Timeline for How small a star can provide Sun-level illumination to its planets?
Current License: CC BY-SA 3.0
13 events
| when toggle format | what | by | license | comment | |
|---|---|---|---|---|---|
| Sep 20, 2022 at 15:32 | answer | added | LazyReader | timeline score: -4 | |
| Nov 19, 2015 at 23:07 | history | tweeted | twitter.com/StackAstronomy/status/667479360782409728 | ||
| Nov 19, 2015 at 12:52 | comment | added | Ricky | @RobJeffries: You're absolutely right. I didn't think of that. Thank you. | |
| Nov 19, 2015 at 12:46 | comment | added | ProfRob | @ricky physics.stackexchange.com/questions/165283/… A large "rock" could not maintain its structure against its weight. It would compress and become essentially gaseous, though with an unusual composition. If it then cooled it might though then become crystalline. A white dwarf star could be considered a large "rock" if you count diamond as a rock. The definition of a planet is slippery. | |
| Nov 19, 2015 at 10:32 | comment | added | Ricky | @SF: I looked it up and found out that the smallest possible star's diameter would be 8.7% of the Sun's. Jupiter is actually larger (about 10%). Is there a ceiling for the size of a planet? Or (horror of horrors) are there lone rocks out there that are a million times the size of the Sun that we can't see because they don't produce any light? | |
| Nov 19, 2015 at 10:11 | comment | added | SF. | @Ricky: There's a bottom limit on size of a natural celestial body producing own light of sufficient intensity. Although a sufficiently big artificial satellite made from the right radioisotopes? | |
| Nov 19, 2015 at 10:05 | comment | added | Ricky | @userLTK: "That's an interesting <i>mathematical</i> exercise." Why am I not surprised? ... Hmm ... Suppose the star should revolve around the planet? What then? | |
| Nov 19, 2015 at 9:43 | vote | accept | SF. | ||
| Nov 19, 2015 at 8:04 | comment | added | ProfRob | @userLTK The X-rays are a manifestation of magnetic activity. | |
| Nov 19, 2015 at 1:08 | comment | added | userLTK | Update on the comment above. Reading up on it, most brown dwarf stars won't have a magnetosphere, though (perhaps) smaller or cooler ones might. X-Rays could also be a problem that close to a brown dwarf. en.wikipedia.org/wiki/… | |
| Nov 18, 2015 at 23:52 | comment | added | userLTK | That's an interesting mathematical exercise. There's other factors if you want the planet to actually be earth-like. When you get a star that small and a planet that close, you might find yourself in the heart of an enormous stellar-magnetosphere. Tidal forces are another problem for anything except a near circular orbit and tidal locking would seem very likely too. If the star has sun-spots, and, presumably you'd either have sunspots or a gonzo-magnetosphere, that could be a problem too. Red-dwarf sun-spots can be very intense. The practical limit would be quite a bit larger. | |
| Nov 18, 2015 at 22:00 | answer | added | ProfRob | timeline score: 13 | |
| Nov 18, 2015 at 19:06 | history | asked | SF. | CC BY-SA 3.0 |