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- https://phys.libretexts.org/Bookshelves/Astronomy__Cosmology/Supplemental_Modules_(Astronomy_and_Cosmology)/Cosmology/Astrophysics_(Richmond)/06%3A_Blackbody_RadiationAt the turn of the twentieth century, German physicist Max Planck figured out a mathematical expression for the spectrum of radiation emitted from a blackbody, a (fictional) object which absorbs all i...At the turn of the twentieth century, German physicist Max Planck figured out a mathematical expression for the spectrum of radiation emitted from a blackbody, a (fictional) object which absorbs all incident radiation.
- https://phys.libretexts.org/Courses/University_of_California_Davis/Physics_156%3A_A_Cosmology_Workbook/01%3A_Workbook/1.15%3A_Distance_and_MagnitudeThere are a bewildering array of different kinds of distances in cosmology. We catalog them here as a resource for you as needed. We also introduce and define other related astronomical technical term...There are a bewildering array of different kinds of distances in cosmology. We catalog them here as a resource for you as needed. We also introduce and define other related astronomical technical terms: apparent and absolute magnitudes.
- https://phys.libretexts.org/Courses/Grossmont_College/ASTR_110%3A_Astronomy_(Fitzgerald)/10%3A_Nature_of_Stars/10.01%3A_The_Brightness_of_StarsThe total energy emitted per second by a star is called its luminosity. How bright a star looks from the perspective of Earth is its apparent brightness. The apparent brightness of a star depends on b...The total energy emitted per second by a star is called its luminosity. How bright a star looks from the perspective of Earth is its apparent brightness. The apparent brightness of a star depends on both its luminosity and its distance from Earth. Thus, the determination of apparent brightness and measurement of the distance to a star provide enough information to calculate its luminosity.
- https://phys.libretexts.org/Bookshelves/Astronomy__Cosmology/Astronomy_1e_(OpenStax)/17%3A_Analyzing_Starlight/17.01%3A_The_Brightness_of_StarsThe total energy emitted per second by a star is called its luminosity. How bright a star looks from the perspective of Earth is its apparent brightness. The apparent brightness of a star depends on b...The total energy emitted per second by a star is called its luminosity. How bright a star looks from the perspective of Earth is its apparent brightness. The apparent brightness of a star depends on both its luminosity and its distance from Earth. Thus, the determination of apparent brightness and measurement of the distance to a star provide enough information to calculate its luminosity.
- https://phys.libretexts.org/Bookshelves/Astronomy__Cosmology/Astronomy_2e_(OpenStax)/17%3A_Analyzing_Starlight/17.02%3A_The_Brightness_of_StarsThe total energy emitted per second by a star is called its luminosity. How bright a star looks from the perspective of Earth is its apparent brightness. The apparent brightness of a star depends on b...The total energy emitted per second by a star is called its luminosity. How bright a star looks from the perspective of Earth is its apparent brightness. The apparent brightness of a star depends on both its luminosity and its distance from Earth. Thus, the determination of apparent brightness and measurement of the distance to a star provide enough information to calculate its luminosity.
- https://phys.libretexts.org/Bookshelves/Astronomy__Cosmology/Stellar_Atmospheres_(Tatum)/04%3A_Flux_Specific_Intensity_and_other_Astrophysical_Terms/4.02%3A_LuminosityWhat we have hitherto called the "radiant flux" \(\Phi\) of a source of radiation, expressed in watts, is generally called by astronomers, when describing the radiant flux from an entire star, the lum...What we have hitherto called the "radiant flux" \(\Phi\) of a source of radiation, expressed in watts, is generally called by astronomers, when describing the radiant flux from an entire star, the luminosity of the star, and the symbol used is \(L\). While this can be expressed in watts, it is commonly expressed in units of the luminosity of the Sun, which is \(3.85 \times 10^{26} \text{watts}\).
- https://phys.libretexts.org/Bookshelves/Astronomy__Cosmology/Big_Ideas_in_Cosmology_(Coble_et_al.)/06%3A_Measuring_Cosmic_Distances/6.03%3A_Standard_CandleWhere the line meets your chosen distance modulus you can read the corresponding distance by scanning horizontally over to find the value for distance on the vertical axis: The green line gives the di...Where the line meets your chosen distance modulus you can read the corresponding distance by scanning horizontally over to find the value for distance on the vertical axis: The green line gives the distance in parsecs, the blue line gives it in kiloparsecs and the red line gives the distance in megaparsecs.