|Right Ascension||05 : 46 : 46.0 (h:m:s)
|Declination||+00 : 04 : 12 (deg:m:s)
|Apparent Dimension||7 (arc min)
Within the reflection nebula M78 in Orion, hidden in visible light, lies a young open cluster of stars which have recently formed in that region of the giant Orion Cloud of interstellar matter. This cluster was observed and studied by Lada et.al. (1991). It is cataloged by Archinal and Hynes (2003) as "[LDEG91] 3" and reviewed, together with other embedded clusters, by Lada and Lada (2003). Observations as early as Strom et.al. (1975) had already shown a number of recently formed young stars in M78 of spectral types from late B to A.
These authors found that the core of M78 has a total mass of about 266 solar masses, of which 113 solar masses have been used up to form about 192 young stars. This cluster is now illuminating the dust and hiding within the reflection nebula, extending over a volume of 3 light-years in diameter at its distance of 1350 light-years. The percentage of about 30% of matter that was used in forming stars is remarkable effective compared to outher star forming regions.
The two brightest stars are HDE 38563A and 38563B.
Last Modification: October 9, 2018