What is the longest, most stable phase of stellar life represented on the H-R diagram?

Answer

The Main Sequence

A star spends roughly 90% of its active existence in the stable hydrogen-burning phase on the Main Sequence.

What is the longest, most stable phase of stellar life represented on the H-R diagram?

#Videos

HR Diagram Explained - Star Color, Temperature and Luminosity

temperaturesequencestarLuminositydiagram