IC 418, also known as the Spirograph Nebula, is a planetary nebula located in the constellation of Lepus about 3,600 ly away from Earth. It spans 0.3 light-years across. The central star of the planetary nebula, HD 35914, is an O-type star with a spectral type of O7fp.[4] The nebula formed a few thousand years ago during the stars last stages of its red giant phase. Material from the star’s outer layers was ejected from the star into the surrounding space. The nebula’s glow is caused by the central star’s ultraviolet radiation interacting with the gas.[5]
The nebula gets its colors from the different chemical elements inside the nebula. The red color is nitrogen (the coldest gas in the nebula), the green is hydrogen and the traces of blue are the ionized oxygen gas (the hottest gas in the nebula due to its proximity to the central star).[6]
Naming
The name derives from the intricate pattern of the nebula, which resembles a pattern which can be created using the Spirograph, a toy that produces geometric patterns (specifically, hypotrochoids and epitrochoids) on paper. The origin of the Spirograph pattern is unknown.[7]
