Dying Stars May Kick Themselves Through Space

Topic: Space

A new model suggests that dying stars like our Sun may experience thousands of small kicks before becoming white dwarfs. The kicks could be caused by uneven bursts of material escaping from the star's surface. Astronomers think this process might explain why some binary star systems break apart.

When stars similar to our Sun grow old, they expand into red giants. Their outer layers churn and drift into space while their dense cores shrink into white dwarfs. A new model by Jim Fuller, a theoretical astrophysicist at Caltech, suggests that this transformation may not be as orderly as it seems.

Fuller's calculations indicate that uneven bursts of escaping material can repeatedly push a dying star in different directions, giving it thousands of small kicks before the white dwarf fully forms. These kicks are caused by blobs of matter being chaotically ejected from the surface of the bloated stars in an asymmetric fashion.

According to Fuller's model, a star approaching the white dwarf stage may experience roughly 10,000 small kicks over several hundred thousand years. Each individual push would move the star at only a few meters per second. This is equivalent to a slow jogging pace for humans.

Although the escaping material is launched in random directions, the kicks do not cancel out perfectly. Over time, they produce an overall shift in one direction through a mathematical process known as a random walk. Fuller's model suggests that the combined kicks could leave a dying star moving in a random direction at about 1 kilometer per second.

Why It Matters

This discovery can help us better understand how binary star systems form and evolve. It may also explain why some stars are found moving at high speeds through space, which could be important for understanding the formation of galaxies.

Key Facts

• Dying stars like our Sun may experience thousands of small kicks before becoming white dwarfs.
• The kicks are caused by uneven bursts of material escaping from the star's surface.
• Fuller's model suggests that a star approaching the white dwarf stage may experience roughly 10,000 small kicks over several hundred thousand years.
• Each individual push would move the star at only a few meters per second.
• The combined kicks could leave a dying star moving in a random direction at about 1 kilometer per second.

Key Terms

White Dwarf

A small, hot star that is left behind after a larger star has exhausted its fuel and expanded into a red giant.

Red Giant

A large, cool star that is in the final stages of its life cycle.

Implications

This discovery can help us better understand how binary star systems form and evolve. It may also explain why some stars are found moving at high speeds through space, which could be important for understanding the formation of galaxies.