Spectroscopic study of Herbig Ae/Be stars in the Galactic anti-centre region from LAMOST DR5

We study a sample of 119 Herbig Ae/Be stars in the Galactic anti-centre direction using the spectroscopic data from large sky area multi-object fiber spectroscopic telescope survey program. Emission lines of hydrogen belonging to the Balmer and Paschen series, and metallic lines of species such as FeII, OI, CaII triplet are identified. A moderate correlation is observed between the emission strengths of H alpha and Fe II 5169 angstrom, suggesting a possible common emission region for FeII lines and one of the components of Ha. We explored a technique for the extinction correction of the HAeBe stars using diffuse interstellar bands present in the spectrum. We estimated the stellar parameters such as age and mass of these HAeBe stars, which are found to be in the range 0.1-10 Myr and 1.5-10 M-circle dot, respectively. We found that the mass accretion rate of the HAeBe stars in the Galactic anti-centre direction follows the relation M-acc proportional to M3.12+0. 21-0.34 , which is similar to the relation derived for HAeBe stars in other regions of the Galaxy. The mass accretion rate of HAeBe stars is found to have a functional form of M-acc(.) proportional to t (-1.1 +/- 0.2) with age, in agreement with previous studies.

Automated summary

In this study, we examined a sample of 119 Herbig Ae/Be stars in the Galactic anti-centre direction using spectroscopic data from the large sky area multi-object fiber spectroscopic telescope survey program. We identified emission lines of hydrogen and metallic lines of FeII, OI, CaII triplet. We also explored a technique for the extinction correction of these stars and estimated their stellar parameters and mass accretion rates.