An Etymological Dictionary of Astronomy and Astrophysics
English-French-Persian

An accretion process whereby material coming from an → accretion disk settles onto the → protostellar surface through a geometrically thin layer or thin accretion columns. Heat brought into the protostar in the accretion flow radiates freely into space until the temperature attains the photospheric value. Most of the stellar surface is unaffected by the accretion flow (see, e.g., Hosokawa et al. 2010, ApJ 721, 478).

→ cold; → disk; → accretion.

The act or process of working with another or others on a joint project.

From Fr. collaboration, noun of action from L. collaborare from → com- "with" + labore "to work."

Hamkâri, from ham-, → com-, + kâr, → work, + -i verbal noun suffix.

The idea, central to the → Copenhagen Interpretation of quantum theory, whereby at the moment of observation the → wave function changes irreversibly from a description of all of the possibilities that could be observed to a description of only the event that is observed. More specifically, quantum entities such as electrons exist as waves until they are observed, then "collapse" into point-like particles. According to the Copenhagen Interpretation, observation causes the wave function to collapse. However it is not known what causes the wave function to collapse. Same as → wave collapse.

→ collapse; → wave function.

1) The act or process of collecting.
2) A group of objects or works to be seen, studied, or kept together.

Verbal noun from → collect.

Formation of stars, especially → massive stars, in group as opposed to individual formation.

→ collective; → star; → formation.

The process of forming collectives or collective communities where property and resources are owned by the community and not individuals (TheFreeDictionary.com).

Verbal noun of → collectivize.

1) The process of restricting a beam of photons or particles to a given area.
2) The process of adjusting a telescope to place all optical elements in precise alignment. → align a telescope.

Verbal noun of → collimate.

The act or process of colliding, → collide.

Verbal noun from → collide .

Of or relating to → collision.

→ collision; → -al.

Same as → cross section.

→ collisional; → cross; → section.

The process when the energy difference between the excited and non excited states of an atom is taken away by an electron during a collision.

→ collisional; → decay.

A physical process which is caused by the free electrons that are energized either by → photoionization or → collisional ionization. Collisional excitation puts ions, atoms, and molecules into excited states from which they may decay radiatively. Collisional excitation is important in the → interstellar medium.

→ collisional; → excitation.

A physical process whereby heat is imparted to (e.g. → interstellar dust grains or → molecular hydrogen) through collisions (with hot electrons, ions, etc.).

→ collisional; → heating.

An → ionization resulting from a → collision.

→ collisional; → ionization.

A plasma in which the → mean free path of the → charged particles between two → collisions is much smaller than the size of the system containing the plasma.

→ collisional; → plasma.

Same as the → Landau damping.

→ collision; → -less; → damping.

Empirical mathematical transformation applied to the observed magnitudes in order to convert them into a standard system, or into a different system.

→ color; → transformation.

Prefix denoting "together; with; joint; jointly". It is sometimes used for intensification as in complete, complain, convince.

M.E., from O.L., classical L. form cum "together, together with," Gk. koinos "common," from PIE *kom- "beside, near, by, with."

Ham- and ham "together, with; same, equally, even," Mid.Pers. ham-, like L. com- and Gk. syn- with neither of which it is cognate. O.Pers./Av. ham-, Skt. sam-, sa-; also O.Pers./Av. hama- "one and the same," Skt. sama-, Gk. homos-; originally identical with PIE numeral *sam- "one," from *som-. The Av. hąm- (nasal a) appears in various forms: ham-, han- (before gutturals, palatals, dentals) and also həm-, hən-, ha- (Bartholomae, 1772). Variants in Pers. ha- as in (Anâraki) ha-bend, → connect, and (Kurd.) hasûn "to whet, sharpen," and hâ- as in hâ-dâdan, hâ-gereftan, see Dehxodâ.

1) General: The act of combining or the state of being combined.
2) Math: The number of ways elements making up a set can be arranged into various groups without regard to their order in the group. → permutation

Noun from → combine

1) Any chemical reaction in which a substance (fuel) combines with oxygen to produce heat and often light. Combustion reactions usually involve a complex sequence of free-radical chain reactions. The light is produced by excited atoms, molecules, or ions.
2) → nuclear combustion.

M.E., from O.Fr. combustion, from L. combustionem (nominative combustio) "a burning," noun of action from p.p. stem of comburere "to burn," from → com-, intensive prefix + urere "to burn."

Suzeš, → burning