the time when the sun is farthest south from the celestial equator occurring around December 21st
the boundary around a black hole on and within which no matter or radiation can escape
any of the nine large heavenly bodies revolving about the sun and shining by reflected light: a similar body revolving about a star other than the sun
the brightness of a star in comparison with that of the sun: the luminosity of Sirius is expressed as 23 and indicates intrinsic brightness 23 times greater than the sun
the gaseous envelope surrounding a heavenly body
used to designate the brightest star in a constellation