NGC 7743 - (R)SAB(s)a

NGC 7743

De Vaucouleurs Atlas Type: (R)SAB(s)a

Filter: B

Telescope: NOT 2.5-m
North up , East left
Field Dimensions: 5.1 x 5.1 arcminutes

RC3 Type: (R)SB(s)0+
RSA Type: SBa
Surface Brightness Range Displayed: 17.5-27.5 mag per square arcsec
Absolute Blue Magnitude: -19.4

De Vaucouleurs Atlas Description:

This unusual object has several remarkable features. By itself, the bright inner zone is type SAB(s)a. The apparent bar is a weak oval crossing the area between the two main spiral arms, which is why we have adopted a family of SAB. However, attached to this zone are two conspicuous, very diffuse ``knobs", which are like handles on the bright spiral. These knobs (see also Erwin and Sparke 2003) lie near the projected minor axis of a very faint, barely distinguishable outer ring (inset). In early photographs of this object, only the bright inner zone was detected (e.g., Sandage 1961), which de Vaucouleurs classified as late S0. The B-V color index map shows that the southern ``knob" has conspicuous color contrast and may be a dwarf companion galaxy. This map also shows subtle dust features in the spiral region (central colors are not reliable).