faculae

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Related to faculae: Facular

photosphere

photosphere, luminous, apparently opaque layer of gases that forms the visible surface of the sun or any other star. The photosphere lies between the dense interior gases and the more attenuated gases of the chromosphere. The incandescent gases of the photosphere, estimated to be at temperatures near 6,000K, are so much brighter than the other layers of the sun that they seem to form a surface. These gases are in a constant state of agitation due to convection currents that reach down to 150,000 mi (241,000 km) below the photosphere. Differences in the density of the gases result in a grainy appearance of the photosphere; the small bright patches, or granules, are several hundred miles in diameter and are constantly shifting. Another feature of the photosphere, observed only near the sun's edge, is the appearance near sunspots of bright, veinlike regions known as faculae.

faculae

(fak -yŭ-lee) (singular: facula)

1. Bright patches in the upper part of the solar photosphere that have a higher temperature than their surroundings and occur in areas where there is an enhancement of the relatively weak vertical magnetic field. With the exception of polar faculae, which consist of isolated granules and appear in high heliographic latitudes around the minimum of the sunspot cycle, they are intimately related to sunspots, forming shortly before the spots – in the same vicinity – and persisting for several weeks after their disappearance. Faculae are best seen when near the Sun's limb, where limb darkening renders them more readily visible. They are approximately coincident, albeit at a lower level, with the plages visible in monochromatic light.

2. Bright patches observed on the surface of planetary satellites, especially Ganymede.

Collins Dictionary of Astronomy © Market House Books Ltd, 2006

References in periodicals archive ?

The emissivity of faculae as they approach the solar limb [135] cannot be reasonably explained within the context of the gaseous models.

Forty lines of evidence for condensed matter--the sun on trial: liquid metallic hydrogen as a solar building block

Changes to the disk-integrated solar irradiance at any time are thus the net of the competing emission enhancements in all bright faculae (and plage) and emission reduction in all dark sunspots.

A solar irradiance climate data record

As seen in [section]2.3.5, strong fields can be observed in faculae and magnetic bright points, while weak fields are present above the granules ([section]2.3.4) and in coronal structures ([section] 2.3.8).

Forty lines of evidence for condensed matter--the sun on trial: liquid metallic hydrogen as a solar building block

AR1530 S19/210[degrees] rounded the SE limb on July 23, a single Hsx sunspot displaying the Wilson effect and amidst an area of faculae. The group was still a single penumbral sunspot on July 25 but developed a small follower by July 27.

Solar section

When sunspots and faculae all but disappeared during the low part of the last solar cycle, total solar radiation dropped by only 0.1 percent.

A star in the greenhouse; can the sun dampen the predicted global warming?

AR1087 N19[degrees]/334[degrees] appeared on the eastern limb on July 9 type Axx which rapidly developed to type Dso by July 10, surrounded by a large area of faculae. On the following day, small spots could be determined between the leader and follower spots with a total area estimated around 140 millionths.

Solar section

Traditional white-light filters transmit less than 0.0032% of the Sun's energy, revealing in great detail dark sunspots and their surrounding penumbras as well as bright faculae in the photosphere.

Catch the nearest star: the Sun provides astrophotographers with a captivating target every clear day

AR1082 N29[degrees]/300[degrees] rounded the eastern limb as a bright region of faculae with a small forming sunspot on June 15.

Solar section

All structural features associated with solar activity (sunspots, faculae, prominences, flares, spicules, etc ...) tend to be explained using magnetic fields, as the only means to impart structural features to a gaseous entity which, in reality, can support none.

Magnetic fields and directional spectral emissivity in sunspots and faculae: complimentary evidence of metallic behavior on the surface of the sun

Between some of the Alaska-size convection cells ("granulation") are tiny, bright walls that, when seen sideon near the limb, form bright faculae.

Big Bear's big new eye

The group then slowly declined and was observed on Feb 17 as two Axx spots approaching the western limb and later that day as just a patch of faculae.

Solar section

The faculae, on the contrary, they suppose due to volcanic eruptions from the liquified mass.

A thermodynamic history of the solar constitution--I: the journey to a gaseous sun