Stellar quantities

Question 1

Interstellar space

Answer 1

Space between two stars

Question 2

Stellar cluster

Answer 2

Group of stars that attract each other gravitationally & are close

Question 3

Galaxy

Answer 3

Very large no. of stars and stellar clusters

Question 4

Intergalactic space

Answer 4

Space between galaxies

Question 5

Superclusters

Answer 5

A very large collection of galaxies

Question 6

Light year

Answer 6

Distance light travels in a year

Question 7

Astronomical unit (AU)

Answer 7

Average distance between earth and sun

Question 8

Parsec

Answer 8

Distance at which 1 AU substends an angle of 1 arcsecond (1/3600 degrees)

Question 9

How is stellar parallax used to find the distance to a star?

Answer 9

Measure the star’s angular position once, then measure again six months later. This gives the parallax angle

Stellar parallax: Apparent displacement of star relative to fixed background

Question 10

When does stellar parallax fail?

Answer 10

When the parallax angle cannot be measured due to very large distance

Question 11

Luminosity

Answer 11

Total power radiated by star

Question 12

Assumption made of stars in calculations?

Answer 12

They are black bodies

Question 13

Apparent brightness

Answer 13

power received per unit area on body