NGC 1977 is a complex nebula containing
a diffuse reflection cloud and a bright HII region. It comprises
the southern portion of S279, a more extended HII region 30 arc
minutes north of the Orion Nebula. The stars of NGC 1977 are part
of the Orion 1d subgroup, the youngest members of the Orion OB1
stellar association. NGC 1977 is bounded on the south by the extreme
northern end of the Orion A Molecular cloud. The lone exciting
star of NGC 1977 and the surrounding HII region, S279 is the B1
V star HD 37018 (42 Ori). This star and the other bright stars
of NGC 1977 make up the youngest subgroup (subgroup d) of the
Orion OB association. The stars in this region are between 2 and
4 million years old. The region of NGC 1977 represents the northern
boundary of the OMC-2 and OMC-3 molecular cloud cores which is
one of the most active sites of low and intermediate mass star
formation known. A large number of energetic outflows, Herbig-Haro
objects, and embedded protostars have been found in this region
between NGC 1977 and M42-43 mostly at infrared wavelengths. The
bright rim along the southwestern edge of NGC 1977 represents
the interface of the nebula with its molecular cloud complex.