Merak (Beta Ursae Majoris)

Merak (Beta Ursae Majoris) is a main sequence A star that is the fifth brightest in Ursa Major and also one of the 'Pointers' that, together with Dubhe, just to the north, leads the way to Polaris, the North Star. Merak's anatomically precise name comes from an Arabic phrase meaning 'the flank of the Greater Bear.' Like Vega, it radiates excess infrared that seems to come from a disk-like shroud of heated dust, similar in size to the orbit of Saturn and having a temperature of a few hundred K. Merak is part of the Ursa Major Moving Cluster.


visual magnitude 2.34
absolute magnitude 0.41
spectral type A1V
surface temperature 9,000 K
luminosity 60 Lsun
mass 3 Msun
distance 79 light-years
position RA 11h 01m 50.5s,
Dec +56° 22' 57"