APOD 3.5 Flame Nebula Close-Up

The Flame Nebula, aka NGC 2024, is in the constellation Orion and is 1500 light-years away from the Orion molecular cloud complex which also includes the Orion Nebula. This cloud is what makes the reddish color of the Nebula. The glow is caused by ionized hydrogen recombining with electrons. The source of the Flame's energy is hidden by the dark dust cloud in center of the picture. However in infrared, hot young stars are found behind the cloud and at least one of these stars is the cause of the energy.