Knowra Flocculent spiral galaxy Flocculent spiral galaxy A spiral galaxy whose arms appear as patchy, fragmented segments rather than continuous, well-defined patterns. Its irregular arm structure contrasts with the organized patterns of grand-design spirals.
Differential rotation : Rotation in which different parts of a system orbit at different angular speeds. It shears gas clouds and young stellar structures into short, irregular arm segments.
Grand-design spiral galaxy : A spiral galaxy with two or a few prominent, coherent arms extending across much of its disk. Its continuous arms provide the clearest morphological counterpart to flocculent structure.
NGC 2841 : A nearby spiral galaxy in Ursa Major known for its tightly wound, patchy spiral structure. Its arm fragments make it a well-known example of flocculent morphology.
Galaxy morphology : The study and classification of galaxies by their observable shapes and structures. Flocculent spirals are defined by morphology rather than a unique formation mechanism.
Swing amplification : A process that can amplify spiral density disturbances as differential rotation shears them through a disk. It offers a mechanism for producing transient, fragmented spiral features.
Gravitational instability : The growth of density variations when gravity overcomes pressure or other stabilizing forces. Local instabilities can gather gas into star-forming patches without a galaxy-wide spiral pattern.
Multi-armed spiral galaxy : A spiral galaxy with several prominent arms, often less dominant than the main arms of a grand-design system. Its organized multiple arms differ from the fragmented segments defining flocculent galaxies.
NGC 4414 : A nearby spiral galaxy in Coma Berenices with an irregular, patchy spiral pattern. Its visible arm segments illustrate the fragmented appearance associated with this class.
Spiral arm : An elongated, curved structure in a disk galaxy, often traced by gas, dust, and young stars. The broken appearance of these structures is the defining feature of flocculent spirals.
Stellar feedback : The return of energy and matter from stars to their surrounding interstellar gas. Feedback may disperse star-forming regions and alter the persistence of visible arm segments.
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