Crux is a constellation located in the southern sky in a bright portion of the
Milky Way, and is the
smallest but one of the most distinctive of the 88 modern
constellations. Its name is
Latin for
cross, and it is dominated by a cross-shaped or kite-like
asterism that is commonly known as the
Southern Cross. Predominating the asterism is the most southerly first-magnitude star and brightest star in the constellation, the blue-white
Alpha Crucis or Acrux, followed by four other stars, descending in clockwise order by magnitude:
Beta,
Gamma (one of the closest
red giants to Earth),
Delta and
Epsilon Crucis. Many of these brighter stars are members of the
Scorpius–Centaurus Association, a large but loose group of hot blue-white stars that appear to share common origins and motion across the southern
Milky Way. Two of the star systems have been found to have planets. The constellation also contains four
Cepheid variables that are visible to the naked eye under optimum conditions. Crux also contains the bright and colourful
open cluster known
Jewel Box (NGC 4755) and, to the southwest, the extensive
dark nebula, known as the
Coalsack Nebula.
