Classification of stars

Question 1

Define the brightness of a star

Answer 1

its a measure of how much visible light from the star reaches our eyes

Question 2

define the luminosity of a star

Answer 2

its the energy it emits per second, in all wavelength

Question 3

define the apparent magnitude

Answer 3

its a measure of its brightness as it appears in the sky from earth

Question 4

what is the symbol for apparent magnitude

Answer 4

m

Question 5

what is the symbol for absolute magnitude

Answer 5

M

Question 6

what is the definition for absolute magnitude

Answer 6

the apparent magnitude the star would have if it were 10pc away

Question 7

how many times brighter is a first-magnitude star than a sixth-magnitude star (pogson’s ratio)

Answer 7

100 times brighter

Question 8

What is the Hipparcos scale

Answer 8

magnitude 1 = brightest star visible to unaided eye

magnitude 6 = dimmest star visible to unaided eye

Question 9

how is the parsec defined

Answer 9

its defined by a method of measuring distance called trigonometric parallax

Question 10

what is the equation for finding the parallax angle

Answer 10

tan α = d/D
α = parallax angle
d = mean earth-sun distance
D = sun-star-distance

Question 11

what is the limit on distance for trigonometric parallax

Answer 11

150 ly from earth as the smaller the parallax the greater the uncertainty in the measurement