Alpha Centauri System

Tiny points of light, with a magic all their own.
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Christopher K.
Posts: 5984
Joined: October 12th, 2009, 3:28 pm
Location: Baton Rouge, LA

Alpha Centauri System

Post by Christopher K. »

The three-star Alpha Centauri system is the closest stellar neighbor to the Sun. Alpha Centauri A and B are separated by about 23 AU; Uranus' orbit would just fit inside that area. The A-B pair are very similar to the Sun and are only slightly older, although Alpha Centauri A (Rigel Kentaurus) is 50% more luminous.

It takes only a moderate-sized telescope (in a dark sky, of course) to see this as a double. Of course, you also need the right latitude, which most North Americans don't have! Proxima Centauri, the third star, is a whopping 8500 AU from Alpha Centauri A and takes at least 750,000 years to orbit.

In 1839 Thomas Henderson first published Alpha Centauri distance of a little over four light years while at the Cape of Good Hope.

Here's a March 2003 ESO image used recently as an APOD...
http://www.eso.org/public/news/eso0307/

More information:
http://stars.astro.illinois.edu/sow/rigil-kent.html
Burnham's Celestial Handbook, pp. 549-552.
Christopher K.
Posts: 5984
Joined: October 12th, 2009, 3:28 pm
Location: Baton Rouge, LA

Re: Alpha Centauri System

Post by Christopher K. »

Today's APOD is an image of Alpha Centauri; a planetary nebula and other treats are included in the field of view. I don't know too much about the astrophotography process, so I don't know if the "glare ring" in the picture is due to Alpha Centauri's being a binary system.

So near and yet so far. During these times...
11pm on 1 June
10:05pm on 15 June
9:10pm on 30 June
...the star is one degree below the Baton Rouge horizon.

The image:
http://apod.nasa.gov/apod/ap120628.html
Christopher K.
Posts: 5984
Joined: October 12th, 2009, 3:28 pm
Location: Baton Rouge, LA

Re: Alpha Centauri System

Post by Christopher K. »

A 10 February announcement revealed to the populace the presence of Proxima Centauri d. Discovered using the radial velocity method (and lightest planet discovered with that method), the planet orbits Proxima Centauri every five days in that star's habitable zone.

More information:
June 2022 Astronomy, pp. 8-9.
https://www.space.com/proxima-centauri- ... -candidate
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