The constellation of Capricornus is not noted for its bright stars, but the brightest of the group is Deneb Algedi, with a visual magnitude of +2.8. It lies in the eastern part of the constellation, among the stars traditionally representing the twining fish-like tail of the star-goat, and indeed the name Deneb Algedi (sometimes spelt Deneb Algiedi) means 'tail of the goat'. The star falls close to the Ecliptic, near the point where it passes out of Capricornus and on into neighbouring Aquarius.
Deneb Algedi is a complex stellar system that lies some 39 light years from the Sun. At its heart is a white giant that has entered the later stages of its evolution, shining by fusing the helium in its core, having consumed its reserves of hydrogen. Whirling around with this giant star is a yellow-orange dwarf star, whose rapid orbit eclipses its larger companion and causes its brightness to dip regularly over a period of just over one day. Much farther out from the central star appear to be two more faint stellar companions, designated Deneb Algedi B and Deneb Algedi C.
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