An Etymological Dictionary of Astronomy and Astrophysics
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A suffix meaning "instrument for viewing," used in the formation of compound words, such as → telescope, → microscope; → spectroscope.

N.L. -scopium, from Gk. -skopion, -skopeion, from skopein "to behold, look, consider," skeptesthai "to look at;" PIE base *spek- "to see;" cf. Av. spasiieiti "looks at, perceives," spas- "spy;" Skt. paś- "to see, watch," spasati "sees;" L. specere "to look at;" O.H.G. spehhon "to spy," Ger. spähen "to spy."

-bin, short for binandé "seer," present stem of didan "to see," from Mid.Pers. wyn-; O.Pers. vain- "to see;" Av. vaēn- "to see;" cf. Skt. veda "I know;" Gk. oida "I know," idein "to see;" L. videre "to see;" PIE base *weid- "to know, to see."
-nemâ, present stem of nemudan "to show;" Mid.Pers. nimūdan, nimây- "to show," from O.Pers./Av. ni- "down; into," → ni- (PIE),+ māy- "to measure;" cf. Skt. mati "measures," matra- "measure;" Gk. metron "measure;" L. metrum; PIE base *me- "to measure."

A suffix used to form abstract action nouns corresponding to nouns with stems ending in → -scope.

From Gk. -skopia, → -scope + -ia.

-bini, from -bin, → -scope, + -i noun suffix.

A combining form used in the names of devices that stabilize or make constant what is specified by the initial element, e.g. → cryostat; → thermostat.

From Gk. -states, from sta- stem of histanai "to make stand," histemi "put, place, weigh," stasis "a standing still;" L. stare "to stand;" Pers. ist "to stand; to be standing, "from istâdan "to stand;" Mid.Pers. êstâtan; O.Pers./Av. sta- "to stand, stand still; set;" Av. hištaiti; cf. Skt. sthâ- "to stand;" PIE base *sta- "to stand."

Suffix -pâ, -pây present stem of pâyidan "to stand firm, to be constant, steady," from Mid.Pers. pattây-, pattutan "to last, endure, stay."

The only supernova seen to date in the Andromeda galaxy and the first supernova observed beyond our own Galaxy. It was recorded on Aug. 20, 1885, by Ernst Hartwig (1851-1923) at Dorpat Observatory (Tartu) in Estonia and independently by other astronomers. S Andromedae reached magnitude 6 between Aug. 17 and 20, and had faded to magnitude 16 by February 1890. It is now believed that S Andromedae was a Type Ia supernova. Also known as SN 1885A.

S, from the second variable star to be discovered in constellation → Andromeda

A moderately bright type of asteroids (albedo 0.10 to 0.22) consisting mainly of iron- and magnesium-silicates such as olivine and pyroxene. They are dominant in the inner main belt within 2.2 AU, common in the central belt within about 3 AU, but become rare further out. The largest is 15 Eunomia (about 330 km in its largest dimension).

S stands for silicaceous, → silicate; → asteroid.

A → star cluster situated within an arcsecond, or 0.04 pc, from the → Galactic Center, in the vicinity of the → supermassive black hole Sgr A*. The cluster members are about 40 → main sequence → B-type stars with relatively high orbital → eccentricities (0.3 ≤ e&le 0.95). The most famous member of the S cluster is S2 because of its brightness and its fast orbital motion near Sgr A*. Same as Same as the Sgr A* cluster and S stars. See also other → Galactic center clusters (Figer et al. 2002, ApJ 581, 258; and 1999, ApJ 525, 750).

S, because of proximity to → Sgr A*; → cluster.

A type of massive, → blue supergiant, → variable star, also known as a → Hubble-Sandage variable or a → Luminous Blue Variable (LBV). S Doradus stars are the most luminous stars in the Galaxy and are easily identified in other nearby galaxies. They are named after the prototype, S Doradus, in the → Large Magellanic Cloud.

→ Dorado; → star.

A → red giant of → spectral type S whose spectrum is dominated by → molecular bands arising from → zirconium → oxide (ZrO). S stars also have strong → cyanogen bands and contain spectral lines of → lithium and → technetium. Almost all S stars are → long-period variables.

S, letter of alphabet; → star.

A → nucleosynthesis process by which → chemical elements heavier than → copper are formed through a slow flux of → neutrons absorbed by atomic nuclei (→ neutron-capture element). The → capture of neutrons occurs on time scales that are long enough to enable unstable nuclei to decay via the emission of a → beta particle before absorbing another neutron. Prominent s-process elements include → barium, → zirconium, and → yttrium. See also: → r-process.

s stands for → slow; → process.

A type of → asteroid containing → pyroxene and → olivine silicates, probably mixed with metallic iron, similar to → stony meteorites. S-type asteroids show high albedo of 0.10-0.22. They include about 17% of known asteroids and occupy the inner → asteroid belt.

S for → stone; → type; → asteroid.

Same as → S star.

S, letter of alphabet; → type; → star.

→ shear wave.

S, referring to → shear; → wave.

The fastest → main sequence  → hypervelocity star (HVS) with a → heliocentric  → radial velocity of 1017 ±2.7 km s^-1. The star S5-HVS1 is an → A-type with a → luminosity of ~ 2.35 Msun located at a distance of ~ 9 kpc from the Sun. The current 3D velocity of the star in the Galactic frame is 1755 ± 50 km s^-1. When integrated backwards in time, the orbit of the star points unambiguously to the → Galactic Center, implying that S5-HVS1 was kicked away from → Sgr A* with a velocity of ~ 1800 km s^-1 and travelled for 4.8 Myr to its current location. This is so far the only HVS confidently associated with the Galactic Center. The ejection trajectory and transit time of S5-HVS1 coincide with the orbital plane and age of the annular disk of young stars at the Galactic Centre, and thus may be linked to its formation. With the S5-HVS1 ejection velocity being almost twice the velocity of other hypervelocity stars previously associated with the Galactic Center, the question arises whether they have been generated by the same mechanism or whether the ejection velocity distribution has been constant over time (Koposov, S.E., et al., 2019, arXiv:1907.11725).

S5, or S⁵, short for Southern Stellar Stream Spectroscopic Survey; HVS, → hypervelocity star (HVS).

The effect of → gravitational potentials on the → anisotropy of the → cosmic microwave background radiation, in which photons from the → CMB are gravitationally → redshifted, causing the CMB spectrum to appear uneven. This effect is the predominant source of fluctuations in the CMB for angular scales above about 10 degrees. It involves two parts: the effect of the potential at the → surface of last scattering, which is the ordinary Sachs-Wolfe effect. And the integrated Sachs-Wolfe (ISW) effec, which is caused by the time variation of gravitational potentials as the photons travel through them. A photon traveling through a decaying → potential well (wall) gains (loses) energy. Without → dark energy the photon is → blueshifted and then → redshifted, so that both effects compensate each other. On the other hand, in an → accelerating Universe driven by dark energy the photon gets more blueshifted. See also → Rees-Sciama effect.

Rainer Kurt Sachs (1932- ) & Arthur Michael Wolfe (1939- ), 1967, ApJ 147, 73; → effect.

An almost horizontal region in the → CMB angular power spectrum belonging to a → multipole index 10 ≤ l ≤ 100. This feature is due to the → Sachs-Wolfe effect.

→ Sachs-Wolfe effect; → plateau.

A supergiant star of type G2 Ib situated in the constellation → Aquarius. At a distance of 750 light-years, it has a luminosity 3000 times that of the Sun, and a diameter about 60 times the solar diameter. Variant designations: Sadalmelek; Sadlamulk; El Melik; Saad el Melik.

From Ar. Sa'd al-Malik (سعد الملک) "the lucky star of the ruler," for unknown reasons.

The star that lies at the center of → Cygnus's → Northern Cross. This F8 → supergiant is situated some 1,500 → light-years away and has an → apparent visual magnitude of 2.20.

From Ar. as-sadr (الصدر) "breast" (of the Cygnus).

The Arrow. A very small → constellation, in fact the third smallest constellation in the sky, lying south of → Vulpecula, and north of → Aquila. The constellation contains the prototype → WZ Sagittae star and M71 (NGC 6838), formerly thought to be an → open cluster but now considered to be a → globular cluster of low condensation. Its brightest star α Sge is a yellow bright → giant of → apparent magnitude +4.37 and → spectral type G1 II about 475 → light-years from Earth. Abbreviation: Sge; Genitive: Sagittae.

From L. sagitta "arrow."

Peykân, → arrow.

The Archer. A large constellation belonging to the → Zodiac, situated between → Scorpius and → Capricorn. It is located in the southern hemisphere at approximately 19h right ascension, 25° south declination. The constellation, part of which lies in the → Milky Way, contains the → Trifid Nebula, → Lagoon nebula, star clusters, and globular clusters. The center of the Galaxy lies in the direction of Sagittarius. Abbreviation: Sgr; Genitive: Sagittarii.

From L. sagittarius "archer," literally "pertaining to arrows," from → sagitta "arrow" + -arius "-ary." In Gk. mythology, Sagittarius is identified as a centaur, half human, half horse. In some legends, the Centaur Chiron was the son of Philyra and Saturn, who was said to have changed himself into a horse to escape his jealous wife, Rhea. Chiron was eventually immortalized in the constellation of → Centaurus, or in some version, Sagittarius.

Nimasb, from Mid.Pers. nêmasp "centaur, Sagittarius," from nêm, nêmag "mid-, half" (Mod.Pers. nim); Av. naēma- "half;" cf. Skt. néma- "half" + asp "horse" (Mod.Pers. asb); O.Pers. asa- "horse;" Av. aspa- "horse," aspā- "mare," aspaiia- "pertaining to the horse;" cf. Skt. áśva- "horse, steed;" Gk. hippos; L. equus; O.Ir. ech; Goth. aihwa-; O.E. eoh "horse;" PIE base *ekwo- "horse."

A strong radio source at the center of our Galaxy. It is a complex object with three components: Sgr A West is a thermal radio source made of several dust and gas clouds, which orbit → Sgr A* and fall onto it at velocities as high as 1000 km per second. Sgr A East is a → non-thermal source, about 25 → light-years across, that appears to be a → supernova remnant. Sgr A* is the most plausible candidate for the location of a Galactic → supermassive black hole with a mass of about 4 million → solar masses.

→ Sagittarius.