Though they are real stars – not just some fictional astronomical phenomena conjured up in Gene Roddenberry’s Star Trek – are Y-Class brown dwarf stars truly qualify as the coolest stars ever in terms of temperature?
By: Ringo Bones
Given that a star’s spectral class / color temperature can now easily determined after seeing it and taking spectroscopic , bolometric and other tests via that “Oh Be A Fine Girl Kiss Me Smack” mnemonic device. But it seems we still have to add another letter to than mnemonic device to accommodate recently discovered new classes of stars that – if you were to excuse the pun – are actually very cool. The latest stellar spectral type classification mnemonic had to be changed and now goes as: “Oh Be A Fine Girl Kiss Me Less Tongue, Yo”.
Discovered back in 2011 by the onboard astronomical instruments on the Wide-field Infrared Survey Explorer or WISE spacecraft that “see” in the infrared portion of the electromagnetic spectrum, Y Class Brown Dwarf stars were said to be the coolest stars discovered to date. Despite the existence of clouds of iron vapor being picked up by the WISE spacecraft’s instrument and “snow” made up of iron filings on a Y-Class Brown Dwarf star it is studying, the mean surface temperature of the said star is only 80 degrees Fahrenheit - a temperature cool enough to be touched with one’s own hands.
Basing on the data gathered so far astronomers believe that Y-Class Brown Dwarf stars are believed to be an intermediate stage between planets and stars. They are on average bigger than the planet Jupiter. While some astronomers label them as “failed stars” – as in stars not big enough to have the requisite gravity to initiate full blown fusion to burn hot enough to be a bona-fide star.