8.7 ly Beta Sirius 8.3 white dwarf . Distances to stars are difficult to measure accurately. There are a dozen stars at distances of 11-12 light years. Magnitude is the measure of apparent brightness as seen from earth, the larger the number the dimmer the star appears. A decrease of 2.5 in magnitude means the star appears 10 times as bright.
Many stars have variable brightness.
Stars with magnitudes beyond 6 are difficult to see without binoculars or a telescope. The spectral class of a star attempts to determine its temperature, mass and size from its color and brightness. Hours and minutes of right ascension are measured clockwise around Polaris, starting with the sun's position at the vernal equinox. One minute of right ascension is fifteen times as great an angle as one minute of declination. The values given for ascension and declination are for January 2000.