How long do massive stars last

For main sequence stars, the energy comes from hydrogen fusion and we have:. The mass converted into energy through burning will be a fraction f of the total mass of the star. Combining the last two equations, we have the following expression for the main sequence lifetime:. Note: this expression is an approximation only, and not valid for very massive or very light stars.

On the other hand, the least massive stars that we know are so parsimonious in their fuel consumption that they can live to ages older than that of the universe itself--about 15 billion years. But because they have such low energy output, they are very faint. When we look up at the stars at night, almost all of the ones we can see are intrinsically more massive and brighter than our sun.

Most longer-lasting stars that are fainter than the sun are just too dim to view without telescopic aid. At the end of a stars life, when the supply of available hydrogen is nearly exhausted, it swells up and brightens. Many stars that are visible to the naked eye are in this stage of their life cycles because this bias brings them preferentially to our attention.

They are, on average, a few hundred million years old and slowly coming to the end of their lives. A massive star such as the red Betelgeuse in Orion, in contrast, approaches its demise much more quickly. It has been spending its fuel so extravagantly that it cannot be older than about 10 million years.

Within a million years, it is expected to go into complete collapse before probably exploding as a supernova.

Stars are still being born at the present time from dense clouds of dust and gas, but they remain deeply embedded in their placental material and cannot be seen in visible light. The enveloping dust is transparent to infrared radiation, however, so scientists using modern detecting devices can easily locate and study them.

Answering the question, "How do stars die? The most massive stars quickly exhaust their fuel supply and explode in core-collapse supernovae, some of the most energetic explosions in the universe.

The remnant stellar core will form a neutron star or a black hole, depending on how much mass remains. If the core contains between 1. Curious about black holes? As a bonus, you'll also receive our weekly e-newsletter with the latest astronomy news. Average stars with up to 1. As they run out of hydrogen to fuse in their cores, they swell into red giant stars before shedding their outer layers. The remnant left behind in these planetary nebulae is a white dwarf star.

Like neutron stars, white dwarfs no longer fuse hydrogen into helium, instead depending on degeneracy pressure for support — this time, the electrons are degenerate, packed together and forced into higher energy states, rather than the neutrons. Left to their own devices, white dwarfs will eventually fade into black dwarfs.

No black dwarfs have been observed yet because a white dwarf takes longer than the current age of the universe to fade away. And if the white dwarf is part of a binary system, it may avoid that fate altogether.