I was reading about cold stars (dead brown dwarves) and came upon this.
What would the density of the star be? Would it actually be liquid? And how exactly would it kill you? Poison? Some weird radiation thing?
Looking at Wikipedia for that star, brown dwarfs and spectral class Y, it looks like we expect to see a lot of methane and even ammonia in the atmosphere of these stars. Overall, brown dwarfs are not all that different from planets like Jupiter.
Of course, the heat alone would be fatal to a person. It may be cold for a star, but touching it would be like dunking your hand in steam/boiling water.
I’m not sure about density - brown dwarfs tend to be about the size of Jupiter and simply get more dense as they get bigger. At only 6-15 x Jupiter’s mass, my guess is that the surface is still quite a bit less dense than water.
Density (at the core) is somewhere between 1 and 100 times that of lead.
It’s made mostly of hydrogen; at these pressures and temperatures, it exists as a supercritical fluid - a kind of hybrid state that embodies the properties of both a gas and a liquid.
Being as you can’t comfortably exist at the pressures and temperatures found in the core of a brown dwarf, things would indeed get ugly for you if you tried to dunk your muffin in that stuff at the core.
The 206F cited in your info is probably the temperature at the surface. Here, “surface” is as ill-defined as the “upper boundary” of earth’s atmosphere: we’re talking about a body of gas that exhibits decreasing pressure and density with increasing altitude - not something you can really dip your muffin into, and not particularly fatal - unless you’re out there inhaling it, in which case you simply die of hypoxia.
What kinda gravity would I feel trying to scoop a cup of joe from the surface of such a star?
And yeah: Is it done radiating any harmfull stuff, like those ultarviolet rays, xrays, whatever?
Well, the Wiki article states that anything over 10 Jupiters in mass is likely to be a brown dwarf, as opposed to a gas giant planet. Jupiter has approximately 318 times the mass of Earth, so if you’re bending down to scoop up a cup of brown dwarf, you’re going to weight around 3,180 times more than you do here. The cup, if it’s eight fluid ounces of water, will weigh approximately 6360 pounds, or more than three tons. If my math is right, which it often isn’t.
To me, that’s not the mind blowing part. The mind blowing part is the following statement from the section on discerning brown dwarfs from stars with stable fusion reactions:
That is, in the atmosphere of at least some brown stars, it rains fucking drops of iron.
Didn’t say if they were molten or not, but with the exception of the coldest brown dwarfs, I expect it would be.
Also, because brown dwarfs (dwarves? I need usage guidelines, people!), no longer have fusion reactions, they do not emit x-rays or ultraviolet radiation. My understanding from the article is that they don’t emit visible light either. They do, however, emit heat, as do large gas giant planets like Jupiter and Saturn.
Hm. I think I’d rather try living on this star, which they believe has a pleasant, summery temperature of 80 degrees! Wild stuff.
Remind me never to drink this writer’s coffee, that’s insanely hot for coffee (by comparison Ms Liebeck’s famous cup of coffee was between 82-88º Celsius).
You wouldn’t weigh 318 times as much “on” Jupiter. Jupiter may be 318 times as massive as Earth, but it’s also a lot bigger. The surface gravity of Jupiter is only 2.5g, and the surface gravity of the Sun is only 28g, although the Sun is 333,000 times more massive than the Earth. The Sun and Jupiter are mostly hydrogen, so they are much less dense than the Earth.
To get a body with a mass 318 times the Earth’s with a surface gravity of 318g, it would have to be exactly the same size as the Earth. That would mean it would have to be 318 times as dense as the Earth.
For Starbucks coffee thats pretty damn cool.
And “dwarves” is the proper plural for short bearded folks with battleaxes, but “dwarfs” is the proper plural form for small stars.
And JRRT’s actual preferred term for more than one dwarf is dwarrows. 
The Letters of JRR Tolkien Letter # 17 To Stanley Unwin, Chairman of Allen and Unwin, p. 23, 24
So how was the gravity on this planetoid so intense? A Mission of Gravity
The equatorial gravity is only 3G; it’s at the polar regions that the extreme 700G is reached. Clement made Mesklin a crazy oblate shape to get the dimensions needed for the two extremes.
Isn’t that how Ray Palmer became the Atom?
I did say my math is often incorrect. Though, in this case, it was more my conceptual understanding of mass vs. density that was the problem.
I’d rather live on this asteroid, although I suppose I’d get lonely.
For ANY commercially available coffee at retail, that IS cool.
Hot enough to make me lose my taste for a day.
And THAT is from a guy who thinks that 104 degrees F is a good bathwater temperature.
That’s a lot of heat, Mr. Lobster. I couldn’t even get near a shower with that. Have you ever drunk your morning coffee in the tub? Then you could add a little more Kelvins.
The thing is, gas giants and brown dwarfs (brown dwarrows?) don’t have a hard surface. So they compute the “surface” gravity as that at the top of the clouds. Similarly, regular stars (which also don’t have hard surfaces) have their gravity computed at the photosphere (point where the atmosphere becomes opaque). All these objects have extensive atmospheres, so the place they are calculating the gravity at is fairly far from the center. Which means their surface gravities are rather low compared with their masses.