FWIW, Info. on our nearest neighbours. Alpha Centauri & companions. Alpha 'A' 'B' & 'C' or 'Proxima'.
http://www.solstation.com/stars/alp-cent3.htm
http://www.glyphweb.com/esky/default...acentauri.html
& on Beta Centauri. Another double system.>
http://en.mimi.hu/astronomy/beta_centauri.html
http://www.daviddarling.info/encyclopedia/H/Hadar.html
Check out the orbits links. Very interesting stuff.
http://www.solstation.com/orbits/ac-absys.htm
Easy for you Dave. Children will like it.
L.