NGC 150.---SBb: Strong bar. Two-arm grand-design spiral. Asymmetric
arms that start before the intersection point with the bar. Regions of
strong star formation in the areas near the arm-bar contacts. SE arm
bifurcates just beyond the bar contact point. NW arm is more linear
than the SE arm.
Aug 11/12, 1980
103aO + GG385
The spiral pattern in NGC 150 is of the
grand design type although there are three
high-surface-brightness arms rather than only two in
the reflection symmetry of grand design patterns.
Two bright inner arms start from the center.
After half a revolution one of these (called here
the first) nearly overlaps the second which,
however, can only be traced for less than half a
revolution; consequently it does not overlap the
first. The third arm crosses the first (out of the
fundamental plane?) after the first has made only
a quarter revolution outward. The third then
decreases in surface brightness and continues
outward as a very-low-luminosity arm which can
be traced for another half revolution. A
prominent dust lane threads the middle of the
first arm. Such a three-armed pattern is unusual
but not unknown.
The redshift is v_o = 1620 km/s.
On plate edge.
Very brightly overexposed in the center, possible (r'). Faint smooth outer arms.
(r'): 0.9 x 0.55.
Photometry: (I.R. 1-3.5 micron)
M.N.R.A.S., 164, 155, 1973.
= NGC 0150
main body 1.9 x 1.1
with very massive asymmetric arms; one arm appears split;
very diffuse outer disk
Extremely small, very bright nucleus
in a weak bar:
0.5 arcmin x 0.17 arcmin.
1.7 arcmin x 0.6 arcmin.
Very faint outer arms.