HII Regions - Stellar Nurseries
The Orion Nebula - A stellar nursery
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NASA ...
HII REGION - Volume of space where H in the interstellar medium is ionized rather than in a neutral state.
HII region: A region of ionized hydrogen around a hot star.
Hirayama families: Families of asteroids with orbits of similar size, shape, and orientation; believed to be fragments of larger bodies.
HII Region - A region of ionized hydrogen surrounding a hot star. Ultraviolet radiation from the star keeps the gas in the HII region ionized ...
UC HII regions
Ultra-compact HII regions are among the best tracers of high-mass star formation. The dense material surrounding UCHII regions is likely primarily molecular.
Compact HII Region
A dense (ne 103 cm-3) H II region of small linear dimensions ( 1 pc).
Compact Infrared Sources ...
HII Region: "HII" (pronounced H two) is ionized hydrogen. (The roman numeral refers to the ionization state. I means neutral, II means one electron ionized, III means two electrons ionized, etc.
HII regions: hot (10000K) ionized hydrogen surrounding hot O and B type stars. Detected by optical emission, particularly the red H alpha emission line.
HI regions: cold (100K) regions of neutral hydrogen detected by 21 cm radio emission.
An HII region ionized by Zeta Persei. [H76]
Californium
A silvery radioactive transuranic element of the actinoid series of metals, not found naturally on Earth.
8. An HII region is another name for an _____. (Hint)
9. Dark dust clouds can have temperatures as low as _____ K. (Hint)
10. 21-cm radiation is emitted by _____ hydrogen. (Hint) ...
NGC 3603, a giant HII region in the Milky Way. Ultraviolet light from the young star cluster in the centre of the nebula is heating and ionising the surrounding hydrogen gas.
Emission lines are produced by many astrophysical processes such as those found in emission nebulae (including planetary nebulae and HII regions), quasars and the some stars such as Wolf-Rayets.
Star-forming regions (SFR), in the form of molecular clouds and giant molecular clouds (sometimes known by the related term HII regions), support the bulk of astrophysical masers.
The high-energy UV photons responsible for the ionisation of hydrogen atoms in HII regions are not only found close to hot, massive stars.
In star-forming regions, the OB stars are responsible for generating HII regions -- the regions of red, nebulous patches generated by ionization and recombination of hydrogen atoms by light from these stars.
June's Hubble heritage image is of the emission nebula and HII region known as M20, NGC 6514, and more commonly as the Trifid Nebula. 9,000 light-years from us, M20 lies in the constellation Sagittarius; this image covers approximately 3.
Particle winds from young clusters of stars (often with giant or supergiant HII regions surrounding them) and shock waves created by supernovae inject enormous energy into their surroundings, which leads to hypersonic turbulence.
The image below shows the appearance of a bright supernova (SN1998BU) in one of M96 HII regions in the spring of 1998. It was imaged on May 25, 1998 from Sooke, BC with Cookbook 245 LDC CCD camera on Ultima 8 f6.
The latest SDSS-III image shows details covering a range of scales, from a small part of the sky centred on the galaxy M33 (top left), to the spiral arms of this galaxy (top middle), and the object NGC 604, which is one of the largest HII regions in ...
Technically, they are a type of HII region because the majority of hydrogen will be ionised. However, planetary nebulae are denser and more compact than the emission nebulae in star formation regions.
that the far-infrared luminosity arises from cold (~17-22 K) dust associated with diffuse HI cirrus clouds, 15-30% from cold (~19 K) dust associated with molecular gas, and less than 10% from warm (~29 K) dust in the extended low-density HII regions.
About 70% of these sources matched sources found by the Mount Wilson 2.2 micron survey. Rockets also found bright infrared emission from HII regions (regions of ionized hydrogen) and the center of our galaxy.
 See also: Galaxy, Star, Light, Galaxies, Sun
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