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The core of the Sun is considered to extend from the center to about 0.2 of the solar radius (139,000 km; 86,000 mi). [1] It is the hottest part of the Sun and of the Solar System. It has a density of 150,000 kg/m 3 (150 g/cm 3) at the center, and a temperature of 15 million kelvins (15 million degrees Celsius; 27 million degrees Fahrenheit). [2]
A nebula that is visible to the human eye from Earth would appear larger, but no brighter, from close by. [6] The Orion Nebula, the brightest nebula in the sky and occupying an area twice the angular diameter of the full Moon, can be viewed with the naked eye but was missed by early astronomers. [7]
The nebula was imaged by the Hubble Space Telescope in the 1990s. The primary component of the central binary is the hot core of a star that reached the end of its main-sequence life cycle, ejected most of its outer layers and became a red giant, and is now contracting into a white dwarf. It is believed to have been a sun-like star early in its ...
NGC 7027 has a rich and highly ionized spectrum caused by its hot central star. [7] The progenitor star of NGC 7027 is believed to have been about 3 to 4 times the mass of the Sun before the nebula was formed. [7] It is possible that the central white dwarf of NGC 7027 has an accretion disk that acts as a source of high temperatures. [24]
NGC 2440 is a planetary nebula, one of many in our galaxy. Its central star, HD 62166, [1] is possibly the hottest known white dwarf, about 400,000°F(200,000°C). The nebula is situated in the constellation Puppis. It was discovered by William Herschel on March 4, 1790. He described it as "a beautiful planetary nebula of a considerable degree ...
A corona (pl.: coronas or coronae) is the outermost layer of a star's atmosphere. It is a hot but relatively dim region of plasma populated by intermittent coronal structures known as solar prominences or filaments. The Sun's corona lies above the chromosphere and extends millions of kilometres into outer
The Sun is the star at the center of the Solar System.It is a massive, nearly perfect sphere of hot plasma, heated to incandescence by nuclear fusion reactions in its core, radiating the energy from its surface mainly as visible light and infrared radiation with 10% at ultraviolet energies.
R136a1 has a surface temperature of around 46,000 K (45,700 °C; 82,300 °F), eight times as hot as the Sun, and with peak radiation in the extreme ultraviolet. [ 4 ] R136a1 has a B–V index of about 0.03, which is a typical colour for an F-type star .