Spectral study of MWC 560 . Parameters of the system , the hot source and the jets

Results of spectroscopy of unusual symbiotic variable star MWC560 are presented. The data have been obtained from autumn 1990 to spring 1993. High velocity absorption lines of H I, D1 D2 Na I, Fe II(42) and He I are permanently presented in the spectra, their radial velocity is −500 ÷ −2500 km/s and is changed with a time–scale of a few months. The high velocity absorption line profiles demonstrate their origin in a jet, directed closely to the line of sight. These absorptions are variable at a time-scale less than one day and with an amplitude of about 10 %. The fast variability of the absorption line profiles at <∼ 3 hours have been observed. An evidence of the opposite (second) jet has been found — there is an additional and variable emission in a red wing of the Hα emission line profile. The radial velocity of this emission corresponds to the jet velocity, measured from the absorption lines. An estimates of the orbital inclination angle (i ≈ 10) and the jets parameters have been derived. We have simulated the continuum spectrum from UV to IR in the two different states (high and low) of MWC560. The observed spectrum is formed in a M4–5III giant, a hot source and in an absorbing screen (the jet). The interstellar absorption is AV = 1 . 4÷ 1. 6. The jet opening angle 2 θj >∼ 40 , the jet length in the place of the absorption is ≈ 1 · 10 cm. The absorbing gas temperature and density are Tj ≈ 8000 K and n ≈ 5 · 10 11 cm. The jet column density is variable and equal to N ≈ 3÷ 6 · 10 cm. At different states of the object only the jet velocity is changed (and, accordingly, N), but the mass loss rate in the jet is about constant and equal to Ṁj ≈ 5 · 10 −7 M⊙/y. The object luminousity Lbol ≈ 2 · 10 37 erg/s is radiated mainly by the UV source, whose temperature and size are T ≈ 20000 K and R ≈ 4 · 10 cm. The hot source is probably a photosphere of a massive wind (Ṁj ≈ 2 · 10 −6 M⊙/y, V = 100÷ 200 km/s) rising from inner area aroung the white dwarf. We suppose that both the wind and jets are accelerated in magnetic field of the white dwarf, which accretes the gas from the giant wind as a propeller. The gas flows in accretion disk and is expelled from that by the rotating magnetic field. A sectorial structure of the outflow (jets) is formed. The different states of MWC560 could be corresponding to different propeller regimes: a hard propeller with a gas velocity outflow a few thousands of km/s and a soft propeller with a few hundred km/s. A total mass accretion rate onto the propeller is Ṁ ≈ 3÷ 4 · 10 M⊙/y. A main part of this mass flux (about 50 – 70 %) is outflowed as a slow wind, <∼ 15 % could reach the white dwarf surface and about 20 – 30 % is expelled as a jets. A surface magnetic field strength on the white dwarf is 3 · 10 G <∼ BS <∼ 3 · 10 9 G, its rotational period is from 10 – 20 minutes to 3 hours.