Star Cooler Than Venus Found

crossconnects writes to mention that Discovery is reporting that astronomers have found a nearby star with a mild surface temperature of 660 degrees fahrenheit. "The spectacularly unspectacular object is of special interest because it falls right smack in the middle of the final frontier that divides mega-planets from the puniest stars. Stars in that realm theoretically qualify as an entirely new stellar type -- what's called a Y class dwarf."

Comments

Nuclear fusion?

[smolloy]

I thought the definition for a star was that there had to be fusion occurring at its core. TFA doesn't mention it, but I'm amazed that this object can be this cool, yet still have a nuclear furnace at its heart.

Fascinating stuff indeed.

Sigh, Bad English / Hmm - Biosphere?

[TexVex]

FTA: That means any water in there atmospheres will condense into droplets of water vapor

Aside from the bad English, the quoted bit is actually the most interesting part of the article. Does that mean that a particularly low-temp one of this newly discovered kind of dwarf star could be a self-contained biosphere, with a source of heat in the center surrounded by a life-sustaining atmosphere with liquid water in it?

Dyson Sphere is to Ringworld as Cool Dwarf is to Smoke Ring! :)

Re:Sigh, Bad English / Hmm - Biosphere?

[strack]

Radiation? The only radiation source is fusion at the core of the star, The only thing this star radiates is Infrared. i.e. Heat. to get any ionizing radiation, youd prolly have to be near the core. It probably looks like a particularly active really big gas giant.

Re:Fahrenheit

[duffel]

What, they should have used Rankine? Well, in the context, it makes about as much sense as the Kelvin scale... an arbitrary step size with absolute zero being the zero point. Sounds sensible to me! Probably would be better than Celsius or Fahrenheit. Alas, Kelvin got there ten years earlier, so it's the Celsius scale's step size for the accepted absolute scale. Still a bit arbitrary. Perhaps we should come up with a new scale that encompasses absolute zero and a very well defined temperature that makes sense on an absolute/astronomical level? Perhaps a logarithmic scale? Any ideas?

Re:Fahrenheit

[jd]

The "temperature" of the Big Bang is the theoretical hottest you can ever get, since at that point all mass was in the form of energy, and therefore you had the maximum energy at the maximum density. Nothing can ever exceed that. Thus, if you knew what that was, you could assign it a fixed value as your upper end of the scale. The ideal would be to then have a set of functions (linear, logarithmic, whatever), where a given function was selected for a specific type of application, with the exception of some specific function chosen as the 'standard'.