A study of many-year spectral variability of the Ae Herbig star HD 36112

Abstract

We present the results of long-term high-dispersion spectral observations (R = 20000) of the Ae Herbig star HD 36112 in the regions of the Ha emission line and the NaI D resonance doublet lines. They show that parameters of the Ha emission line demonstrate complicated variability on several time scales: 1) variability from night to night caused by inhomogeneity of the circumstellar envelope; 2) variability on a time scale of about 1200d characterized by a variation of the equivalent width, intensity, and other emission parameters; 3) variability on a time scale of more than 4000d observed as a many-year trend in variations of parameters of the Ha emission line.
 We associate these results with variability of physical and kinematic conditions in the inner regions of the accretion disk and wind. The most probable mechanism of this variability is a process of planet formation in the circumstellar disk.