ASTA02H3 Lecture Notes - Photon, Black-Body Radiation, Sirius
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Astronomy - Session 2
apparent visual magnitude
describes how stars look to human eyes
the brightness of stars is measured using the magnitude scale
ancient astronomers divided the stars into six magnitudes
mv= apparent visual magnitude
a star may have negative or positive magnitude
Q. what is the name of the star that serves as the zero of the magnitude scale?
Q. what is brighter, a -1 star or a +3.5 star?
A. a -1 mv star is brighter than a +3.5
Vega was the northern star
distance is measured through ground-based parallax measurements
its spectrum was amongst the first to be measured
Q. the mv of a number of stars is given- sort them in order of descending brightness
a) Proxinma Centauri, +11.05
b) Betelgeuse, 0.42
c) Antares, +0.96
d) Dubje, +1.79
e) Sirius A, -1.46
f) Sirius B, +8.49
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