Messier 78: a reflection nebula in Orion
The reflection nebula Messier 78 takes centre stage in this image taken with the MPG/ESO 2.2-metre telescope at the La Silla Observatory in Chile. It lies about 1,350 light-years away in the constellation of Orion and can be found northeast of the easternmost star of Orion’s belt. The brilliant starlight ricochets off dust particles in the nebula, illuminating it with scattered blue light.
The pale blue tint seen in the nebula in this picture is an accurate representation of its dominant colour. Blue hues are commonly seen in reflection nebulae because of the way the starlight is scattered by the tiny dust particles that they contain.
A thick band of obscuring dust stretches across the image from the upper left to the lower right, blocking the light from background stars. In the bottom right corner, many curious pink structures are also visible, which are created by jets of material being ejected from stars that have recently formed.
Two bright stars, HD 38563A and HD 38563B, are the main powerhouses behind Messier 78. However, the nebula is home to many more stars, including a collection of about 45 low mass, young stars (less than 10 million years old) in which the cores are still too cool for hydrogen fusion to start, known as T Tauri stars.