An Etymological Dictionary of Astronomy and Astrophysics
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The Centaur. A → constellation in the southern hemisphere covering an extensive area of about 1060 square degrees from R.A. 11 h to 15 h and Dec. -30° to -64°. Abbreviation: Cen, genitive form: Centauri. Centaurus is the ninth largest constellation in the sky, but it does not contain any → Messier objects. The brightest star in constellation is → Alpha Centauri which is also the third brightest star in the sky. Beta Centauri, the second brightest star in Centaurus, also called → Hadar, is the eleventh brightest star in night sky. Among other bright stars of the constellation are: Menkent (θ Cen), γ Cen, ε Cen, and η Cen. There are three → meteor showers associated with the constellation: the Alpha Centaurids, the Omicron Centaurids, and the Theta Centaurids. The constellation contains several extragalactic objects, among which: Centaurus A (NGC 5128), Omega Centauri, and NGC 5139.

L. centaurus, from Gk. kentauros, cf. Av. gandarəwa- "a mythical monster killed by Kərəsâspa," Skt. gandharva- "name of mythical beings related with Soma." In Gk. mythology, centaurs were half-man half-horse creatures living on Mount Pelion in Thessaly, northern Greece. They were followers of the wine god Dionysus and well known for drunkenness and carrying off helpless young maidens.

Kentâwros, from Gk. "Kentauros." Arabicized Qenturis (قنطورس).

The closest (3.8 ± 0.1 Mpc) → radio galaxy with a physical age of about 560 Myr, associated with the massive → elliptical galaxy NGC 5128. The nucleus harbours a → supermassive black hole, with a mass (5.5 ± 3.0) × 10⁷ Msol derived from stellar → kinematics. A prominent → dust lane, with → starburst, crosses the central parts. Centaurus A shows a twin → jet in → radio and → X-ray bands, symmetrical on parsec scales but with evident asymmetry on kpc scales. The main (i.e. northern) jet which is markedly brighter than the counterjet, is seen at a viewing angle of approximately 50°. From photoionization models for such a viewing angle, the → Lorentz factor of the jet is derived to be ≤ 5. A large number of radio and X-ray → knots is discernible in the jet on kpc scales with the radio knots of larger proper motions showing comparatively little X-ray emission (see S. Wykes et al. 2015, MNRAS 447, 1005, and references therein).

Situated in the → Centaurus constellation.

The nearest large → supercluster. It is dominated by the → galaxy cluster A3526 (→ Abell catalog). The Centaurus supercluster is a long structure that stretches away from us. The most distant of the clusters, A3581, is about 300 million → light-years away.

→ Centaurus; → cluster.

The nearest → OB association to the Sun. It contains several hundred stars, mostly → B stars which concentrate in the three subgroups: Upper Scorpius, Upper Centaurus Lupus, and Lower Centaurus Crux. Upper Scorpius is the youngest subgroup, Upper Centaurus Lupus the oldest subgroup of the association. Isochrone fitting to the Hertzsprung-Russell diagram indicates that the star formation occurred some 5-20 Myr ago. Based on data from the → Hipparcos catalog, it turns out that the Sco-Cen association lies at a distance of 118-145 → parsecs, with the exact value depending on the subgroup of the association. The Sco-Cen association is probably a member of the → Gould Belt (Preibisch & Mamajek, 2008, astro-ph/0809.0407).

→ Scorpius; → Centaurus; → association.