antitail pâddom Fr.: contre-queue A small tail-like structure on a comet that, unlike most comet tails, seems to point toward the Sun. This rare event is an optical illusion due to larger dust particles left along the comet's orbit. And typically occurs when the Earth crosses the plane of the comet's orbit. It seen when the observer is in the plane of the cometary orbit. Antitail, from → anti- "opposite, opposing, against" + → tail. Pâddom, from pâd-, → anti-, + dom "tail." |
cometary tail dome- donbâledâr Fr.: queue de comète A formation of → gas and/or → dust that streams away from the → coma of many comets under the influence of the Sun's → radiation pressure and the → solar wind. See also: → dust tail, → gas tail, → ion tail, → plasma tail, → sodium tail, → Type I tail, → Type II tail, → antitail. |
detail 1) pâzé; 2) pâzidan Fr.: 1) détail; 2) détailler 1) An individual or minute part; an item or → particular. From Fr. détail, from O.Fr. detail "small piece or quantity," literally "a cutting in pieces," from detaillier "to cut in pieces," from → de- "entirely" + taillier "to cut in pieces," from L. taliare "to split." Pâzé, from Sogd. pâzê "portion, bit;" Kurd. pâž "part of a whole;" related to Mod.Pers. baxš "part, division," bâž "tribute, toll, impost;" ultimately from Proto-Ir. *baj- "to bestow, divide, have a share;" cf. Av. baž- (baxš-) "to divide, bestow, give a share;" O.Pers. bāji- "tribute, tax;" Mid.Pers. bâj, bâž "tribute, tax," baxtan "to distribute," baxt "luck, fate;" Skt. bhaj- "to share, distribute, apportion," Gk. phagein "to eat (to have a share of food)"; PIE base *bhag- "to share out, apportion;" → division. |
detailed pâzemand Fr.: détaillé 1) Having many details. Adjective from → detail. |
dust tail donbâle-ye qobâri (#) Fr.: queue de poussière The tail of a → comet which is caused by → solar radiation pressure forcing the dust particles away from the → coma in a curved arch. Also called a → Type II tail. |
gas tail donbâle-ye gâzi Fr.: queue de gaz The → ionized component of a → comet's → tail, driven nearly straight away from the → Sun Sun by the → solar wind. solar wind. Also called → ion tail, → plasma tail, and → Type I tail. |
head-tail galaxy kahkešân-e sar-dom Fr.: galaxie tête-queue, ~ têtard A member of the class of radio galaxies (→ radio galaxy) that have a strong radio emission coming from a bright "head" and a more diffuse emission from a "tail." They are often found in clusters. |
ion tail donbâle-ye yoni (#) Fr.: queue d'ions Of a comet, same as → gas tail. |
magnetotail meqnâtdom Fr.: queue magnétique The portion of a planet's → magnetosphere which is pushed away from the Sun by the solar wind. Earth's magnetosphere extends about 65,000 km on the day-side but more than 10 times further. |
neutral tail dom-e natâr, donbâle-ye ~ Fr.: queue neutre Same as → sodium tail. |
plasma tail donbale-ye plâsmâyi Fr.: queue de plasma The ionized component of a comet's tail, driven nearly straight away from the Sun by the solar wind. Also called ion tail and gas tail. |
sodium tail dom-e sodiomi Fr.: queue de sodium 1) A kind of → cometary tail appearing in some
→ comets, such as → Hale-Bopp.
Sodium tails arise from the very strong → fluorescence
of their sodium atom → D lines
in the visible. They are rapidly accelerated
to high velocities by the Sun, forming a very straight tail distinct from the
→ ion tail.
The release mechanism of sodium from comets is still a matter of debate.
Also called → neutral tail. |
tail dom (#), donbâlé (#) Fr.: queue 1) The part that sticks out at the back of an animal's body, and that it can move. M.E.; O.E. tægl, from P.Gmc. *tagla- (cf. O.H.G. zagal, Ger. Zagel "tail," O.N. tagl "horse's tail"). Dom, variant domb, "tail;" Mid.Pers. dumb "tail;" Av. duma- "tail"; donbâlé, from domb + -âlé, -âl resemblance suffix, → -al. |
tidal tail donbâle-ye kešandi Fr.: queue de marée A long stream of stars and gas, often in the form of a spectacular tail, thrown off a galaxy when it collides with another galaxy. → interacting galaxies; → merger. Two tidal tails form in each galaxy, and they are more spectacular when the masses of the two galaxies are comparable, and when their relative orbit is in the same sense as the rotation inside each spiral galaxy. |
Type I tail dom-e gune-ye I Fr.: queue de type I The → gas tail of of a comet. |
Type II tail dom-e gune-ye II Fr.: queue de type II |