We report on the discovery of a new Milky Way companion stellar system located at ( \alpha _ { J 2000 } , \delta _ { J 2000 } ) = ( 22 ^ { h } 10 ^ { m } 43.15 ^ { s } , 14 ^ { \circ } 56 \arcmin 58. % 8 \arcsec ) .
The discovery was made using the eighth data release of SDSS after applying an automated method to search for overdensities in the Baryon Oscillation Spectroscopic Survey footprint .
Follow-up observations were performed using CFHT/MegaCam , which reveal that this system is comprised of an old stellar population , located at a distance of 31.9 ^ { +1.0 } _ { -1.6 } kpc , with a half-light radius of r _ { h } = 7.24 ^ { +1.94 } _ { -1.29 } pc and a concentration parameter of c = \log _ { 10 } ( r _ { t } / r _ { c } ) = 1.55 .
A systematic isochrone fit to its color-magnitude diagram resulted in \log ( age / yr ) = 10.07 ^ { +0.05 } _ { -0.03 } and [ Fe / H ] = -1.58 ^ { +0.08 } _ { -0.13 } .
These quantities are typical of globular clusters in the MW halo .
The newly found object is of low stellar mass , whose observed excess relative to the background is caused by 95 \pm 6 stars .
The direct integration of its background decontaminated luminosity function leads to an absolute magnitude of M _ { V } = -1.21 \pm 0.66 .
The resulting surface brightness is \mu _ { V } = 25.90 mag/arcsec ^ { 2 } .
Its position in the M _ { V } vs . r _ { h } diagram lies close to AM4 and Koposov 1 , which are identified as star clusters .
The object is most likely a very faint star cluster — one of the faintest and lowest mass systems yet identified .