The spin of central black holes with intermediate masses in globular clusters is determined using the well known relationship between the kinetic power of a relativistic jet and the observed radio luminosity of the region closest to a central black hole. The estimate of the magnitude of the spin is based on the knownBlandford-Znajek mechanism. The magnetic field near the event horizon of a black hole is determined using a magnetic coupling mechanism that assumes equality between the densities of the magnetic and kinetic energies of the accreting gas (the Magnetic Coupling Model). The rate of accretion M is derived on the basis of the Bondi-Hoyle mechanism.

Results from an analysis of a forty year series of photographic observations of the binary star 61 Cyg on the 26 inch refractor at the Pulkovo Observatory are presented. The orbit is constructed and the sum of the masses of the components is determined from the relative positions of the components. A study of the individual motions of the components of 61 Cyg relative to the surrounding stars yields their mass ratio and the masses of the main and secondary components, 0.74 and 0.46 solar masses, respectively. The relative motion of the components is found to have a fluctuating component with a period of 6.5 years which may be caused, in particular, by the presence in the system of a dark, low-mass companion.

No abstract

No abstract

No abstract