Homunculus Nebula - Shape

Shape

Some astrophysicists theorize the unusual shape of the Homunculus nebula can be attributed to a "peanut" shape of the star — or a binary star system (see below). It is believed that interacting blast waves from the brightening event(s) observed in 1841 have created a standing wave at the intersection of the two sides of the wave, gravitationally grouping the ejecta into a plane. It is possible, however, due to the solar-system-size nodes of the cloud, that some other mechanism — as yet unknown — is being witnessed. One theory holds that two small black holes may be present in the system, one at the center of each lobe, and one of which is consuming Eta Carinae (or one or both members of a binary star system previously misidentified as a singular Eta Carinae). The "skirt" of ejecta, according to this theoretical model, is proposed to be the result of a tangential release of the restraining gravity fields at the collision point.

The Homunculus-Eta Carinae system is currently one of the most massive that can be studied in great detail. Until 2005, this system was thought to contain the most massive single star known, but Eta Carinae was recently demoted to a binary system. Twenty-first century observations have indicated that the most massive star in the Eta Carinae multiple-star system probably has more than 100 times the mass of the Sun. Other known massive stars are significantly more luminous and more massive than Eta Carinae.