−7MSolar yr−1 and the recurrence period of 70 years (for M = 1.33MSolar). These values suggests that the white dwarf (WD) is growing in mass and ends up either a Type Ia supernova or an accretion induced collapse to form a neutron star. I have also calculated the mass accumulation efficiency during helium shell flashes for various white dwarf masses and the helium accretion rates. This efficiency is a crucial factor for binary evolutions to Type Ia supernovae. The ef- ficiency takes the minimum values in between 1.1 and 1.2 MSolar WD and increases in both less and more massive WDs. The mass accumulation efficiency is larger than 0.5 for log dM/dt(He) > −6.72 in all the WD masses. |
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