Bubble Nebula (NGC 7635)
DOI link for Bubble Nebula (NGC 7635)
Bubble Nebula (NGC 7635) book
A faint diffuse nebula in the constellation Cassiopeia, position RA 23 h 20.7 m, dec.+61° 12', appearing as a 3' diameter bubble surrounding a seventh-magnitude star. The bubble is a spherical shell of gas apparently shed by the central star, although it does not appear to have the characteristics of either a planetary nebula or a supernova remnant.