Herbig–Haro 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. First observed in the late 19th century by Sherburne Wesley Burnham, they were recognised as a distinct type of emission nebula in the 1940s. Most of them lie within about one parsec of the source, although some have been observed several parsecs away.
About Herbig–Haro object in brief
Herbig–Haro 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. First observed in the late 19th century by Sherburne Wesley Burnham, they were recognised as a distinct type of emission nebula in the 1940s. The first astronomers to study them in detail were George Herbig and Guillermo Haro, after whom they have been named. Most of them lie within about one parsec of the source, although some have been observed several parsecs away. HH objects are transient phenomena that last around a few tens of thousands of years. They can change visibly over timescales of a few years as they move rapidly away from their parent star into the gas clouds of interstellar space. Hubble Space Telescope observations have revealed the complex evolution of HH objects over the period of a several years, as parts of the nebula fade while others brighten as they collide with the clumpy material of the interstellar medium. In 1975 American astronomer R. D. Schwartz theorized that winds from T Tauri stars produce shocks in the ambient medium on encounter, resulting in generation of visible light. With the discovery of the first proto-stellar jet in HH 4647, it became clear that HH objects were indeed shock-induced phenomena with shocks being driven by a collimated jet from protostars. The Soviet astronomer Viktor Ambartsumian gave the objects their name, and based on their occurrence near young stars suggested they might represent an early stage in the formation of T Tauris.
At these distances, the outflow is divergent at an angle in the range of 10°−30°, but becomes increasingly increasingly closer at distances of up to 10°. At this distance, the material within a few astronomical units of the star disk becomes increasingly collimated, and the stellar magnetic field accelerates some of the accreting material from the accretion disk. Some of the material is ejected out along the star’s rotation in a process called outreting. The core of the core in this system is called a protostar, and is ejected along the axis of rotation in two directions. This process continues to fall towards a state of hydrostatic equilibrium until a loss of rotating axis is established. This is known as a’static equilibrium’ and is established in a star’s core in a system called a Tauri star. In this state, the core of this system continues to rotate along the rotational axis of the disk in two different directions, and this is called the rotation of the Tauri disk. The Tauri core is ejected from the disk along the rotation in the direction of these outflow outflow in which it becomes increasingly out of the plane of these distances. In the early 1900s, the first HH object was observed by Sherburne Wesley Burnham. It was found to be a very young and variable star and is the prototype of the class of similar objects known as T T Lauris stars.
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This page is based on the article Herbig–Haro object published in Wikipedia (as of Nov. 04, 2020) and was automatically summarized using artificial intelligence.
