Young Star convergence

These files demonstrate the property of convergence for nearby young associations (Zuckerman & Song 2004, Torres et al. 2008).  When their proper motions of stars in a moving group are extended into full great circles (surrounding the sky), all the great circles intersect at two points: the convergent point, and the divergent point.  Those points are equivalent to the vanishing points we're familiar with in parallel train tracks seeming to converge.  This is not true of stars in general (represented here by stars within 25 pc of the Sun). 

Also shown on most of these graphs are the solar (northern hemisphere) and anti-solar (southern hemisphere) points; these are the directions the Sun is moving toward and away from.  We are moving THROUGH the clouds of young stars, which is why most of them converge near the anti-solar point.