An astrophysical maser is a naturally occurring source of stimulated spectral line emission, typically in the microwave portion of the electromagnetic spectrum. This emission may arise in molecular clouds, comets, planetary atmospheres, stellar atmospheres, or various other conditions in interstellar space.
HINT:
👉 Astrophysical maser in the context of OH/IR star
An OH/IR star is an asymptotic giant branch (AGB), a red supergiant (RSG), or a red hypergiant (RHG) star that shows strong OH maser emission and is unusually bright at near-infrared wavelengths.
In the very late stages of AGB evolution, a star develops a super-wind with extreme mass loss. The gas in the stellar wind condenses as it cools away from the star, forming molecules such as water (H2O) and silicon monoxide (SiO). This can form grains of dust, mostly silicates, which obscure the star at shorter wavelengths, leading to a strong infrared source. Hydroxyl (OH) radicals can be produced by photodissociation or collisional dissociation.
In this Dossier
- ⭐ Core Definition: Astrophysical maser
- 👉 Astrophysical maser in the context of OH/IR star
- Astrophysical maser in the context of Radio astronomy
Astrophysical maser in the context of Radio astronomy
Radio astronomy is a subfield of astronomy that studies celestial objects using radio waves. It started in 1933, when Karl Jansky at Bell Telephone Laboratories reported radiation coming from the Milky Way. Subsequent observations have identified a number of different sources of radio emission. These include stars and galaxies, as well as entirely new classes of objects, such as radio galaxies, quasars, pulsars, and masers. The discovery of the cosmic microwave background radiation, regarded as evidence for the Big Bang theory, was made through radio astronomy.
Radio astronomy is conducted using large radio antennas referred to as radio telescopes, that are either used alone, or with multiple linked telescopes utilizing the techniques of radio interferometry and aperture synthesis. The use of interferometry allows radio astronomy to achieve high angular resolution, as the resolving power of an interferometer is set by the distance between its components, rather than the size of its components.
View the full Wikipedia page for Radio astronomy