Hubble Atlas, p. 4
March 7/8, 1948
NGC 4684 is a normal S0_1_(7) with a three-zone luminosity
structure. However, the intermediate zone is an internal luminous ring
surrounding a small, central region similar to those of NGC 148, NGC
1175, NGC 1461, NGC 1527, and NGC 2549 (all on panel 40 in this S0
section). The extensive outer envelope, the last of the three zones,
insures the S0 classification.
The galaxy is shown here among the S0_1/2_ subtypes because it is
early in having a dust lane or a separation of material which, in this
case, is the luminous ring in the inner disk. The feature is similar
to, but earlier than, that in the real S0_2/3_ subtypes in NGC 2310
(S0_2/3_) and NGC 7332 (S0_2/3_) on this page.
NGC 4684: This is a strongly inclined and disk dominated S0. The bar
implied by the RC2 classification was not detected.
Very bright, extremely foreshortened nucleus and bar on minor axis. (r):
0.25 arcmin x 0.06 arcmin. Lens: 0.4 arcmin x 0.1 arcmin. Almost edge-on.
Lund 9 dimensions are for the bright part only.
Mar. 7/8, 1948
This and NGC 3329 are good type examples of S01 galaxies.
The three characteristic zones of different luminosity are