V Sge: Supersoft Source or Exotic Hot Binary? I. An X-Shooter campaign in the high state

Pasi Hakala, Phil Charles, Pablo Rodríguez-Gil

V Sge is a peculiar, highly luminous long-period (12.34h) binary star that can display a super-soft X-ray emitting component when in the faint phase of its V~ 10-13mag variability…