IRAS03063+5735: A Bowshock Nebula Powered by an Early B Star

TL;DR

This study identifies IRAS 03063+5735 as a bowshock nebula created by an early B star, providing insights into its properties, distance, and possible origin, and introduces spectral diagnostic tools for classifying O and B stars.

Contribution

The paper presents the classification of the star as B1.5 V, estimates its distance, and links it to a molecular cloud, also introducing spectral diagnostic diagrams for O and B stars.

Findings

The star is a B1.5 V type at ~4 kpc distance.

The nebula is likely caused by a high-velocity runaway star.

Spectral diagnostic diagrams for O and B stars are developed.

Abstract

Mid-infrared images from the Spitzer Space Telescope Galactic Legacy Infrared MidPlane Survey Extraordinaire program reveal that the infrared source IRAS 03063+5735 is a bowshock nebula produced by an early B star, 2MASS 03101044+5747035. We present new optical spectra of this star, classify it as a B1.5 V, and determine a probable association with a molecular cloud complex at V_LSR=-38 -- -42 km/s in the outer Galaxy near l=140.59 degr, b=-0.250 degr. On the basis of spectroscopic parallax, we estimate a distance of 4.0 +/-1 kpc to both the bowshock nebula and the molecular complex. One plausible scenario is that this a high-velocity runaway star impinging upon a molecular cloud. We identify the HII region and stellar cluster associated with IRAS 03064+5638 at a projected distance of 64 pc as one plausible birth site. The spectrophotometric distance and linkage to a molecular feature provides another piece of data helping to secure the ill-determined rotation curve in the outer Galaxy. As a by-product of spectral typing this star, we present empirical spectral diagnostic diagrams suitable for approximate spectral classification of O and B stars using He lines in the little-used yellow-red portion of the optical spectrum.