'Bloop' or 'Ker-plunk'

[Timsup2nothin]

Yeah, I mean IIRC Jupiter would need many times its current mass to kick off stellar ignition. And the only convenient place to find that much mass would be the Sun. Earth alone wouldn't come close.

I misread the thing I found. On further review, the point was that Jupiter is as big as a planet can get. Add more mass and the increased gravity shrinks the big gas ball. This could lead to serious consequences, but not ignition in the star sense. The problem is that as the atmosphere gets more dense it becomes more opaque to the heat that is generated in the depths, so you get increasing temperature as well as pressure. Again hypothetically, there would be cycles of contraction and "blow offs" until you reached some equilibrium level, but Jupiter the gas giant would wind up significantly smaller in terms of both size and mass.

For the record, I found a number of references that say the minimum for actual star style ignition is about 13 Jupiter masses.

 

[Lexicus]

For the record, I found a number of references that say the minimum for actual star style ignition is about 13 Jupiter masses.

Yeah, I'm getting wildly varying numbers when I try to look this up on Google, so I just hedged and said 'many'. I saw 80x, and 60x, and I remember seeing 13x and 18x and 16x in the past, so I have no idea.

 

[Bootstoots]

Is it a brown dwarf that's out there as our possible dual sun system?

We've conducted a whole-sky infrared survey with the WISE satellite, and the combination of that and other infrared astronomy means we can pretty much rule out any real brown dwarf companions. But there could easily be very distant planets, such as the hypothesized Planet Nine, or even giant planets at Oort cloud distances.

 

[Bootstoots]

Yeah, I'm getting wildly varying numbers when I try to look this up on Google, so I just hedged and said 'many'. I saw 80x, and 60x, and I remember seeing 13x and 18x and 16x in the past, so I have no idea.

There are two different thresholds. At about 13x Jupiter's mass, a body can fuse deuterium nuclei together but cannot fuse normal hydrogen. That's the dividing line between brown dwarfs and sub-brown dwarfs/planets. At about 75-80x, the proton-proton chain reaction starts, and that's the dividing line between brown dwarfs and red dwarfs. I think most people consider a true star to be a body massive enough to fuse regular hydrogen as an energy source, with brown dwarfs in a sort of middle ground between planets and stars.

 

[CavLancer]

We've conducted a whole-sky infrared survey with the WISE satellite, and the combination of that and other infrared astronomy means we can pretty much rule out any real brown dwarf companions. But there could easily be very distant planets, such as the hypothesized Planet Nine, or even giant planets at Oort cloud distances.

Suddenly I feel kinda...lonely and...:sniff:...vulnerable. Think its time for my safe space thread.

Thanks for the link, I'll check out planet 9.

 

[Perfection]

Kerbloop

 

[CavLancer]

Kerbloop

Ah yes, what was I thinking? This is the answer.