The Astronomy Thread

[icekatze]

hi hi

Are they not including "hot Jupiters," in their results? I can think of some other hypotheses that involve planets getting shuffled around at some point.

I guess the Earth and Venus are pretty close together in size, though I'm not sure they're that alike in composition. That being said, I suppose if there were a boundary between heated expanding material and cooler in-falling material, that would make a great place to form planets. If a group of planets did have the same composition, it they might at least all have similar conditions for life to evolve.

From what I've read, there's a lot of debate over where the crossover between "super-Earth," and "Neptune-like," body might be, if there even is one. There's certainly the possibility that a body that massive would be able to hold onto most of its hydrogen and probably all of its helium, unless it was much hotter than Earth.

I guess we just gotta keep building bigger telescopes.

[Arioch]

They've found many systems with "hot Jupiters," because they're especially easy to detect, but I think it's universally accepted that these are systems where the gas giants formed in the outer solar system and then migrated inward. It's probably not possible for a gas giant to form very close to the star, as the solar wind would blast away the gas and volatiles in the disc before it could coalesce.

All the exoplanet data we have is pretty much limited to size and mass; we don't really know anything about composition. They are starting to get some data on atmospheres for planets that transit the star, but that still doesn't tell you much about what the planet itself is made of, and bigger telescopes won't change that. But it stands to reason that planets that formed near each other (especially if they formed from the same ring and then migrated inward) would be composed of similar materials.

[Arioch]

This is a fun one. Six-star triple-binary system.


https://exoplanets.nasa.gov/news/1672/d ... -eclipses/

[GeoModder]

I realize the stars of such short-timed binaries are still millions of kilometers apart, and the orbit time is only so short because of the masses involved, but my gut always asks me why they don't merge.

[Demarquis]

Anyone following the story about the largest continuous explosion in the universe ever found? Supermassive black hole eating a gas cloud. No pics, sadly.

[Arioch]

I realize the stars of such short-timed binaries are still millions of kilometers apart, and the orbit time is only so short because of the masses involved, but my gut always asks me why they don't merge.

As with planets and moons, if they were close enough to merge, they would have already. (Or, perhaps more likely, they wouldn't have formed as distinct bodies in the first place).