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

A three-dimensional section of the → radiation pattern ofa directional antenna, bounded by one or more cones of nulls or by regions of diminished irradiance.

→ antenna; → lobe.

A small globe representing the celestial sphere, on which the apparent positions of the stars are indicated.

→ celestial; → globe.

A → galaxy that emits radio energy from two regions located on opposite sides of the galaxy.

→ double; → lobe; → radio; → source.

A spherical body; sphere.
The planet Earth (usually preceded by the). A sphere on which is depicted a map of the Earth (terrestrial globe) or of the heavens (celestial globe).

M.E. globe, from M.Fr. globe, from L. globus "round body, ball, sphere," cognate with Pers. guy, see below.

Guy "ball, sphere," variants golulé, gullé, goruk, gulu, gudé; cf. Skt. guda- "ball, mouthful, lump, tumour," Pali gula- "ball," Gk. gloutos "rump," L. glomus "ball," globus "globe," Ger. Kugel, E. clot; PIE *gel- "to make into a ball."

General: A roundish projection that is part of a larger structure.
Radioastronomy: In an antenna pattern, a region of local maximum in the emitted intensity. The strongest lobe is in the pointing direction of a directional antenna and is called the main lobe.
Quasar: One of the two lobe-like structures well apart from the central source, observed in radio images of some quasars. Same as radio lobe.

From M.L. lobus, from L.L. lobus "hull, husk, pod," from Gk. lobos "lobe of the ear, vegetable pod," probably related to leberis "husk of fruits;" from PIE base *lep- "to peel, flay."

Lap "lobe," variants lâp, lâb "piece, big piece, big cut," lappé "split pea; any of the two parts of a timber split through the length," maybe cognate with Gk. lobos, as above. Alternatively, related to Pers. las "loose," PIE *leu- "to loosen, divide, cut apart" (cf. Gk. lyein "to loosen, untie, slacken," lysus "a loosening;" L. luere "to loose, release;" → analysis).

The configuration of the response lobes of a radiotelescope.

→ lobe; → pattern.

A → radio-loud quasar in which the lobes dominate the whole emission. It has been conjectured that this phenomenon is an → orientation effect. If the → jet is close to the plane of the sky, the lobes will dominate. See also → core-dominated quasar.

→ lobe; → dominate; → quasar.

The lobe in the reception pattern of a radio telescope that includes the region of the maximum received power. Also called major lobe and main beam.

→ main; → lobe.

An extended region of diffuse radio emission, often dumbbell shaped, that surrounds a radio galaxy.

→ radio; → lobe.

The region around a star in a → binary system within which orbiting material is gravitationally bound to that star. The point at which the Roche lobes of the two stars touch is called the → inner Lagrangian point. → equipotential surface.

→ Roche limit; → lobe.

A process in a → binary system when a star fills its → Roche lobe, often by becoming a → giant or → supergiant during the later stages of → stellar evolution. When the star expands, any material that passes beyond the Roche lobe will flow onto the binary → companion, often by way of an → accretion disk. This occurs through the → inner Lagrangian point where the gravity of the two stars cancels. The RLOF is responsible for a number of phenomena including → cataclysmic variables, → Type Ia supernovae, and many → X-ray binary systems.

→ Roche lobe; → overflow.

1) In → radio astronomy, smaller amounts of gain found either side of the main lobe.
2) In transmitting antennae, radiation in any direction other than that required.

→ side; → lobe.