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  2. Stellar classification - Wikipedia

    en.wikipedia.org/wiki/Stellar_classification

    The spectral type is formed by the letter S and a number between zero and ten. This number corresponds to the temperature of the star and approximately follows the temperature scale used for class M giants. The most common types are S3 to S5. The non-standard designation S10 has only been used for the star Chi Cygni when at an extreme minimum.

  3. Magnitude (astronomy) - Wikipedia

    en.wikipedia.org/wiki/Magnitude_(astronomy)

    Consequently, a magnitude 1 star is about 2.5 times brighter than a magnitude 2 star, about 2.5 2 times brighter than a magnitude 3 star, about 2.5 3 times brighter than a magnitude 4 star, and so on. This is the modern magnitude system, which measures the brightness, not the apparent size, of stars.

  4. Apparent magnitude - Wikipedia

    en.wikipedia.org/wiki/Apparent_magnitude

    4.92: planet Venus: seen from Earth maximum brightness [42] when illuminated as a crescent −4.14: planet Venus: seen from Earth mean brightness [42] −4: Faintest objects observable during the day with naked eye when Sun is high. An astronomical object casts human-visible shadows when its apparent magnitude is equal to or lower than −4 ...

  5. Astronomical spectroscopy - Wikipedia

    en.wikipedia.org/wiki/Astronomical_spectroscopy

    The Star-Spectroscope of the Lick Observatory in 1898. Designed by James Keeler and constructed by John Brashear.. Astronomical spectroscopy is the study of astronomy using the techniques of spectroscopy to measure the spectrum of electromagnetic radiation, including visible light, ultraviolet, X-ray, infrared and radio waves that radiate from stars and other celestial objects.

  6. Stellar designations and names - Wikipedia

    en.wikipedia.org/wiki/Stellar_designations_and_names

    The Bright Star Catalogue, which is a star catalogue listing all stars of apparent magnitude 6.5 or brighter, or roughly every star visible to the naked eye from Earth, contains 9,096 stars. [1] The most voluminous modern catalogues list on the order of a billion stars, out of an estimated total of 200 to 400 billion in the Milky Way .

  7. Astronomical naming conventions - Wikipedia

    en.wikipedia.org/wiki/Astronomical_naming...

    The WGSN's first bulletin of July 2016 [5] included a table of the first two batches of names approved by the WGSN (on 30 June and 20 July 2016) together with names of stars adopted by the IAU Executive Committee Working Group on Public Naming of Planets and Planetary Satellites during the 2015 NameExoWorlds campaign [6] and recognized by the ...

  8. You’ll Be Able to See 6 Planets in the Sky This Week ... - AOL

    www.aol.com/ll-able-see-6-planets-210511810.html

    As Star Walk states, it can be tricky to look at the sky and mistake stars for planets. If the object you’re looking at in the sky twinkles, it’s a star. If the object you’re looking at in ...

  9. Glossary of astronomy - Wikipedia

    en.wikipedia.org/wiki/Glossary_of_astronomy

    A-type star In the Harvard spectral classification system, a class of main-sequence star having spectra dominated by Balmer absorption lines of hydrogen. Stars of spectral class A are typically blue-white or white in color, measure between 1.4 and 2.1 times the mass of the Sun, and have surface temperatures of 7,600–10,000 kelvin.