How long has Gliese 581 been in the neighborhood of Sol?

Question

Stars move, you know...

Answer 1

The source says it is currently approaching Earth at 9.5 kilometers per second. By my calculation that is one light year every 31,578 years. So 31,578 years ago it was 22.5 light years away instead of 21.5 light years away. And in another 31,578 years it will be only 19.5 light years away. But it isn't headed directly at Earth. I haven't done the trigonometry to calculate how close it will pass, but at some point it will pass at whatever distance it will miss by and then move away in the opposite direction from which it approached.

OK, I did the trig. and determined that it will pass Earth at a distance of 5.4 light years in 644,505 years.

Answer 2

One would have to know, by a doppler shift method, if the star is advancing or receding from us. Get on the web and try to find out.

The star is Gliese 581, already known to be home to a planet of Neptune mass and a possible third world about eight times as massive as Earth. It’s an M-class red dwarf, far smaller and cooler than the Sun. The new planet, the smallest found up to this point, orbits it in 13 days. Gliese 581, it should be noted, is comparatively close to our own Solar System, about 20.5 light years away in the constellation Libra.

Answer 3

Yes, they move, but they have really big neighborhoods, so Gliese 581 has been in the 'hood longer than you have. I don't want to research a serious answer, but you know it has been a loooong time.

Answer 4

considering interstellar distances and the fact that the star is a dwarf (meaning its probobly old) i would have to say its been in our neighborhood for quite some time. it really depends on what you call our "neigborhood" being an astronomer, i consider our neighborhood to be within 100 lightyears. but thats just me!!!!!