NGC 2170

NGC 2170 is a reflection nebula in the constellation Unicornus. It is the brightest of a group of nebulae associated with young, hot stars.

It is located about 3° west of the star γ Monocerotis, an orange giant clearly visible even to the naked eye, being of magnitude 3.99; its position in the sky is a few degrees east of the Orion Nebula. It can be easily observed with a powerful amateur telescope, in which it shows itself as a bright spot with a star in the center. The star responsible for its illumination is BD-06 1415, a blue star of spectral class B1, which gives the cloud a markedly bluish color. This star is part of the Monoceros R2 association, an OB association linked to a molecular nebula complex called the Monoceros R2 Cloud, whose center is located in the direction of this and other nearby bright clouds; On the whole, star formation phenomena are taking place, as evidenced by the presence of several protostars gathered in a young cluster in formation, jets of molecular gas and sources of infrared radiation and X-rays. The stars of the Mon R2 association were formed during the first cycle of star formation that affected the region, about 6 million years ago; It would have been triggered by an expanding superbubble with a diameter of a few hundred parsecs