KIC 8462852 Observations Options

[JRehling]

Kepler found one very, very strange case:

http://www.theatlantic.com/science/archive...-galaxy/410023/

In a nutshell, while Kepler was observing it, the star (larger and brighter than the Sun) exhibited four dimming events that took place at irregular intervals, blocked a lot more light than a Jupiter-sized planet would block, and had a "shape" that varied in all four cases and did not resemble a planet.

This case is attracting some wild speculation… in fact, it is seemingly certain that something wild must be going on; it's just a matter of which wild scenario is the correct one.

If I had to throw my hat in the ring, I'd guess that a distant collision and breakup has placed big swarms of matter into a very long-period orbit. But there's no hypothesis that's been offered that doesn't seem problematic.

[Explorer1]

Yes, just as I suspected. I did a quick search t to find out if there were any journal articles, but found nothing. Looks like yet again truth is stranger than (science) fiction.

[JRehling]

There are probably some planets made largely/entirely of gaseous rock and/or metal, which is pretty strange to consider. But I'd be very surprised if we find any planets much denser than iron (that is, iron's various denser states, under pressure). Iron is far more common than any elements heavier than iron, and I can't think of many processes that would discard iron and keep the heavier stuff. The center of the Earth's core is modeled to have a density of about 14 g/cm^3. I think the absolute maximum for any extrasolar planets would be around that level or less.

[HSchirmer]

...I can't think of many processes that would discard iron and keep the heavier stuff.
... I think the absolute maximum for any extrasolar planets would be around that level or less.

Well, what about a white dwarf that hits something and goes splat.

So, is there an inverse of the Chandrashekar limit, that requires small pieces of electron degenerate matter revert to "ordinary" matter below a specific mass? I recall theories about chunks of material made with charmed or strange quark properties remaining stable once formed

[JRehling]

Well, what about a white dwarf that hits something and goes splat.

The escape velocity of a white dwarf is about 6,000 km/s, white dwarfs have a mass of over 100 Jupiters, and collisions are inelastic. That is never going to produce planets.

[HSchirmer]

The escape velocity of a white dwarf is about 6,000 km/s, white dwarfs have a mass of over 100 Jupiters, and collisions are inelastic. That is never going to produce planets.

Agreed. You can't hit a white dwarf and break it up, unless you have a really big hammer.
Consider a white dwarf in a loose binary system where the other star goes supernova.
That shock wave should disrupt the dwarf, possibly leaving planetary mass chunks, or blasting it into smaller chunks.
Since we see planets around pulsars, even after a supernova, the disrupted material should reform planetary mass objects.

I'm not sure what the minimum gravitational force is to keep degenerate matter "packed down", thinking about it, it would seem
that the degenerate matter would "re inflate" violently when a white dwarf is disrupted.

[JRehling]

Consider a white dwarf in a loose binary system where the other star goes supernova.
That shock wave should disrupt the dwarf, possibly leaving planetary mass chunks, or blasting it into smaller chunks.

It's probably not the strongest use of this board to offer qualitative assumptions about never-observed phenomena. The outcomes of huge, cosmic collisions require pretty detailed research to determine, and math-free estimates of how they would proceed doesn't seem likely to be productive. A little math suggests to me that a supernova would not break a white dwarf apart, but that's not really on-topic for this board even if the issue were investigated thoroughly, much less when assumptions are made without math.