Southern Crab Nebula

The Southern Crab Nebula or Hen 2-104 is a bipolar nebula, as viewed from Earth in the constellation Centaurus and is several thousand light- years away from Earth. Its central object is a symbiotic star consisting of a Mira star and a white dwarf.

The fog is probably from Mira abgestoßenem from material that is ionized by the energetic radiation of the white dwarf and thus brought to light. The mass of the ionized nebula is estimated to be about one- tenth of a solar mass, which is significantly higher than other symbiotic mists. The high mass loss suggests that the Mira is located in a highly developed stage, close to the asymptotic giant branch.

The distance from Hen 2-104 is unknown and difficult to determine. Using different methods, estimates are obtained kpc in the order of between 1 and 8. Recently certain Corradi et al. using the period- brightness relation of Mira- stars a distance of 4.4 kpc and Santander - García et al. estimated with the help of a provision of the expansion parallax using the Hubble Space Telescope, the distance ( 3.5 ± 0.7 ) kpc for the Jets and ( 3.1 ± 0.9) kpc for the outer shells.

The adjective south Hen 2-104 differs from the Crab Nebula, which is located at the northern sky.

Hen 2-104 was discovered in 1967 by Karl Henize as a point source and classified as a planetary nebula because of its emission lines. Only in 1989 the extended nebula was discovered and named Southern Crab Nebula. Was found the fog with the 2.2 - m ESO telescope at La Silla (Chile), but the images from the Hubble Space Telescope from 1999 show much more detail, including that the center of the nebula consists of a pair of stars from a red giant and a white dwarf.