Search results
Results From The WOW.Com Content Network
The W51 nebula in Aquila - one of the largest star factories in the Milky Way (August 25, 2020). Star formation is the process by which dense regions within molecular clouds in interstellar space, sometimes referred to as "stellar nurseries" or "star-forming regions", collapse and form stars. [1]
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
Later in its life, a low-mass star will slowly eject its atmosphere via stellar wind, forming a planetary nebula, while a higher–mass star will eject mass via a sudden catastrophic event called a supernova. The term supernova nucleosynthesis is used to describe the creation of elements during the explosion of a massive star or white dwarf.
The Kelvin–Helmholtz mechanism is an astronomical process that occurs when the surface of a star or a planet cools. The cooling causes the internal pressure to drop, and the star or planet shrinks as a result. This compression, in turn, heats the core of the star/planet.
Star formation has been occurring continuously in galaxies since that time. The primordial nuclides were created by Big Bang nucleosynthesis, stellar nucleosynthesis, supernova nucleosynthesis, and by nucleosynthesis in exotic events such as neutron star collisions.
Observations suggest that star formation efficiency in molecular gas is almost universal, with around 1% of the gas being converted into stars per free fall time. [30] In simulations, the gas is typically converted into star particles using a probabilistic sampling scheme based on the calculated star formation rate.
Star formation; Object classes; Interstellar medium; Molecular cloud; Bok globule; Dark nebula; Young stellar object; Protostar; Pre-main-sequence star; T Tauri star; Herbig Ae/Be star; Herbig–Haro object; Theoretical concepts; Accretion; Initial mass function; Jeans instability; Kelvin–Helmholtz mechanism; Nebular hypothesis; Planetary ...
Stellar structure models describe the internal structure of a star in detail and make predictions about the luminosity, the color and the future evolution of the star. Different classes and ages of stars have different internal structures, reflecting their elemental makeup and energy transport mechanisms.