As of 2013, there were only two known multiple-planet systems within the bounds of Aquarius: the Gliese 876 and HD 215152 systems. The former is quite prominent; the latter has only two planets and has a host star farther away at 21.5 parsecs. The HD 215152 system consists of the planets HD 215152 b and HD 215152 c orbiting their K0-type, magnitude 8.13 sun. Both discovered in 2011 by the radial velocity method, the two tiny planets orbit very close to their host star. HD 215152 c is the larger at 0.0097 Jupiter masses (still significantly larger than the Earth, which weighs in at 0.00315 Jupiter masses); its smaller sibling is barely smaller at 0.0087 Jupiter masses. The error in the mass measurements (0.0032 and respectively) is large enough to make this discrepancy statistically insignificant. HD 215152 c also orbits further from the star than HD 215152 b, 0.0852 AU compared to 0.0652.