What is a blue supergiant?

A blue supergiant is a very massive, very hot and extremely luminous star, usually of spectral class O or B and luminosity class I. Examples include Rigel and Deneb.

Why do massive stars live such short lives?

Luminosity rises much faster than mass — roughly as the cube of mass or steeper. A star 20 times the Sun's mass has only 20 times the fuel but consumes it tens of thousands of times faster, so it lasts a few million years instead of ten billion.

What happens to a blue supergiant at the end?

It collapses and explodes as a core-collapse supernova, leaving behind a neutron star or, for the heaviest progenitors, a stellar-mass black hole. Supernova 1987A came from a blue supergiant.

What is a stellar wind?

It is a continuous outflow of material driven off a star's surface. In blue supergiants, radiation pressure on the outer layers accelerates the wind to thousands of kilometres per second, so the star can shed a substantial fraction of its mass before it dies.

Blue Supergiant क्या है?

A blue supergiant is a massive, ferociously hot star — typically 10 to 100 times the Sun's mass and tens of thousands of degrees at the surface. They are the brightest stars in any galaxy and the most short-lived, spending only a few million years before detonating as supernovae.

Luminosity climbs steeply with mass: roughly as mass cubed or faster. A star 20 times heavier than the Sun therefore does not shine 20 times brighter but tens of thousands of times brighter, and it must burn through its fuel at a matching rate. That is the bargain massive stars make. They are born, blaze across a galaxy, and are gone inside the span of a mountain range.

At these temperatures the light itself becomes a force. Radiation pressure on the outer layers drives a stellar wind moving at thousands of kilometres per second, stripping away a Sun's worth of mass over the star's lifetime and hollowing out a bubble in the surrounding interstellar gas. The most extreme cases shed their hydrogen envelopes entirely and become Wolf-Rayet stars, bare fusing cores exposed to space.

Their endings write much of the periodic table. When the core finally builds up iron, fusion can no longer release energy, the core collapses in under a second and the star explodes — leaving a neutron star or a black hole and seeding the galaxy with heavy elements. Rigel in Orion and Deneb in Cygnus are blue supergiants; both are far brighter, and far younger, than anything else in their neighbourhood.