Two dwarf galaxies, WOC2017-07 and PGC 704814, located in the vicinity of the nearby luminous spiral galaxy NGC 253 were observed with the Advanced Camera for Surveys on the Hubble Space Telescope. Their distances of 3.62 0.18 Mpc and 3.66 0.18 Mpc were derived using the tip of the red giant branch method. These distances are consistent with the dwarf galaxies being members of the NGC 253 group. Based on the radial velocities and projected separations of seven assumed dwarf companions, we estimated the total mass of NGC 253 to be (8.1 2.6)10¹¹ M _⊙, giving a total-mass-to-K-luminosity ratio of M _orb/L _K = (8.5 2.7)M _⊙/L _⊙. A notable property of NGC 253 is its declined rotation curve. NGC 253 joins four other luminous spiral galaxies in the Local Volume with declined rotation curves (NGC 2683, NGC 2903, NGC 3521, and NGC 5055) that together have the low average total-mass-to-luminosity ratio, M _orb/L _K = (5.5 1.1)M _⊙/L _⊙. This value is only ∼1/5 of the corresponding ratio for the Milky Way and M31.

哈勃太空望远镜上的高级巡天相机观测到了两个矮星系 WOC2017-07 和 PGC 704814，它们位于附近的发光旋涡星系 NGC 253 附近。它们的距离 3.62 0.18 Mpc 和 3.66 0.18 Mpc 是使用红巨星分支法的尖端推导出来的。这些距离与属于 NGC 253 群的矮星系一致。根据七个假定的矮伴星的径向速度和投影间隔，我们估计 NGC 253 的总质量为 (8.1 2.6)10 ¹¹ M _⊙，得出总质量与K光度比为M _orb / L _K = (8.5 2.7) M _⊙ / L _⊙ . NGC 253 的一个显着特性是它的下降旋转曲线。NGC 253 加入了本地体积中其他四个旋转曲线下降的发光螺旋星系（NGC 2683、NGC 2903、NGC 3521 和 NGC 5055），这些星系的平均总质光比M _orb / L _K较低= (5.5 1.1) M _⊙ / L _⊙。该值仅为银河系和 M31 对应比率的 1/5。