Strange question time- cutting the Sun in half.

[Iroscato]

Random question that just popped into my head. What would happen if some monstrously powerful force neatly bisected the Sun right through its corona, surface and core, then took away one half? Obviously the planets and their orbits would be fucked, but what would happen to the star itself? Would it explode from pent up pressure in the core? Would it manage to reform into a smaller star?

[Singular Intellect]

My immediate layman interpretation of such an event, which I assume you to mean happens practically instantly, results in the remaining matter rapidly reforming itself into a much smaller star with half the mass.

I'll leave it to the more knowledgeable here to explain whether it would be a self sustaining one or how far off the mark I am.

[Iroscato]

My immediate layman interpretation of such an event, which I assume you to mean happens practically instantly, results in the remaining matter rapidly reforming itself into a much smaller star with half the mass.

I'll leave it to the more knowledgeable here to explain whether it would be a self sustaining one or how far off the mark I am.

Yes, I did mean instantly, thanks for pointing it out.

[Korto]

For another layman's guess, before the big boys arrive:

The centre of the sun explodes out into the missing side, due to the immense pressure with no longer anything holding it back, probably exploding out a fair way. This may propel the sun sideways a bit.
The outer layers, bereft of the support of the inner, collapse inwards.
Whole thing explodes in a way similar to a supernova.

[madd0ct0r]

Imagine squeezing half a lemon...

[Borgholio]

A type 1 supernova frequently occurs when a small star like our sun merges with another star, rapidly increasing the mass and causing an explosion.

Since this scenario is the opposite, I'd classify it a type 0.5 supernova.

[Iroscato]

Cool, thanks guys. Expect more random questions in the future.

[Eternal_Freedom]

A type 1 supernova frequently occurs when a small star like our sun merges with another star, rapidly increasing the mass and causing an explosion.

Since this scenario is the opposite, I'd classify it a type 0.5 supernova.

Sorry, but thats just wrong. Type I and Type II supernova are differentiated by their spectra, not what happens.

I think you mean Type Ia, but even that isn't right in this case. Type Ib, Ic and II are the massive-star core-collapse supernovae, Type Ia is when a white dwarf crosses over the Chandrasekhar limit and becomes a neutron star.

At most this would give you an ordinary nova, a sudden brightening of a star that then fades over time. The exposed core region would expand violently outwards, quite possibly at escape velocity or above, meaning all that mass (and in the sun's core, that's a lot) would be ejected out into the solar system. Think a Coronal Mass Ejection on an apocalyptic scale.

The remaining mass would probably coalesce into a new, half-solar mass star, but I think it would take a while for enough pressure to build up to start fusion again. If the delay is too long, we die.

Worse, the sun is now half it's mass, which means all the planet's are no longer in stable orbits. Worse, the sun (if it continued to shine) will now be dimmer and cooler, hence the habitable zone will change and Earth will become a dead wasteland like Mars.

Basically, it's game over for Mankind.

[Borgholio]

You're right, I meant type 1a. I was going by the premise that if a type 1a supernova is caused by an increase in mass, then an explosion caused by a loss in mass (cutting the star in half) would jokingly be called a type .5 supernova.

With that being said, I would expect most of the core to explode violently away from the remaining shell of the star. If anything remains to collapse again, would it even be enough to be a brown dwarf?

[Eternal_Freedom]

The smallest main-sequence stars we've seen are in the range of 0.08 solar masses, so it's quite possible that enough mass will remain to form a main-sequence star. That being said, it will be dim, red, cool and probably not even Mercury would be in the habitable zone. Earth becomes a frozen wasteland, even if the sudden orbital chaos doesn't eject it from the solar system.

On the plus side, the Sun would suddenly gain a much longer life expectancy.