Emission nebula in the constellation Ara
NGC 6164, known as the Dragon's Egg Nebula, is an emission nebula located in the constellation Norma. The nebula was discovered by astronomer John Herschel in 1834, and is approximately 3,870 light years from the solar system.
Its shape gives it the appearance of a planetary nebula resulting from the death of an old star similar to the Sun, but it is in reality an emission nebula. The gas from this nebula was ejected by the star located at its center, and this is also the source of its energy. In the Henry Draper Catalogue, this star is designated as HD 148937. It is a very young O-type star whose age is between three and four million years. Surrounded by its magnetic field, this star is about 40 times more massive than the Sun, and is expected to end its life on the main sequence in three to four million years.