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Apollo Lunar Module. The Apollo Lunar Module ( LM / ˈlɛm / ), originally designated the Lunar Excursion Module ( LEM ), was the lunar lander spacecraft that was flown between lunar orbit and the Moon's surface during the United States' Apollo program. It was the first crewed spacecraft to operate exclusively in the airless vacuum of space ...
A star is a massive luminous spheroid astronomical object made of plasma that is held together by its own gravity.Stars exhibit great diversity in their properties (such as mass, volume, velocity, stage in stellar evolution, and distance from Earth) and some of the outliers are so disproportionate in comparison with the general population that they are considered extreme.
17.88. 13,500-26,000. SIMBAD. [165] Note that even the most luminous stars are much less luminous than the more luminous persistent extragalactic objects, such as quasars. For example, 3C 273 has an average apparent magnitude of 12.8 (when observing with a telescope ), but an absolute magnitude of −26.7.
Limiting magnitude. Visual effect of night sky's brightness. In astronomy, limiting magnitude is the faintest apparent magnitude of a celestial body that is detectable or detected by a given instrument. [1] In some cases, limiting magnitude refers to the upper threshold of detection. In more formal uses, limiting magnitude is specified along ...
Mass–luminosity relation. In astrophysics, the mass–luminosity relation is an equation giving the relationship between a star's mass and its luminosity, first noted by Jakob Karl Ernst Halm. [1] The relationship is represented by the equation: where L⊙ and M⊙ are the luminosity and mass of the Sun and 1 < a < 6. [2]
Stellar structure. Cross-section of the Sun. Stellar structure models describe the internal structure of a star in detail and make predictions about the luminosity, the color and the future evolution of the star. Different classes and ages of stars have different internal structures, reflecting their elemental makeup and energy transport ...
Of those, 103 are main sequence stars: 80 red dwarfs and 23 "typical" stars having greater mass. Additionally, astronomers have found 6 white dwarfs (stars that have exhausted all fusible hydrogen), 21 brown dwarfs, as well as 1 sub-brown dwarf, WISE 0855−0714 (possibly a rogue planet ). The closest system is Alpha Centauri, with Proxima ...
In practice, names are only universally used for the very brightest stars ( Sirius, Arcturus, Vega, etc.) and for a small number of slightly less bright but "interesting" stars ( Algol, Polaris, Mira, etc.). For other naked eye stars, the Bayer or Flamsteed designation is often preferred. In addition to the traditional names, a small number of ...