Detection of new Galactic Wolf-Rayet stars with SPHEREx

Abstract

We assess the potential for the NASA Explorer SPHEREx mission in adding to the Milky Way census of Wolf-Rayet (WR) stars by extracting 0.75–5μm spectrophotometry of 30 candidate WR stars previously identified using Gaia XP spectra. We confirm an additional Galactic 13 WR (8 WN and 5 WC) stars, identify 3 probable [WC]-type central stars of Planetary Nebulae, plus 2 He emission line sources. SPHEREx has the potential to detect additional relatively isolated WR stars on the far size of the Milky Way by combining Machine Learning techniques with a judicious choice of candidate selection criteria. Indeed SPHEREx is sufficiently sensitive to identify bright Magellanic Cloud Wolf-Rayet stars.