Stellar mass loss
Encyclopedia
Stellar mass loss is a phenomenon observed in some massive star
s. It occurs when a triggering event causes the ejection of a large portion of the star's mass. Stellar mass loss can also occur when a star gradually loses material to a binary companion or into interstellar space.
s, the tidal attraction of the gasses near the center of mass are sufficient to pull gas from one star onto its partner. This effect is especially prominent when the partner is a white dwarf
, neutron star
, or black hole
.
in the core. The final stage of a red giant's life will also result in prodigious mass loss as the star loses its outer layers to form a planetary nebula
.
Star
A star is a massive, luminous sphere of plasma held together by gravity. At the end of its lifetime, a star can also contain a proportion of degenerate matter. The nearest star to Earth is the Sun, which is the source of most of the energy on Earth...
s. It occurs when a triggering event causes the ejection of a large portion of the star's mass. Stellar mass loss can also occur when a star gradually loses material to a binary companion or into interstellar space.
Causes
A number of factors can contribute to the loss of mass in giant stars. A few are listed below:- Gravitational attraction of a binary companion
- Coronal mass ejectionCoronal mass ejectionA coronal mass ejection is a massive burst of solar wind, other light isotope plasma, and magnetic fields rising above the solar corona or being released into space....
-type events - Ascension to red giantRed giantA red giant is a luminous giant star of low or intermediate mass in a late phase of stellar evolution. The outer atmosphere is inflated and tenuous, making the radius immense and the surface temperature low, somewhere from 5,000 K and lower...
or red supergiantRed supergiantRed supergiants are supergiant stars of spectral type K or M. They are the largest stars in the universe in terms of volume, although they are not the most massive...
status
Gravitational Mass Loss
Often when a star is a member of a pair of close-orbiting binary starBinary star
A binary star is a star system consisting of two stars orbiting around their common center of mass. The brighter star is called the primary and the other is its companion star, comes, or secondary...
s, the tidal attraction of the gasses near the center of mass are sufficient to pull gas from one star onto its partner. This effect is especially prominent when the partner is a white dwarf
White dwarf
A white dwarf, also called a degenerate dwarf, is a small star composed mostly of electron-degenerate matter. They are very dense; a white dwarf's mass is comparable to that of the Sun and its volume is comparable to that of the Earth. Its faint luminosity comes from the emission of stored...
, neutron star
Neutron star
A neutron star is a type of stellar remnant that can result from the gravitational collapse of a massive star during a Type II, Type Ib or Type Ic supernova event. Such stars are composed almost entirely of neutrons, which are subatomic particles without electrical charge and with a slightly larger...
, or black hole
Black hole
A black hole is a region of spacetime from which nothing, not even light, can escape. The theory of general relativity predicts that a sufficiently compact mass will deform spacetime to form a black hole. Around a black hole there is a mathematically defined surface called an event horizon that...
.
Mass Ejection
Certain classes of stars, especially Wolf-Rayet stars are sufficiently massive and distended that their hold on their upper layers is rather weak. Often, events such as solar flares and coronal mass ejections will then be sufficiently powerful to blast some of the upper material into space.Red Giant Mass Loss
Stars which have entered the red giant phase are notorious for rapid mass loss. As above, the gravitational hold on the upper layers is weakened, and they may be shed into space by violent events such as the beginning of a helium flashHelium flash
A helium flash is the runaway fusion of helium in the core of low mass stars of less than about 2.25 solar masses and greater than about 0.5 solar mass, or on the surface of an accreting white dwarf star. They may also occur in the outer layers of larger stars in shell flashes...
in the core. The final stage of a red giant's life will also result in prodigious mass loss as the star loses its outer layers to form a planetary nebula
Planetary nebula
A planetary nebula is an emission nebula consisting of an expanding glowing shell of ionized gas ejected during the asymptotic giant branch phase of certain types of stars late in their life...
.
See also
- red giantRed giantA red giant is a luminous giant star of low or intermediate mass in a late phase of stellar evolution. The outer atmosphere is inflated and tenuous, making the radius immense and the surface temperature low, somewhere from 5,000 K and lower...
- red supergiantRed supergiantRed supergiants are supergiant stars of spectral type K or M. They are the largest stars in the universe in terms of volume, although they are not the most massive...
- coronal mass ejectionCoronal mass ejectionA coronal mass ejection is a massive burst of solar wind, other light isotope plasma, and magnetic fields rising above the solar corona or being released into space....
- helium flashHelium flashA helium flash is the runaway fusion of helium in the core of low mass stars of less than about 2.25 solar masses and greater than about 0.5 solar mass, or on the surface of an accreting white dwarf star. They may also occur in the outer layers of larger stars in shell flashes...
- second ascension