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

The → mid-infrared radiation which is scattered by unusually large → dust grains in the denser core regions of → molecular clouds. It occurs between 3 and 5 μm, when the light from nearby stars undergoes → scattering by the grains provided that they are about 1 μm in size, instead of 0.1 μm, as previously thought. Coreshine, which was detected in Spitzer IRAC data, is a widespread astronomical phenomenon. It is found across dozens of → dark clouds in the Galaxy and during all the phases of the → low-mass star formation (Pagani et al. 2010, Science, 329, 1622). See also → cloudshine.

→ core; → shine.

A quantity defined as f = 2ω.sinθ, where ω is the Earth's → angular velocity, 2π/T, T is the rotation period of the Earth (→ sidereal day), and θ is the → latitude. Also called the → Coriolis parameter. This frequency occurs often in oceanographic studies. If an → iceberg is floating in a frictionless sea, and is given a push and allowed to move freely, it will travel in a circle of radius U/f, where U is the initial speed imparted by the push. This circle is called an inertial circle.

→ Coriolis effect; → frequency.

The → absolute acceleration of a point P, which is moving with respect to a local → reference frame that is also in motion, is equal to the vector sum of:
a) the acceleration P would have if it were fixed to the moving system;
b) the acceleration of P with respect to the local moving system; and
c) a compound supplementary → Coriolis acceleration.

→ Coriolis effect; → theorem.

The Northern Crown. A small but prominent northern → constellation that lies east of → Arcturus, between → Boötes and → Hercules, and comprises a distinctive arc formed by the stars seven stars. Abbreviation: CrB; genitive: Coronae Borealis.

→ corona; L. borealis "northern."

Several phenomena occurring in the Sun's corona, such as a → helmet streamer, → polar plume, → coronal loop, → coronal hole.

→ coronal; → feature.

A bright, narrow stream of particles traveling through the Sun's corona, visible in images taken with a coronagraph or during a total solar eclipse. Coronal streamers represent the most outwardly extended structures in the solar corona and result from the interaction between the solar slow wind and the large-scale magnetic field. → helmet streamer.

→ coronal; → streamer.

A spiral-shaped density enhancement formed around a star when fast stellar winds collide with slower material. This large-scale wind structure can extend from the stellar surface to possibly several tens of stellar radii. The CIRs can be produced by intensity irregularities at the stellar surface, such as dark and bright spots, magnetic loops and fields, or non-radial pulsations. The surface intensity variations alter the radiative wind acceleration locally, which creates streams of faster and slower wind material. CIRs are responsible for the → discrete absorption components seen in some ultraviolet → resonance lines of → hot stars (S. R. Cranmer & S. P. Owocki, 1996, ApJ 462, 469).

→ corotate; → interaction; → region.

That condition of a → galactic disk at an orbital radius in which the → angular velocity of the disk equals the → pattern speed. It is significant that the spiral wave pattern rotates as a rigid body (Ω_P = const), whereas the galactic disk rotates differentially (Ω is a function of galactocentric distance r). The distance r_C at which the two angular velocities coincide (Ω(r_C) = Ω_P) is referred to as the → corotation radius. The corotation resonance and its position within the galaxy is one of the fundamental properties of a spiral galaxy.

→ corotation; → resonance.

1) Free from error; conforming to an acknowledged or accepted standard or fact; true or accurate.
2) To remove the errors or mistakes from. → bolometric correction, → correcting plate, → correction, → corrector, → ionization correction factor, → K correction, → Malmquist correction, → Rydberg correction, → wavefront correction.

From L. correctus, p.p. of corrigere "make straight, put right," from → com- intens. prefix + regere "to guide, direct, rule," cf. Av. raz- "to direct, lead," razišta- "straightest, most correct," erezu- "correct, straight," râzayeiti "directs," O.Pers. râs- "to be right, straight, true," râsta- "staright, true," Mod.Pers. râst "right, straight, true," Skt. raj- "to direct, stretch," rjuyant- "walking straight," Gk. orektos "stretched out," Ger. recht, E. right; PIE base *reg- "right, just; to move in a straight line."

1) Aršâ, from Av. arš, ereš, erež "rightly, truly," as in arš.dâta- "rightly made," arš.manah- "whose thinking is right," arš.vacah- "whose speaking is right," erešya- "righteous, just," cf. O.Pers. arta- "law, justice," Skt. rta- "cosmic order," Gk. arti "just," artios "complete;" PIE base ar- "to fit together, join."

Note: For the sake of clarity, we avoid the Persian term dorost because its dominant meaning is "entire, complete, whole, safe, sound," although it means also "accurate, correct." Etymology: Mid.Pers. drust "straight, right, healthy," drôd "health, thriving," Parthian rwd "health, thriving," O.Pers. duruva- "firm, certain, immune," Av. drava- "healthy," Skt. dhruva- "fixed, firm, lasting," druh- "to be firm," Proto-Iranian *druua-.
2) Aršâyidan, verb from aršâ "correct."

A large glass plate placed at the entrance of a Schmidt telescope to correct for spherical aberration over the large field of view.

→ correct; → plate.

1) The act or process of correcting.
2) A quantity added to a calculated or observed value to obtain the true value.
3) Something that is substituted or proposed for what is wrong or inaccurate.

Noun form of → correct.

A thin lens-like optical piece which removes certain optical aberrations.

→ correct + → -or.

1) To place in or bring into causal or mutual relation.
2) To have a mutual or reciprocal relation.

From co-, → com-, + relate, → relation

Hambâzânidan , from ham-→ com- + bâzânidan→ relate.

General: The degree to which two or more attributes or measurements on the same group of elements show a tendency to vary together; the state or relation of being correlated.
Statistics: The strength of the linear dependence between two random variables.

From M.Fr. corrélation, from cor- "together," → com- + → relation.

Hambâzâneš , from ham-→ com- + bâzâneš→ relation.

A number between -1 and 1 which measures the degree to which two variables are linearly related.

→ correlation; → coefficient.

In radio astronomy a general term for → autocorrelator and → cross-correlator.

→ correlate + → -or.

A plot showing a summary of correlation at different periods of time.

Correlo-, from → correlation; → -gram.

To be in agreement, harmony, or conformity; to be similar or equivalent in character, quantity, origin, structure, or function.

From O.Fr. Fr. correspondre, from M.L. correspondere from cor-, → com-, + respondere "to answer," → response.

Hampatvâzidan, from ham-, → com-, + patvâz "response" [Mo'in], from Mid.Pers. patvâc "response," Av. paitivak- + -idan infinitive suffix.

The act, fact, or state of agreeing or conforming.

Verbal noun from → correspond.

The principle first put forward by N. Bohr according to which the behavior of quantum mechanical laws reduce to classical laws in the limit of large quantum numbers.

→ correspondence; → principle.