The formal discovery of Helium was made in 1895 by well-named Swedish chemists Per Teodor Cleve and Nils Abraham Langlet, though it was first detected in 1868 by French astronomer Pierre "Jules" César Janssen, who observed a yellow spectral line signature in the sunlight during a solar eclipse. English scientist and astronomer Joseph "Norman" Lockyer shares this credit and is responsible for Helium's name — let's all be glad he was a classical namer and not a narcissist — or we'd all be filling birthday balloons with Lockyerium.
There are many names with sunny meanings — Japanese Youko/Yoko can be written with the characters for either "sunlight" or "ocean" combined with the suffix "-ko," meaning "child." Haru is a Japanese male name that can be written with the character for "sunlight," and Haruki adds the suffix "-ki," which can mean "to shine/radiance" or "life." Heulwen ("sunlight") and Tesni ("warmth of the sun") are pretty, feminine Welsh names, and Solveig ("sun strength") and Sunniva ("sun gift") are Norwegian. I love the look of variant Synnøve, too.
Names with a plain "sun" meaning include French Soleil, Lithuanian Saulė, masculine Ravi (a Hindu god of the sun) and Croatian Sunčana. Speaking of other sun gods and goddesses, Arinna was a Hittite sun goddess, and Surya (also called Aruna) is the Hindu equivalent of Greek Helios. Étaín (also found as Éadaoin) is the name of a sun goddess and heroine of Irish myth, and let's not forget the French sun-king name Louis, which I've previously featured.