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In astrophysics, mass transfer is the process by which matter gravitationally bound to a body, usually a star, fills its Roche lobe and becomes gravitationally bound to a second body, usually a compact object (white dwarf, neutron star or black hole), and is eventually accreted onto it.
In astrophysics, accretion is the accumulation of particles into a massive object by gravitationally attracting more matter, typically gaseous matter, into an accretion disk. [ 1 ] [ 2 ] Most astronomical objects , such as galaxies , stars , and planets , are formed by accretion processes.
The layers of the Earth, a differentiated planetary body. In planetary science, planetary differentiation is the process by which the chemical elements of a planetary body accumulate in different areas of that body, due to their physical or chemical behavior (e.g. density and chemical affinities).
Pebble accretion is the accumulation of particles, ranging from centimeters up to meters in diameter, into planetesimals in a protoplanetary disk that is enhanced by aerodynamic drag from the gas present in the disk. This drag reduces the relative velocity of pebbles as they pass by larger bodies, preventing some from escaping the body's gravity.
The most prominent accretion disks are those of active galactic nuclei and of quasars, which are thought to be massive black holes at the center of galaxies. As matter enters the accretion disc, it follows a trajectory called a tendex line, which describes an inward spiral. This is because particles rub and bounce against each other in a ...
Meteorites are often studied as part of cosmochemistry. Cosmochemistry (from Ancient Greek κόσμος (kósmos) 'universe' and χημεία (khēmeía) 'chemistry') or chemical cosmology is the study of the chemical composition of matter in the universe and the processes that led to those compositions. [1]
The runaway accretion lasts between 10,000 and 100,000 years and ends when the largest bodies exceed approximately 1,000 km in diameter. [20] Slowing of the accretion is caused by gravitational perturbations by large bodies on the remaining planetesimals. [20] [65] In addition, the influence of larger bodies stops further growth of smaller ...
Of these, perhaps the most prominent is the theory of competitive accretion, which suggests that massive protostars are "seeded" by low-mass protostars which compete with other protostars to draw in matter from the entire parent molecular cloud, instead of simply from a small local region. [63] [64]