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The bolometric correction scale is set by the absolute magnitude of the Sun and an adopted (arbitrary) absolute bolometric magnitude for the Sun.Hence, while the absolute magnitude of the Sun in different filters is a physical and not arbitrary quantity, the absolute bolometric magnitude of the Sun is arbitrary, and so the zero-point of the bolometric correction scale that follows from it.
M bol,⊙ is the bolometric magnitude of the Sun; M bol,★ is the bolometric magnitude of the star. In August 2015, the International Astronomical Union passed Resolution B2 [9] defining the zero points of the absolute and apparent bolometric magnitude scales in SI units for power and irradiance (W/m 2), respectively. Although bolometric ...
The zero point of the apparent bolometric magnitude scale is based on the definition that an apparent bolometric magnitude of 0 mag is equivalent to a received irradiance of 2.518×10 −8 watts per square metre (W·m −2).
A more complex definition of absolute magnitude is used for planets and small Solar System bodies, based on its brightness at one astronomical unit from the observer and the Sun. The Sun has an apparent magnitude of −27 and Sirius, the brightest visible star in the night sky, −1.46. Venus at its brightest is -5.
The apparent magnitude is the observed visible brightness from Earth which depends on the distance of the object. The absolute magnitude is the apparent magnitude at a distance of 10 pc (3.1 × 10 17 m), therefore the bolometric absolute magnitude is a logarithmic measure of the bolometric luminosity.
The Sun is 1.4 million kilometers (4.643 light-seconds) wide, about 109 times wider than Earth, or four times the Lunar distance, and contains 99.86% of all Solar System mass. The Sun is a G-type main-sequence star that makes up about 99.86% of the mass of the Solar System. [26]
Conceptual schematic of a bolometer.Power, P, from an incident signal is absorbed and heats up a thermal mass with heat capacity, C, and temperature, T.The thermal mass is connected to a reservoir of constant temperature through a link with thermal conductance, G.
The greater a star's luminosity, the greater its mass will be. The absolute magnitude or luminosity of a star can be found by knowing the distance to it and its apparent magnitude. The stars bolometric magnitude is plotted against its mass, in units of the Sun's mass. This is determined through observation and then the mass of the star is read ...