SIMBAD references

A scenario for a periodic filling and emptying of the accretion disc of the microquasar GRS 1915+105 is proposed, by estimating the mass transfer rate from the donor and comparing it with the observed accretion rate onto the primary black hole. The mass of the Roche-lobe-filling donor (1.2±0.2M_☉), the primary black hole mass (14±4M_☉) and the binary orbital period of 33.5d (Greiner et al., 2001Natur.414..522G) predict for the donor spectral type and K-magnitude around K6 III and -2.6, respectively. The He-core of 0.28M_☉ of such a giant leads to evolutionary expansion along the giant branch with a conservative mass transfer rate of {dot}(M)_d=(1.5±0.5)x10^–8M_☉/year. On the other hand, the average observed accretion rate onto the primary is ten times larger: {dot}(M)_obs=2.0x(η/0.1)^–1(d/12.5 kpc)²x10^–7M_☉/y, where η is the efficiency of converting accretion into radiation. We propose a duty cycle with (5-10)(η/0.1) per cent active ON-state. The timescale of the (recurrent) OFF-state is identified as the viscosity time scale at the circularization radius (14R_☉) and equals t_visc=370(α/0.001)^–4/5 years, where α is the viscosity parameter in the α-prescription of a classical disc. If the viscosity at the outer edge of the disc is small and η is close to the maximum available potential energy (per rest mass energy) at the innermost stable orbit, the present activity phase may still last another 10-20 years. We also discuss other solutions allowing a broader range of donor masses (0.6-2.4M_☉).