Herbig-Haro (HH) object

Definition

Herbig-Haro (HH) objects are small patches of nebulosity associated with newly born stars. They form when jets of ionized gas ejected by young stars collide with nearby clouds of gas and dust.

5 Must Know Facts For Your Next Test

1. HH objects are often found in star-forming regions within molecular clouds.
2. They are named after astronomers George Herbig and Guillermo Haro, who independently discovered them in the 1950s.
3. These objects are typically observed in visible wavelengths due to their emission lines from ionized gases.
4. The interaction between the jet and the surrounding material creates shock waves that heat the gas, causing it to glow.
5. HH objects can change over relatively short astronomical timescales, making them useful for studying early stellar evolution.

Review Questions

• What causes the formation of Herbig-Haro objects?
• Why are HH objects important for studying star formation?
• How do Herbig-Haro objects produce visible light?

Related terms

Protostar: A very young star still in the process of forming that has not yet reached the main sequence.

Molecular Cloud: A cold and dense region of space where new stars are born, primarily composed of molecular hydrogen.

Stellar Jets: Narrow beams of matter ejected at high speeds from newly formed stars, often associated with HH objects.