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Representative lifetimes of stars as a function of their masses The change in size with time of a Sun-like star Artist's depiction of the life cycle of a Sun-like star, starting as a main-sequence star at lower left then expanding through the subgiant and giant phases, until its outer envelope is expelled to form a planetary nebula at upper right Chart of stellar evolution
The first generation of stars, known as Population III stars, formed within a few hundred million years after the Big Bang. [62] These stars were the first source of visible light in the universe after recombination. Structures may have begun to emerge from around 150 million years, and early galaxies emerged from around 180 to 700 million years.
The age of the oldest known stars approaches the age of the universe, about 13.8 billion years. Some of these are among the first stars from reionization (the stellar dawn), ending the Dark Ages about 370,000 years after the Big Bang. [1] This list includes stars older than 12 billion years, or about 87% of the age of the universe.
The most massive to explode would be just below the Chandrasekhar limit at around 1.41 solar masses and would take of the order of 10 1100 years, while the least massive to explode would be about 1.16 solar masses and would take of the order 10 32 000 years, totaling around 1% of all black dwarfs.
5th century BC – Democritus proposes that the bright band in the night sky known as the Milky Way might consist of stars. 4th century BC – Aristotle believes the Milky Way to be caused by "the ignition of the fiery exhalation of some stars which were large, numerous and close together" and that the "ignition takes place in the upper part of the atmosphere, in the region of the world which ...
The Stelliferous Era, is defined as, "6 < n < 14". This is the current era, in which matter is arranged in the form of stars, galaxies, and galaxy clusters, and most energy is produced in stars. Stars will be the most dominant objects of the universe in this era. Massive stars use up their fuel very rapidly, in as little as a few million years.
Due to the uncertainty in the value, this age for the star does not conflict with the age of the universe, determined by the Planck satellite as 13.799 ± 0.021). [127] [128] The more massive the star, the shorter its lifespan, primarily because massive stars have greater pressure on their cores, causing them to burn hydrogen more rapidly.
HD 189733 b forms around parent star HD 189733: the first planet to reveal the climate, organic constituencies, even colour (blue) of its atmosphere; 13.345 billion years (455 Mya): Vega, the fifth-brightest star in Earth's galactic neighbourhood, forms. 13.6–13.5 billion years (300-200 Mya): Sirius, the brightest star in the Earth's sky, forms.