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  2. Period-luminosity relation - Wikipedia

    en.wikipedia.org/wiki/Period-luminosity_relation

    In astronomy, a period-luminosity relation is a relationship linking the luminosity of pulsating variable stars with their pulsation period. The best-known relation is the direct proportionality law holding for Classical Cepheid variables , sometimes called the Leavitt Law .

  3. Classical Cepheid variable - Wikipedia

    en.wikipedia.org/wiki/Classical_Cepheid_variable

    A classical Cepheid's luminosity is directly related to its period of variation. The longer the pulsation period, the more luminous the star. The period-luminosity relation for classical Cepheids was discovered in 1908 by Henrietta Swan Leavitt in an investigation of thousands of variable stars in the Magellanic Clouds. [23]

  4. Category:Units of photometry - Wikipedia

    en.wikipedia.org/wiki/Category:Units_of_photometry

    Luminous efficacy (of radiation) K: lumen per watt: lm/W: M −1 ⋅L −2 ⋅T 3 ⋅J: Ratio of luminous flux to radiant flux: Luminous efficacy (of a source) η [nb 3] lumen per watt: lm/W: M −1 ⋅L −2 ⋅T 3 ⋅J: Ratio of luminous flux to power consumption Luminous efficiency, luminous coefficient V: 1: Luminous efficacy normalized by ...

  5. List of physical quantities - Wikipedia

    en.wikipedia.org/wiki/List_of_physical_quantities

    Luminous flux (or luminous power) F: Perceived power of a light source lumen (lm = cd⋅sr) J: Mach number (or mach) M: Ratio of flow velocity to the local speed of sound unitless: 1: Magnetic flux: Φ: Measure of magnetism, taking account of the strength and the extent of a magnetic field: weber (Wb) L 2 M T −2 I −1: scalar Mass fraction: x

  6. Photometry (optics) - Wikipedia

    en.wikipedia.org/wiki/Photometry_(optics)

    Luminous efficacy (of radiation) K: lumen per watt: lm/W: M −1 ⋅L −2 ⋅T 3 ⋅J: Ratio of luminous flux to radiant flux: Luminous efficacy (of a source) η [nb 3] lumen per watt: lm/W: M −1 ⋅L −2 ⋅T 3 ⋅J: Ratio of luminous flux to power consumption Luminous efficiency, luminous coefficient V: 1: Luminous efficacy normalized by ...

  7. Luminance - Wikipedia

    en.wikipedia.org/wiki/Luminance

    Luminous efficacy (of radiation) K: lumen per watt: lm/W: M −1 ⋅L −2 ⋅T 3 ⋅J: Ratio of luminous flux to radiant flux: Luminous efficacy (of a source) η [nb 3] lumen per watt: lm/W: M −1 ⋅L −2 ⋅T 3 ⋅J: Ratio of luminous flux to power consumption Luminous efficiency, luminous coefficient V: 1: Luminous efficacy normalized by ...

  8. HR Carinae - Wikipedia

    en.wikipedia.org/wiki/HR_Carinae

    HR Carinae is a lot like Eta Carinae, both luminous blue variables, and both surrounded by ejected material. HR Carinae is also likely to be a binary system with a similar separation, period, and ratio of component sizes to Eta Carinae. [22] However, the Eta Carinae system is more massive and more luminous.

  9. S Sagittae - Wikipedia

    en.wikipedia.org/wiki/S_Sagittae

    It is around six or seven times as massive and five thousand times as luminous as the Sun and is located around 2,000 light-years away from Earth. [2] Its radius is 58.5 times that of the Sun. [7] The radius, temperature, luminosity, and colour are all variable as the star pulsates during its eight-day period. The period is slowly increasing. [2]