Stars

Question 1

Parallax

Answer 1

Allows us to detect nearby stars because their position is affected by the solar positioning

Question 2

Parallax angle

Answer 2

Angle subtended by a star by a line between the Earth and the Sun
d = R/angle

Question 3

1 parsec

Answer 3

Distance to a star which subtends an angle of 1 arcsecond

Question 4

Absolute magnitude

Answer 4

Apparent magnitude if 10 parsecs away, M

Question 5

Black body

Answer 5

Perfect absorber of radiation, emits continuous spectrum

Question 6

Balmer lines

Answer 6

Absorption lines from the photosphere by gases absorbing certain photons

Question 7

Apparent magnitude

Answer 7

Measure of brightness of a star, m

Question 8

Scale used to measure a star’s luminosity

Answer 8

Hipparcos scale

Question 9

How did the Hipparcos scale value the brightness of visible stars?

Answer 9

6 dimmest to 1 brightest

Subjective

Question 10

What is the relation between brightness and apparent magnitude?

Answer 10

1 on the scale is an intensity ratio of 2.51

Question 11

Light year

Answer 11

Distance light travels in 1 year

Question 12

Astronomical unit (AU)

Answer 12

Distance from Earth to the centre of the Sun

Question 13

Arc second

Answer 13

1°/3600

Question 14

Example of a black body;

Answer 14

Stars

Question 15

Wien’s law used to find…

Answer 15

The wavelength at peak intensity

Question 16

Photosphere meaning

Answer 16

Outer layer of a star

Question 17

Stefan’s law finds

Answer 17

The power output (luminosity) of a star from surface area and tenperature

Question 18

Relationship between absolute magnitude and power output

Answer 18

Equal

Question 19

Inverse square law for stars;

Answer 19

Brightness ∝ 1/d²

Question 20

What state are atoms in stars that produce Balmer lines?

Answer 20

n = 2