jofteš-e LS, jafsari-ye ~
Fr.: couplage LS
Same as → Russell-Saunders coupling.
The Wolf. A constellation in the southern hemisphere, located at about 15h right ascension, 45° south declination. Abbreviation: Lup; genitive: Lupi.
L. lupus "wolf," PIE *wlqwos/*lukwos; cf. Pers. gorg, as below; Gk. lykos; Albanian ulk; O.C.S. vluku; Rus. volcica; Lith. vilkas "wolf;" P.Gmc. *wulfaz (cf. O.S. wulf, O.N. ulfr, O.Fris., Du., O.H.G., Ger., E. wolf).
Gorg "wolf," Aftari dialect varg, M.Pers. gurg, O.Pers. Varkana- "Hyrcania," district southeast of the Caspian Sea, literally "wolf-land," today Iran Gorgân; Khotanese birgga-; Sogdian wyrky; Av. vəhrka-; Skt. vrka-.
Lupus dark cloud
abr-e târik-e Gorg
Fr.: nuage sombre du Loup
Any of the several → dark clouds lying in the direction of the constellation → Lupus between → Galactic longitudes 334° < l < 352° and → Galactic latitudes +5° < b < +25°. In terms of angular extent the whole group is one of the largest low-mass star forming complexes on the sky, and it also contains one of the richest associations of → T Tauri stars. An average distance of about 150 pc places it among the nearest star forming regions, together with those in Corona Australis, Ophiuchus, Taurus-Auriga, and Chamaeleon (Comeron, 2008, in Handbook of Star Forming Regions Vol. II, PASP, Reipurth, ed.).
Fr.: Boucle du Loup
An large nonthermal radio source in the constellation → Lupus, identified as a very old supernova remnant. It is also an extended source of soft X-rays.
Lysithea (Jupiter X)
The eleventh of Jupiter's known satellites; it is 36 km across and orbits Jupiter at a distance of about 11,720,000 km with a period of 259 days. It was discovered by S. Nicholson in 1938.
Lysithea was a daughter of Oceanus and one of Zeus' lovers.
Fr.: groupe mobile
A young → stellar population that shares a common space motion. A moving group remains kinematically distinct within the general field stars at ages < 1 billion years, before being dispersed. As progenitor gas is cleared by OB star winds, and the natal cluster expands, stars with sufficiently high velocities become unbound and form a young, coeval moving group, possibly leaving behind a bound open cluster. Because of their common origin, moving group members have a shared age and composition. The nearest moving group is the → TW Hydrae association.
Naos (ζ Puppis)
A bright, blue star of V = 2.25 in the constellation → Puppis. It is a hot → supergiant of type O5, with a → surface temperature of 42,000 K, lying 1,400 → light-years away. Naos is one of the rarest → O-type stars visible to the → naked eye.
Naos, from Gk. naos "ship," since it used to be the Zeta star of Argo Navis (Jason's vessel Argos) before becoming Zeta in Puppis.
Fr.: couple de Nasireddin
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.
The act of occupying; the state of being occupied.
Verbal noun of → occupy.
Fr.: niveau occupé
The energy level adopted by a particle, atom, or molecule under quantum mechanical laws.
To take or fill up (space, time); to take possession and control of a place.
From O.Fr. occuper, from L. occupare "take over, seize, possess, occupy," from ob "over" + intensive form of capere "to grasp, seize, take;" PIE base *kap- "to grasp" (cf. Skt. kapati "two handfuls;" Gk. kaptein "to swallow," O.Ir. cacht "servant-girl," literally "captive;" Goth. haban "have, hold;" O.E. habban "to have, hold," probably Mod.Pers. qâp-, qâpidan "to seize;" Av. haf-, hap- "to keep, observe."
Hagidan, from dialectal Pers.: Šahmirzâdi hâgetan, Saraxsi hagiton, Tabari hâytan, haytan, Semnâni hâtan, Gilaki hâgitan, Lâsgardi agiton, degiton "to occupy;" maybe related to Av. haz- "to occupy;" Skt. sah- "to overcome, be victorious, prevail," saha- "victory," sahate "overcomes, masters;" Gk. ekhein "to have, hold;" PIE base *segh- "to have, to hold."
Eightfold; eight times as great.
L. octuplus, from octu- variant (before labials) of → oct- octa- + -plus "fold," from base of plicare "to fold, twist."
Haštâyi, from hašt "eight," → oct- octa- + -tâyi, from tâ "fold, plait, ply; piece, part," also a multiplicative suffix; Mid.Pers. tâg "piece, part."
Fr.: Omicron (ο) Lupi
A bright star of → apparent visual magnitude V = 4.3 lying in the constellation → Lupus. Among its other designations: HD 130807, HR 5528, HIP 72683. It is an → early-type star of → spectral type B5 IV and a member of the → Scorpius-Centaurus association. Ο Lupi is in fact a → binary system whose components have an angular separation of 0.043 arcsec, corresponding to a physical separation of 5.3 → astronomical units, with a mass ratio of 0.91.
A group to which the speaker, the person spoken of, etc. does not belong.
abar-now-axtar-e nâpâydâri-ye joft
Fr.: supernova à instabilité de paires
A special type of → supernova that would result from the → pair instability in → supermassive stars with a mass range between 140 and 260 Msun in a low → metallicity environment. Such objects descended from the → Population III stars in the early history of the Universe. Such supernovae are the most powerful thermonuclear explosions in the Universe. Pair-instability supernovae may have played an important role in the synthesis of → heavy elements. Moreover, the energetic feedback of the processed elements to their surroundings could have affected the structure and evolution of the early Universe (See, e.g., Fryer et al. 2001, ApJ 550, 372; Heger & Woosley 2002, ApJ 567, 532). See also → pulsational pair-instability supernova.
periodically variable supergiant (PVSG)
abarqul-e vartande-ye dowreyi
Fr.: supergéante variable périodiquement
A variable → supergiant star with typical periods of the order of 10 to 100 days and amplitudes less than a few tenths of a magnitude. PVSGs are thought to be pulsating → g modes, caused by a density inversion, arising from an → opacity bump, most likely from Fe, H, and/or He.
Fr.: superamas de Persée-Poissons
A long, dense chain of galaxies with a length of almost 300 million → light-years, constituting one of the largest known structures in the → Universe. At the left end of the supercluster lies the massive → Perseus cluster (A426), one of the most massive clusters of galaxies within 500 million light-years.
platinum group element (PGE)
bonpâr-e goruh-e pelâtin
Fr.: élément du groupe du platine
One of the six metals → platinum (Pt), → iridium (Ir), → osmium (Os), → palladium (Pd), → rhenium (Rh), and → ruthenium (Ru) that are grouped together in the → periodic table. They are relatively hard and resistant to corrosion and are used in jewellery and in some industrial applications. All are resistant to chemical attack.
prompt supernova explosion
oskaft-e tond-e abar-now-axtar, ~ biderang-e ~
Fr.: explosion rapide de supernova
A mechanism predicted by theoretical models of → supernova explosion in the case when the → supernova shock breaks through the outer edge of the collapsing → iron core before losing all of its energy (through → photodisintegration of the iron nuclei) and manages to expel the stellar envelope. Compare with → delayed supernova explosion.