Search results
Results from the WOW.Com Content Network
A molecular cloud—sometimes called a stellar nursery if star formation is occurring within—is a type of interstellar cloud of which the density and size permit absorption nebulae, the formation of molecules (most commonly molecular hydrogen, H 2), and the formation of H II regions.
This glossary of astronomy is a list of definitions of terms and concepts relevant to astronomy and cosmology, their sub-disciplines, and related fields. Astronomy is concerned with the study of celestial objects and phenomena that originate outside the atmosphere of Earth. The field of astronomy features an extensive vocabulary and a ...
By definition, these clouds must have a v lsr greater than 90 km s −1, where v lsr is the local standard rest velocity. They are detected primarily in the 21 cm line of neutral hydrogen, [6] and typically have a lower portion of heavy elements than is normal for interstellar clouds in the Milky Way.
The following tables list molecules that have been detected in the interstellar medium or circumstellar matter, grouped by the number of component atoms. Neutral molecules and their molecular ions are listed in separate columns; if there is no entry in the molecule column, only the ionized form has been detected. Designations (names of ...
About half the total mass of the Milky Way's galactic ISM is found in molecular clouds [9] and the galaxy includes an estimated 6,000 molecular clouds, each with more than 100,000 M ☉. [10] The nebula nearest to the Sun where massive stars are being formed is the Orion Nebula, 1,300 light-years (1.2 × 10 16 km) away. [11]
MONS – (telescope) Measuring Oscillations in Nearby Stars, a Danish space telescope that was proposed and designed but not built [6] MOST – (telescope) Microvariability and Oscillations of STars, a space telescope designed to detect oscillations in the atmospheres of stars and extrasolar planetss in orbit around other stars
Star-forming regions are a class of emission nebula associated with giant molecular clouds. These form as a molecular cloud collapses under its own weight, producing stars. Massive stars may form in the center, and their ultraviolet radiation ionizes the surrounding gas, making it visible at optical wavelengths.
A dark nebula or absorption nebula is a type of interstellar cloud, particularly molecular clouds, that is so dense that it obscures the visible wavelengths of light from objects behind it, such as background stars and emission or reflection nebulae.