The Horsehead Nebula region

Horsehead Nebula

Horsehead NebulaHorsehead Nebula region (Canon 700D, Canon EF 200mm 1:2,8 L II USM, 138 stacked 30 second exposures).

The Horsehead Nebula is a higher density area in the Orion molecular cloud B (GMC B) which is eroded by the intense radiation coming from the nearby star Sigma Orionis. The hot and luminous O-type star is also responsible for the red emission nebula/HII region IC 434 in front of the Horsehead Nebula region.

Close to the Horsehead Nebula is the Flame Nebula (NGC 2024). The region is an emission nebula very similar to the Orion Nebula but of smaller size and younger age. The central stars of the Flame Nebula cluster are still hidden behind an opaque dust band and can only be seen in the infrared spectral range.

NGC 2023, IC 431, IC 432 and IC 435 are smaller reflection nebulae and belong to the same star forming region. The brightest star in the picture is Alnitak, one of the three stars that form Orion’s belt. The ultra-luminous O-type star is possibly also a member of the Orion star forming region. The observed distance to Altinak is however quite uncertain and there is also the possibility that Altinak is a foreground star and not astrophysically related to the Horsehead star forming region.