The reflective fog M78 is from us at distance of 1600 light years in the constellation of Orion. At observations in visible light she looks as the bright blue cloud surrounded with dark dust strips. Dust reflects and scatters light radiated by young stars in M78 kernel. As a matter of fact, therefore a fog also call reflective.
Fortunately, the astronomy has gone beyond visible light long ago. Observations in IR spectrum allow to get for a dust veil and to see the bright stars hidden inside. For example, two sverkhigigant of HD 38563A and HD 38563B which, as a matter of fact, also highlight a fog.
It is possible to consider also a supergiant of HD 290861 in next the fog NGC 2071. The IR spectrum also allows us to see the mass of the stars which are formed in clouds of dust. In a picture they are well noticeable in the reddish and yellow color. Some of them are stars of type T of the Taurus. So call young stars which temperature in a kernel is still insufficient to start thermonuclear reaction. They emit energy due to gravitational compression.