Electronic transitions in this element produce the Pickering series.
Electronic transitions in this element produce the Pickering series. Type Ib supernovae are the only subclass of type I supernovae to possess absorption lines of this element. A phenomenon named for this element occurs when a degenerate core composed of this element reaches a temperature of 100 million Kelvin. The portion of a star consisting of elements heavier than this element is larger for population I stars than for population II stars. Stars move onto the horizontal branch after experiencing a (*) "flash" named for this element. Red giants generate carbon from the fusion of three atoms of this element. Nuclei of this element are formed in the proton-proton chain and by deuterium-tritium fusion--those nuclei are referred to as alpha particles. For 10 points, name this element formed from the fusion of two hydrogen atoms, the lightest noble gas.
Electronic transitions in this element produce the Pickering series.
helium [prompt on "He"]