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frenchtoaster t1_irvxkm0 wrote

Reply to comment by FluffyTid in The vast majority of the 150-400 billion stars in the Milky Way haven't been directly detected. Alpha Centauri is the nearest known star to Sol. What is the probability that there are nearer stars that remain undiscovered? by [deleted]

The question said closest star to Sol, not to Earth. Unless you mean like the person nearest to you is you at distance zero.

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greyl t1_irw30em wrote

No, he's saying the closest star to Sol isn't Alpha Centauri it's Proxima Centauri.

It's pretty confusing though because "Alpha Centauri" is a 3 star system and the individual stars within Alpha Centauri are named Alpha Centauri A, Alpha Centauri B, and Proxima Centauri.

https://en.wikipedia.org/wiki/Alpha_Centauri#Stellar_system

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Aenyn t1_irw4gti wrote

So in a few hundred thousand years it will be Alpha Centauri AB that will be the closest stars to our system?

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skibble t1_irw6r18 wrote

I'm confused. AB are a binary, orbiting their center of mass. Proxima is closest to Sol. How is Proxima gravitationally related to AB? If she were orbiting them, wouldn't she sometimes be closest and sometimes be furthest?

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hilburn t1_irw7atx wrote

Proxima orbits AB with a period of ~550,000 years.

So the "sometimes" is a while, and includes for as long as we've been measuring things

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Oknight t1_irw7odq wrote

The orbital period of Proxima makes it the closest star to Earth for a much longer period than human beings generally care about. Eventually even the Alpha Centauri system including Proxima won't be the closest stars to Earth and the time frame for that isn't all that much larger than a Proxima "year". In less than 3 Proxima years Gliese 710 will pass only 90 Light Days from Sol.

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NavierIsStoked t1_irwg9b5 wrote

>90 light days from Sol

That seems to be well within the Oort Cloud. I would assume that could cause some objects to get directed into to the solar system. Hopefully we will still be around to care.

Reading the wiki about 710, it seems there is an 86% chance of going through the Oort Cloud. I noticed it didn’t say anything about what 710 would be dragging with it. I assume all stars have some kind of Oort Cloud.

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