Sun vs White dwarf

Great!


Something else to worry about!

Neat picture.

When thinking of a black hole passing "through" the Sun, it's beneficial to picture the gravitational well of the objects rather than their "size".

Remember the types of black holes which we have evidence for are much more massive than our Sun. So if one were to approach, *it* would dominate the interaction, not the other way around. For example, the Sun would fall toward the hole more than the hole would fall toward the Sun. And if the hole were sufficiently massive and had a small component velocity, the Sun would follow the hole and eventually settle on top of it, and our Sun would be dragged slowly out of our solar system and consumed by the hole. The planets would also try to follow the hole, and would either be captured and dragged away into the darkness, or they would be disrupted and float into empty space randomly.

The planets would change orbits, but the stream of plasma following the intruder out of the solar system would be narrow and would likely miss all the planets, otherwise, I'm skeptical.
If the velocity difference is one million miles per hour, the sun would deform only a little pre-impact. If the acreation disk had little mater the entrance hole would be small. Close proximity would be too brief for the sun to accelerate more than a few thousand miles per hour.
The more massive black hole quark star, nutron star or white dwarf would not change speed or path more than a bit.
Sun material within about one thousand miles of the surface of the nutron star etc or the event horiozon would steam behind the intruder for millions of miles; perhaps billions, but the sun would loose less than 2% of it's mass unless the colision occured close to the minimum possible speed difference or the intruder had a Jupiter mass plus in it's accreation disk. I have to admit my opinion is more intuition than good math. Neil

Neil - TWO PERCENT on the Sun's mass!!! That's as much as all the non-solar objects in the Solar System. Not to mention an interaction creating massive amounts of X-rays with enough charged particles to fry the Earth.

We build Xray telescopes and gamma telescopes in space because these rays do not penetrate Earth's atmosphere. The gamma flux in a poorly shilded space craft may be a thousand times the flux experienced by the average surface human, so most surface humans would survive unless the GRB was quite close and very strong.The short durration of the burst also increases chances of survivile. Half the galaxy is likely pesimistic except for the one in a million strongest GRB. Neil

Niel you've missed the central point that any star is a finely balanced thing.
The unimaginably massive outward radiation pressure created by the fusion processes going on inside the star are balanced by the inward gravitational pressure of the overlying gas.
This is why stars are spheres. All the pressures are balanced out evenly over the entire volume of the star. Everything is in equilibrium.

Now if you introduce an object that changes the delicate balance of these forces you are going to get disruptions.
Disruptions in the balance of the inward and outward pressures.

This means that at some points the star will collapse inward because of the lessening of the outward pressure. In these areas the nuclear fusion processes will become massively accelerated, the temperature will skyrocket and you will end up with the mother of all nuclear explosions.

In the other areas where the inward pressure is lessened you will have matter undergoing intense nuclear fusion in the interior suddenly finding that the top has been taken off the bottle. So it escapes and you have another astounding explosion.

These two processes will go on simultaneously.

So basically bringing a black hole or a passing white dwarf anywhere near the Sun will tear it to bits and annihilate pretty much anything in it's vicinity.
Like the planets orbiting it.

Just a note:

White dwarf = far more dense than sun

Hi Heliotrope: if you are correct, mini black holes could cause most of the brief but random star brightening we observe, but it also means that fresh hydrogen would fall into the hole in the core delaying the day that the star would go super nova or flare up to be a red giant. Neil

Hi mike: Very high density also means the white dwarf is small, even if it is one solar mass, so I would not expect it to make a huge exit hole, unless it passed though the sun at a million miles per hour or more. Neil