Starburst galaxies

Definition

Starburst galaxies are a class of galaxies that are experiencing an exceptionally high rate of star formation, often resulting in the creation of new stars at a rate significantly greater than that of typical galaxies. This intense activity often leads to bright emissions across various wavelengths, making them crucial for understanding stellar evolution and the thermodynamic processes involved in star formation.

5 Must Know Facts For Your Next Test

1. Starburst galaxies can form new stars at rates that exceed 100 solar masses per year, compared to typical galaxies which form about 1-10 solar masses per year.
2. These galaxies are often characterized by their bright infrared emissions, as dust heated by newly formed stars re-radiates energy in the infrared spectrum.
3. Starbursts can be triggered by interactions or mergers with other galaxies, leading to increased gas inflow and compression which fuels star formation.
4. The lifespan of a starburst phase typically lasts for tens of millions to a few hundred million years, making it a relatively short but intense period in a galaxy's life.
5. Starburst galaxies are thought to evolve into quiescent elliptical galaxies after exhausting their gas reserves, indicating a significant change in their star formation activity over time.

Review Questions

• How do the conditions in starburst galaxies differ from those in typical galaxies, and what implications does this have for understanding thermodynamic processes?
  • Starburst galaxies have much higher densities of gas and dust, along with intense radiation from newly formed stars. This leads to elevated temperatures and pressures within these regions, which significantly affects thermodynamic processes such as heat transfer and energy generation. Understanding these conditions helps astronomers learn more about how star formation occurs under extreme environments and the subsequent evolution of the galaxy.
• Discuss the impact of galaxy interactions on the star formation rates observed in starburst galaxies.
  • Galaxy interactions, such as mergers or close encounters, often compress gas clouds and trigger shock waves that enhance star formation rates. This results in bursts of activity where massive amounts of stars are formed rapidly. Such interactions can lead to significant changes in the structure and dynamics of both galaxies involved, influencing their future evolution and star formation patterns.
• Evaluate the role of thermodynamics in explaining the lifecycle of starburst galaxies and their eventual transformation into other types of galaxies.
  • Thermodynamics plays a key role in understanding how energy flows within starburst galaxies during their intense star formation phase. As stars form rapidly, they generate heat and increase the internal pressure of surrounding gas. Eventually, as these stars exhaust their nuclear fuel and supernovae occur, much of this energy is released back into the interstellar medium, heating it up and potentially driving away remaining gas. This process influences the lifecycle of the galaxy, leading to a decline in star formation and a potential transformation into a quiescent galaxy or even an elliptical galaxy over billions of years.

Related terms

Star Formation Rate (SFR): A measure of the mass of stars formed per unit time, often expressed in solar masses per year, which is particularly high in starburst galaxies.

Active Galactic Nuclei (AGN): The extremely bright center of some galaxies, powered by supermassive black holes, which can influence star formation in the surrounding regions.

H II Regions: Clouds of gas ionized by the radiation from young, hot stars; these regions are often found in starburst galaxies and are indicators of ongoing star formation.