Rather the bright star Alnitak, the easternmost star in the Belt of Orion, shines energetic ultraviolet light into the Flame that knocks electrons away from the clouds of hydrogen gas that reside there. Much of the glow results when the electrons and ionized hydrogen recombine.
Additional dark gas and dust lies in front of the bright part of the nebula and this is what causes the dark network that appears in the center of the glowing gas. The Flame Nebula is part of the Orion Molecular Cloud Complex, a star-forming region that includes the famous Horsehead Nebula.
According to a new study, the stars at the center of NGC 2024 were about 200,000 years old while those on the outskirts were about 1.5 million years in age.
Image Credit: ESO/J. Emerson/VISTA. Acknowledgment: Cambridge Astronomical Survey Unit