De Vaucouleurs Atlas Type: (R)SAB(s)a
Telescope: CTIO 1.5-m
North up , East left
Field Dimensions: 3.6 x 3.6 arcminutes
RC3 Type: (R)SAB(s)0/a
RSA Type: RSb(s)II
Surface Brightness Range Displayed: 17.0-26.0 mag per square arcsec
Absolute Blue Magnitude: -19.5
De Vaucouleurs Atlas Description:
This complex object is a very early-type example of an NGC 5248 -type spiral, where a broad oval zone includes a bright, open spiral. The appearance has led to conflicting classifications for the object. While de Vaucouleurs classifies NGC 4457 as type S0/a, Sandage classifies it as type Sb. Except for the appearance of the inner spiral, the galaxy very much looks like an early type. We adopt type Sa as a compromise between the type implied by the spiral and the type implied by the outer disk. The spiral is defined mainly by two fairly open arms, which is typical of the NGC 5248 types. These arms are the basis for the (s) classification. The reason for the SAB classification is the strong, broad oval these arms are distributed within. The outer ring is a very well-defined feature that is completely detached.
NGC 4457 is a member of the Virgo Cluster . Like NGC 4580 , NGC 4457 is classified as T/N[s] by Koopmann and Kenney (2004), meaning it has a severely truncated star-forming disk having a normalized massive star formation rate in its inner regions that is comparable to that of other galaxies in a Virgo Cluster sample. Thus, its morphology has been affected by its environment .