NGC 2023 (also designated LBN 954) is a diffuse reflection nebula of some 4 light-years across, located 1467.7 light-years away on the south of the Orion B molecular cloud, very close to the Horsehead Nebula (Barnard 33), in the constellation Orion.
This nebula is actually surrounding, and powered by the large blue-white B type star HD 37903, which is the most luminous member of a cluster of young stars. B type stars typically have a surface temperature somewhere in the range of 11,000 – 25,000 Kelvin. In comparison the Sun has a temperature of 5,000 Kelvin.
NGC 2023, one of the largest and brightest sources of fluorescent molecular hydrogen, is a region where star forming is taking place actively.
Image Credit: ESO/J. Emerson/VISTA/Cambridge Astronomical Survey Unit