We report the discovery of an ultra-faint stellar system in the constellation of Pegasus .
This concentration of stars was detected by applying our overdensity detection algorithm to the SDSS-DR10 and confirmed with deeper photometry from the Dark Energy Camera at the 4-m Blanco telescope .
The best-fitting model isochrone indicates that this stellar system , Kim 1 , features an old ( 12 Gyr ) and metal-poor ( [ Fe/H ] \sim - 1.7 ) stellar population at a heliocentric distance of 19.8 \pm 0.9 kpc .
We measure a half-light radius of 6.9 \pm 0.6 pc using a Plummer profile .
The small physical size and the extremely low luminosity are comparable to the faintest known star clusters Segue 3 , Koposov 1 & 2 , and Muñoz 1 .
However , Kim 1 exhibits a lower star concentration and is lacking a well defined center .
It also has an unusually high ellipticity and irregular outer isophotes , which suggests that we are seeing an intermediate mass star cluster being stripped by the Galactic tidal field .
An extended search for evidence of an associated stellar stream within the 3 sqr deg DECam field remains inconclusive .
The finding of Kim 1 is consistent with current overdensity detection limits and supports the hypothesis that there are still a substantial number of extreme low luminosity star clusters undetected in the wider Milky Way halo .