A spiral galaxy is a type of galaxy characterized by a central bulge of old Population II stars surrounded by a rotating disc of younger Population I stars. A spiral galaxy maintains its spiral …

Spiral galaxies are named by their spiral structures that extend from the center into the galactic disc. The spiral arms are sites of ongoing star formation and are brighter than the surrounding …

Spiral galaxies consist of a flattened disk, with stars forming a (usually two-armed) spiral structure, and a central concentration of stars known as the bulge, which is similar in appearance to an …

旋涡星系（Spiral Galaxy），是观测到的数量最多的一种星系，因其形状似旋涡而得名。 旋涡星系在其对称面附近含有大量的弥漫物质，从正面看，形状像旋涡；从侧面看，便呈梭状。

2018年11月19日 · Spiral galaxies are twisted collections of stars and gas that often have beautiful shapes and are made up of hot young stars. Most of the galaxies that scientists have …

Spiral galaxies are classified as Sa/SBa, Sb/SBb or Sc/SBc (classic/barred) according to the tightness of their spiral, the clumpiness of their spiral arms, and the size of their central bulge. …

2020年1月8日 · There are currently 3 classifications of classical spiral galaxies and another 3 for barred spiral galaxies: 1. Spiral galaxy type A – abbreviation Sa – they have a big central …

2024年12月1日 · Learn about spiral galaxies’ rotation, shape, size, stellar composition, arm structure, central region, and overall disk characteristics. Spiral galaxies are divided into two …

2020年1月31日 · I have learned that the notation to classify spiral galaxies in the De Vaucouleurs system goes like "SA for spirals without bar, SB for spirals with bar and SAB for intermediate …

Spiral galaxies are subdivided among three classes Sa, Sb, Sc, with a parallel sequence for Barred Spirals SBa, SBb, SBc. (More modern classifications add a class Sd and subdivide …