Unlocking Galactic Wolf-Rayet stars with $\text{Gaia}$ DR2 I: Distances and absolute magnitudes

Abstract

We obtain distances to 383 Galactic Wolf-Rayet (WR) stars from $\text{Gaia}$ DR2 parallaxes and Bayesian methods, with a prior based on H$\mathrm{II}$ regions and dust extinction. Distances agree with those from Bailer-Jones et al. for stars up to 2 kpc from the Sun, though deviate thereafter due to differing priors, leading to modest reductions in luminosities for recent WR spectroscopic results. We calculate visual and K-band absolute magnitudes, accounting for dust extinction contributions and binarity, and identify 187 stars with reliable absolute magnitudes. For WR and O stars within 2 kpc, we find a WR/O ratio of 0.09. The distances are used to generate absolute magnitude calibrations and obtain the $\text{Gaia}$ colour magnitude diagram for WR stars. Average $v^{\mathrm{WR}}$-band absolute magnitudes for WN stars range from -3.6 mag (WN3-4) to -7.0 mag (WN8-9ha), and -3.1 (WO2-4) to -4.6 mag (WC9), with standard deviations of $\sim$0.6 mag. Using H$\mathrm{II}$ region scale heights, we identify 31 WR stars at large (3$\sigma$, |z|$\ge$156 pc) distances from the mid-plane as potential runaways accounting for the Galactic warp, of which only 4 involve WN8-9 stars, contrary to previous claims.

Amended section 3.3, table 4, table 5 and table 6 based on corrected Av to AK conversion. Minor updates to figures, WR/O ratio and WR stars with reliable results. 19 pages, 15 figures. Additional appendices updated (57 pages, 5 figures). To be published in MNRAS

References in corpus (23)

• The NumPy array: a structure for efficient numerical computation
• The Gaia mission
• Binary interaction dominates the evolution of massive stars
• Physical Properties of Wolf-Rayet Stars
• The High Angular Resolution Multiplicity of Massive Stars
• Gaia Data Release 1: Catalogue validation
• The Galactic WN stars: Spectral analyses with line-blanketed model atmospheres versus stellar evolution models with and without rotation
• UBVJHK synthetic photometry of Galactic O stars
• The VST Photometric Halpha Survey of the Southern Galactic Plane and Bulge (VPHAS+)
• A census of the Wolf-Rayet content in Westerlund 1 from near-infrared imaging and spectroscopy
• The Galactic WC stars: Stellar parameters from spectral analyses indicate a new evolutionary sequence
• A multi-wavelength view on the dusty Wolf-Rayet star WR 48a
• The Second Data Release of the INT Photometric H-Alpha Survey of the Northern Galactic Plane (IPHAS DR2)
• The different progenitors of type Ib, Ic SNe, and of GRB
• Distances and parallax bias in Gaia DR2
• Spatial distribution of Galactic Wolf-Rayet stars and implications for the global population
• The Galactic WN stars revisited. Impact of Gaia distances on fundamental stellar parameters
• A Spectroscopic Survey of WNL Stars in the LMC: General Properties and Binary Status
• The Massive Star Content of NGC 3603
• Searching for hidden Wolf-Rayet stars in the Galactic Plane - 15 new Wolf-Rayet stars
• Do Wolf-Rayet stars have similar locations in hosts as type Ib/c supernovae and long gamma-ray bursts?
• The ESA Gaia Archive: Data Release 1
• Investigating the origin of the spectral line profiles of the Hot Wolf-Rayet Star WR2

Cited by in corpus (11)

• Runaway and walkaway stars from the ONC with Gaia DR2
• Revisiting the Impact of Dust Production from Carbon-Rich Wolf-Rayet Binaries
• Unlocking Galactic Wolf-Rayet stars with $\text{Gaia}$ DR2 II: Cluster and Association membership
• Two Wolf-Rayet stars at the heart of colliding-wind binary Apep
• On the ring nebulae around runaway Wolf-Rayet stars
• The nature of the companion in the Wolf-Rayet system EZ Canis Majoris
• Dust in the Wolf-Rayet Nebula M1-67
• Megahertz emission of massive early-type stars in the Cygnus region
• An extensive spectroscopic time series of three Wolf-Rayet stars -- II. A search for wind asymmetries in the dust-forming WC7 binary WR137
• A global view on the colliding-wind binary WR 147
• The K supergiant runaway star HD 137071