The deep OB star population in Carina from the VST Photometric H$\alpha$ Survey (VPHAS+)

M. Mohr-Smith, J. E. Drew, R. Napiwotzki +10

Massive OB stars are critical to the ecology of galaxies, and yet our knowledge of OB stars in the Milky Way, fainter than $V\sim 12$, remains patchy. Data from the VST Photometri…