NASA’s WISE Spots Ys

In the ongoing hunt for things in space that are more and more difficult to find (because scientists love a good challenge), NASA’s WISE spacecraft has revealed something new lurking in the dark: Y Dwarfs.

The newly discovered, though long anticipated, “Y Dwarf” is an even smaller, cooler version of the sub-stellar object called a brown dwarf, with surface temperatures hovering around that of a human body, or even “room temperature.”

Y Dwarf stars are so cool that even the infrared radiation they emit is faint, and it took the new, state of the art instruments on NASA’s WISE (Wide-field Infrared Survey Explorer) spacecraft to detect them. With its highly sensitive IR cameras, WISE has discovered about 100 new brown dwarf stars, with six among them being Y Dwarfs ranging in distance from 9 to 40 light years away.

The imaginative side of me likes the idea: a cool, dark, quiescent “star,” like a large, lone Jupiter, floating in the dark interstices between the showier “main sequence” stars, warmly casting its low-energy heat rays into the stellar community. And perhaps it has planets, too, this dark star; worlds of icy darkness, day and night. By night, the clearest, darkest, starriest skies you can see anywhere; by day, the same, except with a softly glowing magenta “sun” embedded in the glittering blackness….
…but this is not what comes to mind when I think of a star! Stars are supposed to be blindingly bright, incredibly hot, and violently eruptive! Right?

Stars, like planets, belong to a wide, continuous spectrum of physical stature, from the giant “O” class stars with 60 solar masses, 50,000 degree C surface temperatures, and 800,000 times the brightness of our Sun down the scale though the B, A, F, G (our Sun), and K classes, to the small M class stars. M stars possess less than a tenth the mass of our Sun and as little as a thousandth the brightness, being only two to three thousand degrees at the surface.

But below the classical “Oh Be A Fine (Girl or Guy—pick one!), Kiss Me” scale, astronomers have added letters to the scale as they theorized, and eventually observed, even lesser balls of gas that were still too massive to be classified as big planets: L, T, and sometimes Y. Well, not sometimes—not now that WISE has seen six of them, pulling them out of theory into scientific fact.

Beside temperature and mass, one of the attributes astronomers use to help classify these objects is by the abundances, or lack, of certain chemical compounds, like titanium oxide, methane, water vapor—which got me to thinking. It is too hot on our Sun for chemical compounds (molecules) to exist; they would quickly be broken into simple chemical elements (atoms) if they ever appeared there. But Y Dwarfs have surface temperatures not unlike that of the air surrounding you right now, and so more complex molecules can dwell there.

It occurs to me (following a short string of ifs) that, if Y Dwarfs have these Earth-like surface temperatures, and if the heat energy from inside the star is sufficient, and if sufficiently complex molecules could develop, over time, under those conditions—if, if, if—then might it be possible for life to exist on such an object?

Life, on a star? That’s my own musing, nothing more, but how cool would that be?