Identification and Spectroscopic Characterization of 128 New Herbig Stars* *Based on observations collected at the European Southern Observatory (ESO) under ESO program 0104.C-0937(A) and 0104.C-0937(B), observations made in the Observatorios de Canarias del IAC, program 103-INT13/19B, and observations collected at the Centro Astronómico Hispano-Alemán (CAHA) at Calar Alto from 2019-04-Sept to 2019-06-Sept.

Abstract

We present optical spectroscopy observations of 145 high-mass pre-main-sequence candidates from the catalog of Vioque et al. 2020 From these, we provide evidence for the Herbig nature of 128 sources. This increases the number of known objects of the class by ∼50%. We determine the stellar parameters of these sources using the spectra and Gaia EDR3 data. The new sources are well distributed in mass and age, with 23 sources between 4 and 8 M ⊙ and 32 sources above 8 M ⊙. Accretion rates are inferred from Hα and Hβ luminosities for 104 of the new Herbigs. These accretion rates, combined with previous similar estimates, allow us to analyze the accretion properties of Herbig stars using the largest sample ever considered. We provide further support to the existence of a break in accretion properties at ∼3–4 M ⊙, which was already reported for the previously known Herbig stars. We re-estimate the potential break in accretion properties to be at M ⊙. As observed for the previously known Herbig stars, the sample of new Herbig stars independently suggests intense inner-disk photoevaporation for sources with masses above ∼7 M ⊙. These observations provide robust observational support to the accuracy of the Vioque et al. 2020 catalog of Herbig candidates.