THE CORE OF THE NEARBY SO GALAXY NGC-7457 IMAGED WITH THE HST PLANETARY CAMERA

We have observed the nearby S0 galaxy NGC 7457 with the Planetary Camera of the Hubble Space Telescope. Spatial structure is observable at the diffraction-limited resolution of the 2.4 m HST primary despite the effects of spherical aberration. The central distribution of starlight appears consistent with a gamma almost-equal-to -1.0 power law for r < 600 pc, plus a possible additional stellar nucleus with L approximately 1 x 10(7) L. (V band). We find no evidence of a core to limits r(c) < 0.052" = 3.4 pc (H0 = 80 km s-1 Mpc-1), in contrast to a priori estimates of r(c) almost-equal-to 30 pc based on total galaxy luminosity. The center of NGC 7457 remains unresolved at HST resolution and has a central luminosity density rho-0 > 3 x 10(4) L. pc-3 (V band). This is now the second densest core known after M32. From the ground, NGC 7457 resembles any number of unresolved elliptical galaxies, which suggests that compact dense cores may be common. The images of NGC 7457 demonstrate that HST can still provide unique and astrophysically interesting information on the central structure of galaxies.