SFO 75 - The Coffee Bean Nebula

SFO 75 (RCW 98), the Coffe Bean Nebula,  is a Bright Rimmed Cloud (BRC) from the Sugatani, Fukui, & Ogura catalog.  It is a ring type nebula centered on a Wolf-Rayert star.  Radio telescope observations reveal the presence of a dense core embedded within each cloud, and the presence of a layer of hot ionised gas coincided with their bright-rims. The ionised gas has electron densities significantly higher than the critical density above which an ionised boundary layer can form and be maintained, strongly supporting the hypothesis that these clouds are being photoionised by the nearby OB star(s).  This radiation driven implosion promotes abundant star formation.