active region
Credit: A. Title (Stanford Lockheed Institute), TRACE, NASA
A localized volume of the Sun's outer atmosphere where powerful magnetic fields, emerging from subsurface layers, give rise to various short-lived features.
active region--Part of the solar atmosphere that is associated with a magnetic field where solar events often take place.
adiabatic expansion--The expansion and cooling of a gas in which it neither gains or loses energy ...
active region Region of the photosphere of the Sun surrounding a sunspot group, which can erupt violently and unpredictably. During sunspot maximum, the number of active regions is also a maximum.
Active Region (AR). A localized, transient volume of the solar atmosphere in which plages, sunspots, faculae, flares, etc. may be observed.
Angstrom. A unit of length = 1.0E-08cm.
Active Region - A region of the Sun's surface layers that has a large magnetic field and in which sunspots, flares, and prominences preferentially occur ...
active region: An area on the sun where sunspots, prominences, flares, etc., occur.
adaptive optics: Computer-controlled telescope mirrors that can at least partially compensate for seeing.
Active regions on the solar surface are a result of magnetic fields rising from the solar interior and gradually expanding into Sun's outer atmosphere, the corona, in a process known as magnetic flux emergence.
Active region 9393 as seen by the MDI instrument on SOHO hosted the largest sunspot group observed so far during the current solar cycle.
The photoactive region of the CCD is, generally, an epitaxial layer of silicon. It has a doping of p+ (Boron) and is grown upon the substrate material, often p++.
N180B is an active region of star formation in the irregular galaxy, the Large Magellanic Cloud (LMC). This particular region within the LMC contains some of the brightest clusters of stars known to exist.
active region (SOHO Glossary - GSFC) An area of the Sun where the magnetic fields are very strong. At ultraviolet and X-ray wavelengths they appear bright. In visible light they exhibit sunspots.
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For other uses, see Sunspot (disambiguation).
This region (NOAA Active Region AR6659, June 10, 1991) produced some of the most powerful flares ever recorded and remained active over many days.
The part of a solar active region that appears bright when viewed in H0.
Planck constant - (n.) ...
The approximate center of a range of heliographic longitudes in which ACTIVE REGIONS are more numerous and more FLARE-active than the average. ACTIVE PROMINENCE.
Part of the largest sunspot in Active Region 10030 recorded on 15 July 2002 with the Swedish 1-m Solar Telescope on La Palma.
These sites are called active regions, and the surrounding areas, which have smoothly distributed chromospheric emission, are called plages, after the French word for "beach.
Besides sunspots, there exist a great number of tiny spotless dipoles called ephemeral active regions, which last less than a day on average and are found all over the Sun rather than just in the spot latitudes.
Similarly, Borrelly has a series of flat-topped, steep-sided hills in the central area of the comet near the most active regions. Scientists call those features mesas. They may have been formed in the same way mesas are formed on Earth.
Sextans A (UGCA 205) is a dwarf irregular galaxy, approximately 4.31 million light-years distant. It is a very active region of star formation, notable for its unusual square shape. It has a visual magnitude of 11.
X-ray spectrography of solar flares and active regions
S055
Chromospheric and coronal extreme UV photography ...
flare, solar Explosive event occurring in or near an active region on the Sun. [More Info: Field Guide] ...
The inner coma shows a wide range and number of features such as jets and fans, which are most likely related to active regions on the comet nucleus.
The new observations indicate that the burst and the supernova occurred in an active region in one of the galaxy's spiral arms. A very compact source of emission is seen at the exact position of the gamma-ray burst.
In solar astronomy, a plage (pronounced plahzh) is the chromospheric Fraunhofer line emission region above a cluster of faculae. They are associated with sunspots and active regions on the Sun.
The magnetic field gives rise to strong heating in the corona, forming active regions that are the source of intense solar flares and coronal mass ejections. The largest sunspots can be tens of thousands of kilometers across.
ranges of Erymanthus and Cyllene on the south to a narrow strip of fertile land on the north, bordering the Gulf of Corinth, into which the mountain Panachaicus projects....
in the southwest. The gulf is one of the most seismically active regions in ...
The solar wind emanates radially from all parts of the Sun: the fast wind originates from the coronal holes and the quiet Sun, whereas the slow wind arises from the coronal streamers. Active regions, which lie under closed magnetic loops, ...
Magnetic fields about 1-2 gauss over most of its surface; as high as 10-1000 gauss in active regions. If the total angular momentum of the solar system were concentrated in the Sun, its equatorial rotation speed would be about 100 km s-1. [H76] ...
 See also: Solar, Field, Sun, Time, Corona
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