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

A solid-state detector that stores the electrons, produced by incident photons, in potential wells at the surface of a semiconductor. The packages of charge are moved about the surface by being transferred to similar adjacent potential wells. The wells are controlled by the manipulation of voltage applied to surface electrodes.

→ charge; coupled adj. from → couple; → device.

1) General: Two items of the same kind; a pair; something that joins or connects two things together; a link.
2) A system of two equal and opposite, parallel, but not → collinear forces acting upon a body.
3) To fasten, join together; connect. See also → coupled, → coupled system, → charge-coupled device, → coupling, → decouple, → galvanic couple, → Nasireddin couple, → pair; → parity, → thermocouple.

1) joft "pair, couple," Lori, Laki jeft, Qâyeni jof, Tabari jeft, Mid.Pers. yuxt "pair, couple," Av. yuxta- "a team of horses," from yaog- "to yoke, harness, put to; to join, unite," infinitive yuxta, Mid.Pers. jug, ayoxtan "to join, yoke," Mod.Pers. yuq "yoke," cf. Skt. yugam "yoke," Gk. zygon "yoke," zeugnyanai "to join, unite," L. jugare "to join," from jugum "yoke," P.Gmc. *yukam, E. yoke; PIE *yeug- "to join."
2) joftniru, from joft as above + niru, → force.
3) Joftidan, infinitive from joft, → couple; jafsar kardan infinitive from jafsar, → coupled, + kardan "to do, to make."

Joined together, connected by a link. → coupled system, → charge-coupled device.

Adj. from → couple.

Jafsar "connected, joined pair," in Tâleši, from jaf, variant of joft, as above + sar "head," literally "joined by head" (Mid.Pers. sar, Av. sarah- "head," Skt. siras- "head," Gk. kara "head," keras "horn," Mod.Pers. sarun "horn," L. cerebrum "brain;" PIE *ker- "head, horn"); joftidé adj./p.p. from joftidan, → couple.

A set of two or more mechanical vibrating systems connected so that they interact with one another.

→ coupled; → system;

1) To separate or detach; to cause to become disconnected or divergent.
2) Electronics: To reduce or eliminate the coupling of (one circuit or part to another).
3) Physics: To decrease or eliminate the shock waves of a nuclear explosion by having it take place underground.

→ de- + → couple.

A pair of dissimilar conductors, commonly metals, in electrical contact.

→ galvanism; → couple.

A central, tightly bound stellar subsystem observed in some elliptical galaxies which rotates in the opposite direction with respect to the main body of the → elliptical galaxy. Elliptical galaxies are thought to be the result of the → merger of two or more sizable galaxies. A plausible scenario for how counter-rotating cores could form in such a merger is as follows. If at least one of the galaxies has a core region that is fairly tightly bound by the galaxy's gravity, and the direction in which the two galaxies orbit each other before merging is opposite to the direction of rotation of stars in that tightly bound core, it is likely that, after the merger, the tightly bound core will end up as the core of the new, larger galaxy, while retaining its original sense of rotation. The surrounding stars, on the other hand, will rotate in a different way dictated by the orbital motion of the galaxies around each other, before the merger. While this is a plausible scenario, it can only explain some of the counter-rotating cores. Recently A. Tsatsi et al. (2015, ApJ 802, L3) have shown that although the two → progenitor galaxies are initially following a → prograde orbit, strong reactive forces during the merger can cause a short-lived change of their orbital spin; the two progenitors follow a → retrograde orbit right before their final coalescence. This results in a central kinematic decoupling and the formation of a large-scale (~2 kpc radius) counter-rotating core at the center of the final elliptical-like merger remnant, while its outer parts keep the rotation direction of the initial orbital spin.

→ kinematical; → decouple; → core.

A theorem put forward by the 13th century Persian mathematician and astronomer Nasireddin Tusi to generate linear motion from a combination of circular motions, and thus improve the geocentric model of Ptolemy. A circle of radius R rotates inside a circle of radius 2R. The smaller circle rotates at twice the speed of the larger one and in opposite direction. The initial tangent point will travel in linear motion back and forth along the diameter of the larger circle. A particular case of → hypocycloid curves.

Named for Nasireddin Tusi (1201-1274), director of Marâgha observatory who created the Ilkhani zij; → couple.

Electrical circuit consisting of two dissimilar metals, in which an electromotive force is produced when the two junctions are at different temperatures.

→ thermo- + → couple.

→ Nasireddin couple.

Named for Nasireddin Tusi (1201-1274), director of Marâgha observatory who created the Ilkhani zij; → couple.