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Intrinsic variable types in the Hertzsprung–Russell diagram showing the Yellow Hypergiants above (i.e. more luminous than) the Cepheid instability strip. A yellow hypergiant (YHG) is a massive star with an extended atmosphere, a spectral class from A to K, and, starting with an initial mass of about 20–60 solar masses, has lost as much as half that mass.
The list specifically excludes both white dwarfs – former stars that are now seen to be "dead" but radiating residual heat – and black holes – fragmentary remains of exploded stars which have gravitationally collapsed, even though accretion disks surrounding those black holes might generate heat or light exterior to the star's remains ...
Widely recognised as being among the largest known stars, [19] radius decreased to ~500 R ☉ during the 2020 great dimming event. [73] R Horologii: 630 [58] L/T eff: A red giant star with one of the largest ranges in brightness known of stars in the night sky visible to the unaided eye. Despite its large radius, it is less massive than the Sun.
Parts-per-million chart of the relative mass distribution of the Solar System, each cubelet denoting 2 × 10 24 kg. This article includes a list of the most massive known objects of the Solar System and partial lists of smaller objects by observed mean radius. These lists can be sorted according to an object's radius and mass and, for the most ...
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]
c. 475 BCE – Parmenides is credited to be the first Greek who declared that the Earth is spherical and is situated in the centre of the universe, believed to have been the first to detect the identity of Hesperus, the evening-star, and Phosphorus, the morning-star (Venus), [13] and by some, the first to claim that moonlight is a reflection of ...
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 most luminous yellow stars, the yellow hypergiants, are amongst the visually brightest stars, with absolute magnitudes around −9, although still less than a million L ☉. There is a strong upper limit to the luminosity of red supergiants at around half a million L ☉. Stars that would be brighter than this shed their outer layers so ...