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For stars with metallicity similar to the Sun, the theoretical minimum mass the star can have and still undergo fusion at the core, is estimated to be about 75 M J. [159] [160] When the metallicity is very low, the minimum star size seems to be about 8.3% of the solar mass, or about 87 M J.
List of the largest known stars in Andromeda and Triangulum galaxies Star name Solar radii (Sun = 1) Galaxy Method [a] Notes Theoretical limit of star size (Andromeda Galaxy) ≳1,750 [11] L/T eff: Estimated by measuring the fraction of red supergiants at higher luminosities in a large sample of stars. Assumes an effective temperature of 3,625 K.
Astronomers have long hypothesized that as a protostar grows to a size beyond 120 M ☉, something drastic must happen. [2] Although the limit can be stretched for very early Population III stars, and although the exact value is uncertain, if any stars still exist above 150–200 M ☉ they would challenge current theories of stellar evolution.
Sagittarius A*, abbreviated as Sgr A* (/ ˈ s æ dʒ ˈ eɪ s t ɑːr / SADGE-AY-star [3]), is the supermassive black hole [4] [5] [6] at the Galactic Center of the Milky Way.Viewed from Earth, it is located near the border of the constellations Sagittarius and Scorpius, about 5.6° south of the ecliptic, [7] visually close to the Butterfly Cluster (M6) and Lambda Scorpii.
Main-sequence stars vary in surface temperature from approximately 2,000 to 50,000 K, whereas more-evolved stars – in particular, newly-formed white dwarfs – can have surface temperatures above 100,000 K. [3] Physically, the classes indicate the temperature of the star's atmosphere and are normally listed from hottest to coldest.
An artist's impression of Sirius A and Sirius B, a binary star system. Sirius A, an A-type main-sequence star, is the larger of the two. An A-type main-sequence star (A V) or A dwarf star is a main-sequence (hydrogen burning) star of spectral type A and luminosity class V (five). These stars have spectra defined by strong hydrogen Balmer ...
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 A mass-radius plot ...
A giant star has a substantially larger radius and luminosity than a main-sequence (or dwarf) star of the same surface temperature. [1] They lie above the main sequence (luminosity class V in the Yerkes spectral classification) on the Hertzsprung–Russell diagram and correspond to luminosity classes II and III. [2]