We present a new directly-observable statistic which uses sky position ( x,y ) and proper motion ( v _ { x } ,v _ { y } ) of stars near the Galactic center massive black hole to identify populations with high orbital eccentricities .
It is most useful for stars with large orbital periods for which dynamical accelerations are difficult to determine .

We apply this statistic to a data set of B-stars with projected radii 0.1 \hbox { $ { } ^ { \prime \prime } $ } < p < 25 \hbox { $ { } ^ { \prime \prime } $ } ( \sim 0.004 - 1 \mathrm { pc } ) from the massive black hole in the Galactic center .
We compare the results with those from N -body simulations to distinguish between scenarios for their formation .
We find that the scenarios favored by the data correlate strongly with particular K -magnitude intervals , corresponding to different zero-age main-sequence ( MS ) masses and lifetimes .
Stars with 14 \lesssim m _ { K } \lesssim 15 ( 15 - 20 M _ { \odot } , t _ { MS } = 8 - 13 { Myr } ) match well to a disk formation origin , while those with m _ { K } \geq 15 ( < 15 M _ { \odot } , t _ { MS } > 13 { Myr } ) , if isotropically distributed , form a population that is more eccentric than thermal , which suggests a Hills binary-disruption origin .