How long can a red giant typically exist before becoming a white dwarf?

A red giant typically spends a significant period of its life cycle expanding and fusing helium in its core. This phase follows the earlier stages of stellar evolution after a star has exhausted its hydrogen fuel and transitioned off the main sequence. The time a red giant remains in that phase before shedding its outer layers to leave behind a white dwarf can range broadly, but it generally lasts around 5 billion years.

This time frame is representative of stars with masses similar to our Sun. After the red giant phase, the core collapses, and the outer layers are expelled, often creating a planetary nebula. The remnant core becomes a white dwarf, which will then gradually cool and fade over billions of years.

Considering the life cycle of such stars, other time frames like 500 million years, 1 billion years, or 10 billion years would not accurately reflect the typical duration of the red giant phase leading to the formation of a white dwarf. The processes involved in stellar evolution, such as the burning of helium and the structural changes that occur during this time, underscore why around 5 billion years is a well-supported estimate for this phase of stellar life.