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

TL;DR

This study analyzes 119 Herbig Ae/Be stars in the Galactic anti-center using LAMOST spectroscopic data, identifying emission lines, estimating stellar parameters, and examining accretion rates, revealing consistency with known relations across the Galaxy.

Contribution

First detailed spectroscopic analysis of Herbig Ae/Be stars in the Galactic anti-center region using LAMOST data, including emission line identification and accretion rate estimation.

Findings

Emission lines of hydrogen and metals identified

Mass accretion rate correlates with stellar mass as $ ightarrow M_*^{3.12}$

Mass accretion rate decreases with age as $ ightarrow t^{-1.1}$

Abstract

We study a sample of 119 Herbig Ae/Be stars in the Galactic anti-center direction using the spectroscopic data from Large sky Area Multi-Object fiber Spectroscopic Telescope (LAMOST) 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 FeII 5169 \r{A}, suggesting a possible common emission region for FeII lines and one of the components of H$\alpha$. 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 $M_{\odot}$, respectively. We found that the mass accretion rate of the HAeBe stars in the Galactic anti-center direction follows the relation $\dot{M}_{acc}$ $\propto$ $M_{*}^{3.12^{+0.21}_{-0.34}}$, 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 $\dot{M}_{acc} \propto t^{-1.1 \pm 0.2}$ with age, in agreement with previous studies.