We confirm the reality of the recently discovered Milky Way stellar cluster Gaia 1 using spectra acquired with the HERMES and AAOmega spectrographs of the Anglo-Australian Telescope .
This cluster had been previously undiscovered due to its close angular proximity to Sirius , the brightest star in the sky at visual wavelengths .
Our observations identified 41 cluster members , and yielded an overall metallicity of [ \textrm { Fe } / \textrm { H } ] = -0.13 \pm 0.13 and barycentric radial velocity of v _ { r } = 58.30 \pm 0.22 km/s .
These kinematics provide a dynamical mass estimate of 12.9 ^ { +4.6 } _ { -3.9 } \times 10 ^ { 3 } M _ { \sun } .
Isochrone fits to Gaia , 2MASS , and Pan-STARRS1 photometry indicate that Gaia 1 is an intermediate age ( \sim 3 Gyr ) stellar cluster .
Combining the spatial and kinematic data we calculate Gaia 1 has a circular orbit with a radius of about 12 kpc , but with a large out of plane motion : z _ { \textrm { max } } = 1.1 ^ { +0.4 } _ { -0.3 } kpc .
Clusters with such orbits are unlikely to survive long due to the number of plane passages they would experience .