Star formation history of CMa R1: I. Wide-field X-ray study of the young stellar population

Understand

The CMa R1 star-forming region contains several compact clusters as well as many young early-B stars.

• It is associated with a well-known bright rimmed nebula, the nature of which is unclear (fossil HII region or supernova remnant).
• To help elucidate the nature of the nebula, our goal was to reconstruct the star-formation history of the CMa R1 region, including the previously unknown older, fainter low-mass stellar population, using X-rays.
• We analyzed images obtained with the ROSAT satellite, covering ~5 sq.