Astronomy and Astrophysics – Astrophysics
Scientific paper
Aug 1994
adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=1994apj...431..264i&link_type=abstract
The Astrophysical Journal, Part 1, vol. 431, no. 1, p. 264-272
Astronomy and Astrophysics
Astrophysics
39
Cataclysmic Variables, Stellar Evolution, Stellar Interiors, Stellar Mass Accretion, Supernovae, White Dwarf Stars, X Ray Sources, Binary Stars, Companion Stars, Degenerate Matter, Helium, Stellar Envelopes
Scientific paper
Binaries with initial component masses in the range 7-10 stellar mass can evolve into systems consisting of a massive degenerate dwarf which is accreting pure helium at the rate of approximately 10-6 to 10-5 stellar mass/yr from a massive companion, whose precursor first fills its Roche lobe as a giant with a deep convective envelope. The mass-exchange rate in these 'helium Algols' is precisely in the interval which allows the degenerate dwarf to burn the accreted helium in a quasi-stationary way. Thus, some massive dwarfs have a realistic possibility of reaching the Chandrasekhar limit and exploding as a supernova. In our Galaxy, the frequency of such supernovae may be approximately 1.7 x 10-3/yr. During the phase of quasi-stationary helium shell burning, helium-accreting dwarfs are very bright (L approximately = 1037 - 1038 erg/s, stationary or flaring ultrasoft X-ray sources like those discovered recently in galaxies of the Local Group. Cataclysmic variable-like (CV-like) systems in which hydrogen-rich matter is transferred on the thermal timescale of the envolope of an envolved main-sequence donor can also contribute to the population of ultra-soft X-ray sources. We discuss the properties of such systems and conclude that futher observational studies are needed to determine the relative contribution of helium Algols and of CV-like systems to the family of ultrasoft X-ray binaries.
Iben Icko Jr.
Tutukov Aleksandr V.
No associations
LandOfFree
Helium-accreting degenerate dwarfs as presupernovae and scenarios for the ultrasoft x-ray sources does not yet have a rating. At this time, there are no reviews or comments for this scientific paper.
If you have personal experience with Helium-accreting degenerate dwarfs as presupernovae and scenarios for the ultrasoft x-ray sources, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Helium-accreting degenerate dwarfs as presupernovae and scenarios for the ultrasoft x-ray sources will most certainly appreciate the feedback.
Profile ID: LFWR-SCP-O-1494426