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

A dip in a spectrum indicating that light has been absorbed on the path from the emitting source to the observer. It may be a line, corresponding to a well-defined atomic or molecular transition, or a more complex feature whose physical origin is not necessarily understood.

→ absorption; → feature.

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

→ coronal; → feature.

An emission or absorption mark in the spectrum of an astronomical object, the origin of which is attributed to the presence of dust in the object or on the line of sight.

→ dust; → feature.

Any emission mark in the spectrum of a celestial object resulting from line formation or of unknown origin.

→ emission; → feature.

A prominent or conspicuous part or characteristic. → absorption feature; → coronal features; → dust feature; → emission feature.

From O.Fr. faiture "fashion, shape, form," from L. facura "a formation," from facere "to make, do, perform" (cf. Fr. faire, Sp. hacer), from PIE base *dhe- "to put, to do" (cf. Mod.Pers. dâdan "to give;" O.Pers./Av. dā- "to give, grant, yield," dadāiti "he gives; puts;" Skt. dadáti "puts, places;" Hitt. dai- "to place;" Gk. tithenai "to put, set, place;" Lith. deti "to put;" Czech diti, Pol. dziac', Rus. det' "to hide," delat' "to do;" O.H.G. tuon, Ger. tun, O.E. don "to do").

Ârang "color; mode, form, manner," cf. Av. *iringa- "sign, mark" in haptôiringa- "with seven marks," from hapto- "seven," + iringa-; Mid.Pers. haptiring, Mod.Pers. haftowrang "the constellation of Great Bear;" cf. Skt. linga- "mark, token, sign."

An emission or absorption mark in the spectrum of an astronomical object, of known or unknown origin, usually with complex structure.

→ spectral; → feature.