Red Supergiant
A late stage in stellar evolution, formed when a star with a mass greater than about 8 solar masses expands after exhausting the hydrogen in its core. Its outer layers expand and cool extremely due to radiation pressure, giving it a red color, and its radius can reach hundreds to over a thousand times the solar radius.
Timeline (last 90 days)
The star type with the largest radius in the known universe is the red supergiant, whose radius can reach about two thousand times that of the Sun, close to nine astronomical units; if placed at the Sun's position, its surface would engulf everything from Mercury to Jupiter and almost reach Saturn's orbit.
Stars with masses exceeding about 8 times the mass of the Sun evolve further into red supergiants after exhausting the hydrogen fuel in their cores.
Red supergiants have surface temperatures of about 3500–4500K, luminosities reaching hundreds of thousands of times that of the Sun, lifetimes of only a few million years, and typically end in a supernova explosion.
The stellar winds of red supergiants are extremely powerful, with mass loss rates reaching one millionth of a solar mass per year or even higher.
The outer atmospheres of red supergiants are extremely tenuous and dynamically changing, and stellar pulsation, convection, and mass ejection make it impossible to clearly define a boundary between the stellar surface and the stellar wind, so there is no precise upper limit on the maximum radius.
The outer material of red supergiants is ejected and becomes part of the interstellar medium, and this material is rich in elements such as carbon, oxygen, and silicon, serving as the raw material for the next generation of stars and planets, and part of the heavy elements in Earth's life comes from this.
All Facts (6)
The star type with the largest radius in the known universe is the red supergiant, whose radius can reach about two thousand times that of the Sun, close to nine astronomical units; if placed at the Sun's position, its surface would engulf everything from Mercury to Jupiter and almost reach Saturn's orbit.
50%UnverifiedStars with masses exceeding about 8 times the mass of the Sun evolve further into red supergiants after exhausting the hydrogen fuel in their cores.
50%UnverifiedRed supergiants have surface temperatures of about 3500–4500K, luminosities reaching hundreds of thousands of times that of the Sun, lifetimes of only a few million years, and typically end in a supernova explosion.
50%UnverifiedThe stellar winds of red supergiants are extremely powerful, with mass loss rates reaching one millionth of a solar mass per year or even higher.
50%UnverifiedThe outer atmospheres of red supergiants are extremely tenuous and dynamically changing, and stellar pulsation, convection, and mass ejection make it impossible to clearly define a boundary between the stellar surface and the stellar wind, so there is no precise upper limit on the maximum radius.
50%UnverifiedThe outer material of red supergiants is ejected and becomes part of the interstellar medium, and this material is rich in elements such as carbon, oxygen, and silicon, serving as the raw material for the next generation of stars and planets, and part of the heavy elements in Earth's life comes from this.
50%