Barred spiral

Definition

A barred spiral is a type of galaxy characterized by a central bar-shaped structure made up of stars, which extends outward to spiral arms. This distinctive shape differentiates barred spirals from regular spiral galaxies, often leading to different star formation rates and patterns. The presence of the bar can influence the dynamics of stars and gas within the galaxy, affecting the overall structure and evolution of the galaxy.

5 Must Know Facts For Your Next Test

1. Barred spiral galaxies are often classified as type SB in the Hubble sequence, while regular spiral galaxies are classified as type S.
2. Examples of well-known barred spiral galaxies include the Milky Way and NGC 1300, which both exhibit prominent bar structures.
3. The bar structure in barred spiral galaxies can help funnel gas toward the center, leading to increased star formation activity in that region.
4. Barred spirals are generally more common than regular spirals, with studies suggesting that about two-thirds of spiral galaxies have a bar.
5. The dynamics and interactions of stars in a barred spiral galaxy can be complex, often resulting in distinctive patterns of rotation and star distribution.

Review Questions

• How do barred spiral galaxies differ from regular spiral galaxies in terms of structure and star formation?
  • Barred spiral galaxies differ from regular spiral galaxies primarily in their structural features; they have a central bar-shaped structure that influences the distribution of stars and gas. This bar can funnel material toward the galaxy's center, often resulting in higher rates of star formation compared to regular spirals. Additionally, the presence of the bar changes the dynamics within the galaxy, creating unique rotational patterns and star distributions.
• Discuss the significance of the Hubble sequence in classifying barred spiral galaxies and its impact on our understanding of galaxy evolution.
  • The Hubble sequence provides a systematic way to classify galaxies based on their morphological characteristics, including barred spirals. By categorizing barred spirals as type SB, this classification helps astronomers understand their distinct properties compared to other types like regular spirals. This classification also aids in studying galaxy evolution by allowing researchers to examine how different structures may relate to factors such as star formation rates and interactions with other galaxies.
• Evaluate how the presence of a bar structure in barred spiral galaxies influences both their internal dynamics and overall evolution compared to other galaxy types.
  • The presence of a bar structure significantly influences both the internal dynamics and overall evolution of barred spiral galaxies. The bar acts as a gravitational force that redistributes stars and gas within the galaxy, enhancing star formation rates near the center. This redistribution can lead to unique patterns of stellar orbits that differ from those observed in non-barred systems. Consequently, barred spirals may evolve differently over time, experiencing varied interactions with their environment compared to other galaxy types like elliptical or regular spiral galaxies.

Related terms

spiral galaxy:

A type of galaxy that has a flat, rotating disk containing stars, gas, and dust, along with a central concentration of stars known as a bulge.

Hubble sequence: A morphological classification scheme for galaxies developed by Edwin Hubble, which categorizes galaxies into different types based on their shapes and structures.

star formation: The process by which dense regions within molecular clouds in galaxies collapse under gravity to form new stars.