AST1002 Exam 3 With
Correct Answers
Apparent Magnitude (m) - ANSWER How bright an object appears to be to
an observer. If the change in magnitude (Δ M) is 1, then the difference in
brightness is 2.512.
Absolute Magnitude - ANSWER The magnitude a star would be if it were
exactly 10 parsecs away
Formula for change in magnitude (general) - ANSWER Δ B = (2.512)^(Δ M)
Formula for absolute magnitude - ANSWER M = m - 5log(d)+5 ; d is for
distance in parsecs
Sun's apparent magnitude from Earth is _______. - ANSWER Apparent
magnitude = -26.5.
Sun's absolute magnitude from Earth is ______. - ANSWER Absolute
magnitude = +4.8
, Stellar Parallax is ________. - ANSWER The distance d (in parsecs) = 1/parallax
angle in arc seconds
The closest other star is ________. - ANSWER Proxima Centauri (20 parsecs)
Luminosity - ANSWER The energy output per unit time
Colour Indices: U-B Colour Index and B-V Colour Index - ANSWER
(U-B=mu-mv); (B-V=mb-mv)
U-B Colour Index - ANSWER measures the amount of ultraviolet light relative
to the amount of blue light emitted by a star
B-V Colour Index - ANSWER A graph of B-V vs temperature allows one to
determine the temperature of a star
Spectral Types - ANSWER Was first classified as "A through Q" but then
changed to OBAFGKM (O is hot, M is cold)
Strengths of Absorption lines - ANSWER
Correct Answers
Apparent Magnitude (m) - ANSWER How bright an object appears to be to
an observer. If the change in magnitude (Δ M) is 1, then the difference in
brightness is 2.512.
Absolute Magnitude - ANSWER The magnitude a star would be if it were
exactly 10 parsecs away
Formula for change in magnitude (general) - ANSWER Δ B = (2.512)^(Δ M)
Formula for absolute magnitude - ANSWER M = m - 5log(d)+5 ; d is for
distance in parsecs
Sun's apparent magnitude from Earth is _______. - ANSWER Apparent
magnitude = -26.5.
Sun's absolute magnitude from Earth is ______. - ANSWER Absolute
magnitude = +4.8
, Stellar Parallax is ________. - ANSWER The distance d (in parsecs) = 1/parallax
angle in arc seconds
The closest other star is ________. - ANSWER Proxima Centauri (20 parsecs)
Luminosity - ANSWER The energy output per unit time
Colour Indices: U-B Colour Index and B-V Colour Index - ANSWER
(U-B=mu-mv); (B-V=mb-mv)
U-B Colour Index - ANSWER measures the amount of ultraviolet light relative
to the amount of blue light emitted by a star
B-V Colour Index - ANSWER A graph of B-V vs temperature allows one to
determine the temperature of a star
Spectral Types - ANSWER Was first classified as "A through Q" but then
changed to OBAFGKM (O is hot, M is cold)
Strengths of Absorption lines - ANSWER
