Herbig–Haro (HH) objects are bright patches of nebulosity associated with newborn stars.They are formed when narrow jets of partially ionised gas ejected by stars collide with nearby clouds of gas and dust at several hundred kilometres per second. Herbig–Haro objects are commonly found in star -forming regions and several are often seen around a single star aligned with its rotational axis.
Formation . A Thorne–Żytkow object is formed when a neutron star collides with another star typically a red giant or supergiant.The colliding objects can simply be wandering stars. This is only likely to occur in extremely crowded globular clusters.Alternatively the neutron star could form in a binary system after one of the two stars went supernova .
A protostar is a very young star that is still gathering mass from its parent molecular cloud.The protostellar phase is the earliest one in the process of stellar evolution. For a low mass star (i.e. that of the Sun or lower) it lasts about 500 000 years. The phase begins when a molecular cloud fragment first collapses under the force of self-gravity and an opaque pressure supported core …
Protostar – Wikipedia
Herbig–Haro object – Wikipedia
Stellar evolution is the process by which a star changes over the course of time. Depending on the mass of the star its lifetime can range from a few million years for the most massive to trillions of years for the least massive which is considerably longer than the age of the universe.The table shows the lifetimes of stars as a function of their masses.
A supernova (/ ˌ s uː p ər ˈ n oʊ v ə / plural: supernovae / ˌ s uː p ər ˈ n oʊ v iː / or supernovas abbreviations: SN and SNe) is a powerful and luminous stellar explosion.This transient astronomical event occurs during the last evolutionary stages of a massive star or when a white dwarf is triggered into runaway nuclear fusion.The origin…