Which will die first, Vega, Altair, or the Sun?

Among the three stars — Vega, Altair, and the Sun — Vega will die first, followed by Altair, and then our Sun, which will be the last to reach the end of its life.

The primary reason for this sequence lies in their masses and lifespans, which are inversely related: the more massive a star, the faster it burns through its nuclear fuel and the shorter its lifespan.

Stellar Mass and Lifespan: The Trade-Off

To understand this better, let’s compare their masses and expected main-sequence lifespans:

• Vega, the brightest star in the constellation Lyra, is more than twice as massive as the Sun. It is a relatively young star, around 450 million years old, and is already about halfway through its main-sequence life. At this pace, it’s expected to exhaust its core hydrogen in less than 500 million years from now.
• Altair, the brightest star in Aquila, is slightly less massive than Vega and rotates very rapidly. Its mass gives it a longer lifespan than Vega—about 1 to 2 billion years in total.
• The Sun, our middle-aged yellow dwarf, has an estimated total lifespan of about 10 billion years. Currently, it is about 4.6 billion years old, with roughly 5 billion years remaining before it leaves the main sequence.

Why Bigger Stars Die Sooner

Massive stars have stronger gravitational pressure at their cores, which leads to higher temperatures and faster nuclear fusion. Although they have more fuel to burn, they burn it much more rapidly, dramatically shortening their lifespans.

In contrast, stars like the Sun burn fuel more slowly and steadily, giving them far longer to shine.

Conclusion

Vega will die first, likely within a few hundred million years. Altair will follow, and the Sun will live the longest of the three. Their fates serve as a reminder of the delicate balance between mass, energy, and time in stellar evolution.