The Galactic O-Star Spectroscopic Survey (GOSSS). III. 142 additional O-type systems

TL;DR

This paper reports the addition of 142 new O-star systems to the Galactic O-Star Spectroscopic Survey, including new binaries, classifications, and revisions, significantly expanding the catalog of known Galactic O stars.

Contribution

It provides the largest homogeneous spectroscopic dataset of Galactic O stars to date, including new classifications, binary identifications, and methodological updates.

Findings

Added 142 new O-star systems to GOSSS

Identified 11 new double-lined and 1 triple-lined spectroscopic binaries

Revised classifications and introduced luminosity class IV for certain spectral types

Abstract

This is the third installment of GOSSS, a massive spectroscopic survey of Galactic O stars, based on new homogeneous, high signal-to-noise ratio, R~2500 digital observations selected from the Galactic O-Star Catalog (GOSC). In this paper we present 142 additional stellar systems with O stars from both hemispheres, bringing the total of O-type systems published within the project to 590. Among the new objects there are 20 new O stars. We also identify 11 new double-lined spectroscopic binaries (SB2s), of which 6 are of O+O type and 5 of O+B type, and an additional new tripled-lined spectroscopic binary (SB3) of O+O+B type. We also revise some of the previous GOSSS classifications, present some egregious examples of stars erroneously classified as O-type in the past, introduce the use of luminosity class IV at spectral types O4-O5.5, and adapt the classification scheme to the work of Arias et al. (2016).