De Vaucouleurs Atlas Type: (R1')SB(s)ab
Telescope: CTIO 1.5-m
North left , East down
Field Dimensions: 4.6 x 3.4 arcminutes
RC3 Type: (R')SB(s)ab
RSA Type: SBb(s)I-II
Surface Brightness Range Displayed: 16.0-26.0 mag per square arcsec
Absolute Blue Magnitude: -20.4
De Vaucouleurs Atlas Description:
This nearly face-on object is mostly defined by a complex, dusty bar. There is no clear inner ring or pseudoring, hence the (s) classification. The outer arms form an (R1' ) outer pseudoring . The Sab classification is based on the smoothness of the outer arms, and the dustiness of the bar.
NGC 7552 is best known for its central starburst , which is associated with a small nuclear ring (Forbes et al. 1994) that does not stand out as ringlike in the B-band image. The dusty bar morphology is very unusual. As a member of the Grus triplet, the galaxy may be affected by an interaction that has disturbed its morphology.
Hameed and Devereux (1999) show an intriguing H-alpha image of NGC 7552 . The bar is prominent, and numerous HII regions are scattered within the disk in an asymmetric way.