Diamond Cross

A formation of four stars in the southeastern regions of Carina, forming a distinct diamond shape pointing out from the Milky Way towards the Large Magellanic Cloud. The four stars that compose the Diamond Cross are Miaplacidus, Vathorz Prior, Vathorz Posterior and Omega Carinae. All four of these stars are third magnitude or brighter, with the brightest being Miaplacidus (magnitude +1.66) and the faintest Omega Carinae (magnitude +3.29).

As for most constellations and asterisms, the four stars of the Diamond Cross are not actually related to one another, but simply form their distinctive shape from the viewpoint of an observer on Earth. The closest of the four to the Solar System is Miaplacidus, a white subgiant some 113 light years from the Sun. The most distant is Vathorz Prior, a supergiant that is actually much more luminous than Miaplacidus, but also lies more than ten times farther from the Sun.

The star that forms the easternmost corner of the Diamond Cross is Vathorz Posterior, a blue star notable as lying within the prominent cluster known as the Southern Pleiades, an open cluster of about fifty related stars lying some five hundred light years from the Solar System.

The Diamond Cross is one of three 'cross' formations in the same general region of the southern sky. Close by to the east lies the rather more prominent constellation of the Southern Cross, Crux. To the north and west, reaching across the border from Carina into Vela, is the False Cross, an asterism with a similar configuration to Crux. Both these other 'cross' formations are cruciform arrangements of stars, and so the Diamond Cross stands out between them as having a more distinctly diamond-shaped structure.