High-Dispersion Spectroscopy of the Symbiotic Star Ax-Persei - a Binary Model with Rapid Mass Accretion

Results of high-dispersion spectroscopy (∼10 Å mm^‑1) of the symbiotic star AX Per carried out in the years from 1979 to 1987 are reported. The emission line [FeVII] 6086 consists of a narrow and a broad component; the radial velocity of the narrow one varies according to the photometric period 681.6 days. This variation (K=30.6±1.5 km s^‑1) seems to be due to the orbital motion of the hot star. The radial velocity of absorption lines varies with an inverse phase dependence and a much smaller amplitude (K=5.6±2 km s^‑1), which may reflect the orbital motion of the red giant. The variation of the radial velocity of the emission lines of FeII, ect. (K=6.7±1.5 km s^‑1) might be due to the rotation of the red giant. The profile of Hα emission line suddenly changed around the phase of the photometric minimum, which could be explained as a result of an eclipse of the emitting region by the red giant. On the other hand, some problems remain open in the behaviour of the radial velocities of Hα and HeI 5876. The observed results support a binary model of AX Per consisting of a rather massive (∼3M_⊙) M-type giant and a Main-Sequence star (∼0.6M_⊙). AX Per seems to be in an early stage of the Case C mass transfer, and the estimated very high mass accretion rate (∼10^‑4M_⊙ yr^‑1) is consistent with the theoretical models. The narrow component of the emission line of [FeVII] 6086 might be emitted in radiatively driven polar jets on the hot star of which luminosity is close to the Eddington limit. A new identification as ZrII at 6106.47 Å is proposed for the emission line at 6106 Å.