Supposed to move objects light years from Earth 32 62 measured at visual magnitude. The naked eye to see the brightness of celestial bodies, not their true light; the same brightness of celestial objects far from Earth near the earth than from the much darker look. For comparison purposes, the brightness of celestial bodies, astronomical in absolute magnitude as the distinction between standards such as the sun's absolute magnitude is +4 8.
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No. 2
Absolute magnitude of stars on the assumption that the distance between the Earth for 10 seconds (32.6 light years) where the measured star brightness. Different from the apparent magnitude used. It reflects the true celestial light skills. If the absolute magnitude indicated by m, with m as the magnitude that the star into the distance gap between the number of seconds, r, then m = m +5-5 lgr.
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Stars and galaxies in the absolute magnitude M
Stars and galaxies in the measurement of absolute magnitude, the standard distance was _set_ between 10 seconds and about 32.616 light years or 300 trillion miles, then the object's parallax is 0.1. " In the definition of its absolute magnitude, you must specify which type of measurement of electromagnetic radiation. If calculated according to the energy released, and the results will be known as the radiant heat intensity. The lower the star equivalent, on behalf of the brighter objects. Absolute magnitude and apparent magnitude, parallax can be (distance) conversion. As distance reasons, many stars absolute magnitude lower than its apparent magnitude (bright) many; and some stars due to the reasons from our closer, and its absolute magnitude becomes large (dark) a lot.
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Calculations
If the known objects in the apparent magnitude m and distance d, then you can draw the following formula objects absolute magnitude M: Or Which, for 10 seconds difference, that is 32.616 light years, is the object of the parallax is 0.1 arc seconds. If the known objects in the absolute magnitude M, and distance d, then you can draw the following formula, as the magnitude of celestial bodies m: Or 【Example】 Rigel apparent magnitude of +0.18, distance 773 light years, its absolute magnitude: M Rigel = 0.18 + 5 * log10 (32.616/773) = -6.7 Vega's parallax as 0.133 ", depending on the magnitude of +0.03, then its absolute magnitude: M Vega = 0.03 + 5 * (1 + log10 (0.133)) = +0.65 Alpha Centauri parallax 0.750 ", the absolute magnitude of +4.37, then its apparent magnitude is: m South Gate II = 4.37 - 5 * (1 + log10 (0.750)) = -0.01
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Planet of the absolute magnitude H
行星的绝对星等H
For the planets, comets, asteroids and other non-stellar objects, the absolute magnitude of their definition is completely different. The definition of the absolute magnitude of stars does not apply. At this point, the absolute magnitude is defined as the object in the distance from the Sun and the Earth as an astronomical unit is (au), and the phase angle of 0 °, showing the apparent magnitude. This is actually impossible, just for convenience of calculation. Calculation Absolute magnitude H: Where is the sun's apparent magnitude (-26.73), is a geometric object surface albedo (between 0 and 1), is the object radius, is an astronomical unit. 【Example】 Moon: = 0.12, = 3476 / 2 km = 1738 km
