What two key physical features guide the differentiation between spiral subtypes (a, b, c) in the Hubble scheme?
Answer
The relative size of the central bulge versus the disk, and the prominence/winding pattern of the spiral arms
The classification of unbarred (S) and barred (SB) spirals relies on assessing two main morphological factors: how large the central bulge is compared to the disk, and how tightly the spiral arms are wound.
Related Questions
What are the three main components of a typical spiral galaxy?What two key physical features guide the differentiation between spiral subtypes (a, b, c) in the Hubble scheme?Which Hubble subtype designation is characterized by a prominent, large central bulge and spiral arms wound very tightly?What morphological characteristic defines an Sc galaxy compared to an Sa galaxy?What is the standard designation used for spiral galaxies that possess a central bar structure?What is the key structural difference between a spiral galaxy (S) and a Lenticular galaxy (S0)?What does the term 'Grand Design' refer to when describing spiral arm texture?What is the classification scheme universally accepted for categorizing spirals based on observable morphology?In terms of stellar populations, what characteristic tends to correlate with the Sa morphological type?How does the presence of a central bar structure (SB) dynamically influence the galaxy?