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

The linearization of the appropriate equations governing a system by the assumption of a steady state, with departures from that steady state limited to small perturbations. Also called perturbation method.

→ method; → small; → perturbation.

Of limited size; of comparatively restricted dimensions; not large. → method of small perturbations; → Small Magellanic Cloud (SMC).

M.E. smale; O.E. smæl "slender, narrow, small;" cf. Dan., Swed., M.Du., Du., O.H.G. smal, O.Fris. smel, Ger. schmal "narrow," Goth. smalista "smallest."

Kucak "small;" Mid.Pers. kucak "small," related to kutâh "short, small, little," kudak "child, infant," kutulé, → dwarf; Mid.Pers. kôtâh "low," kôtak "small, young; baby;" Av. kutaka- "little, small."
Kam "little, few; deficient, wanting; scarce," from Mid.Pers. kam "little, small, few," O.Pers./Av. kamna- "small, few."

Same as → Little Dipper.

→ small; → Little Dipper.

An irregular galaxy, the smaller of the two → Magellanic Clouds that are satellites of our own Galaxy, lying in the southern constellation → Tucana about 20 degrees from the → south celestial pole. The SMC covers an area roughly 3 by 5 degrees in dimension and has an overall → visual magnitude about +2.7. The SMC is about 10,000 → light-years in diameter and some 210,000 light-years (61 → kpc) away. It has a visible mass of about 1/50-th that of our Galaxy and 1/10-th of that of the → Large Magellanic Cloud (LMC). Its → heavy element content is about a factor 5 smaller than that of the Galaxy. The SMC is the third-nearest external galaxy after the → Sagittarius Dwarf Elliptical Galaxy and the LMC.

→ small; → Magellanic; → cloud.

A term introduced by the → International Astronomical Union (August 2006) to name the → solar system bodies other than → planets and → dwarf planets. Small solar system bodies include → asteroids, → comets, and → meteoroids.

→ small; → solar; → system; → body.

A Belgian facility devoted to the detection and characterization of → exoplanets and to the study of → comets (→ transiting planet) and other → small solar system bodies. It consists of two 60 cm robotic telescopes located at the → European Southern Observatory, → La Silla, in Chile and at Oukaïmden Observatory in Marroco.

→ transit; → planet; → planetesimal; → small; → telescope.

A special type of carbonaceous → interstellar dust grains with a size ranging from 10 to 150 Å and consisting of tens to hundreds of atoms. In contrast to → big grains, VSGs are not in → thermal equilibrium. They can be heated to very high temperatures (~ 1000 K) by the absorption of a single photon. It is thought that VSGs are clusters of → PAH.

→ very; → small; → grain.