# Astronomy college course/Introduction to stellar measurements/questions

## AstroStellarMeasurements_Study

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### AstroStellarMeasurements_Study-v1s1

1. Stellar parallax is

___ a) a numerical measure of brightness as seen from Earth
___ b) a numerical measure of brightness as seen from a distance of approximately 33 light-years
___ c) an annual change in angular position of a star as seen from Earth
___ d) an astronomical object with known luminosity.
___ e) the total amount of energy emitted per unit time.

2. Luminosity is

___ a) an annual change in angular position of a star as seen from Earth
___ b) a numerical measure of brightness as seen from Earth
___ c) a numerical measure of brightness as seen from a distance of approximately 33 light-years
___ d) an astronomical object with known luminosity.
___ e) the total amount of energy emitted per unit time.

3. A standard candle is

___ a) a numerical measure of brightness as seen from a distance of approximately 33 light-years
___ b) a numerical measure of brightness as seen from Earth
___ c) an astronomical object with known luminosity.
___ d) an annual change in angular position of a star as seen from Earth
___ e) the total amount of energy emitted per unit time.

4. Absolute magnitude is

___ a) a numerical measure of brightness as seen from Earth
___ b) the total amount of energy emitted per unit time.
___ c) an annual change in angular position of a star as seen from Earth
___ d) an astronomical object with known luminosity.
___ e) a numerical measure of brightness as seen from a distance of approximately 33 light-years

5. Relative magnitude is

___ a) a numerical measure of brightness as seen from Earth
___ b) a numerical measure of brightness as seen from a distance of approximately 33 light-years
___ c) an astronomical object with known luminosity.
___ d) an annual change in angular position of a star as seen from Earth
___ e) the total amount of energy emitted per unit time.

6. In 1989 the satellite Hipparcos was launched primarily for obtaining parallaxes and proper motions allowing measurements of stellar parallax for stars up to about 500 parsecs away, which is about ____ times the diameter of the Milky Way Galaxy.

___ a) 15
___ b) 1.5
___ c) 150
___ d) .015
___ e) 0.15

7. An object emits thermal (blackbody) radiation with a peak wavelength of 250nm. How does its temperature compare with the Sun?

___ a) 5 times colder than the Sun
___ b) 2 times colder than the Sun
___ c) 5 times hotter than the Sun
___ d) The temperature is the same
___ e) 2 times hotter than the Sun

8. The "normalized intensity" of a Sun-like star situated one parsec from Earth would be 4πI = 1. What is 4πI for a star with 100 times the Sun's energy output that is situated 10pc from Earth?

___ a) 10-2
___ b) 10-3
___ c) 10-1
___ d) 1
___ e) 10-4

9. An orbiting satellite makes a circular orbit 5 AU from the Sun. It measures a parallax angle of 0.2 of an arcsecond (each way from the average position). What is the star's distance?

___ a) 25 parsecs
___ b) 5 parsecs
___ c) 50 parsecs
___ d) 1 parsec
___ e) 10 parsecs

10. A star that is increasing it's temperature while maintaining constant luminosity is

___ a) getting smaller in size
___ b) on the verge of becoming a supernovae
___ c)e) getting larger in size
___ d) in the process of dying
___ e) turning red

11. The range of wavelength for visible light is between

___ a) 5000 and 6000 nanometers
___ b) 1 and 10 nanometers
___ c) 600 and 1200 nanometers
___ d) 400 and 700 nanometers
___ e) 0.1 and 10 nanometers

12. Based on the HR diagrams and images in stars shown in the materials, a very large red supergiant has a diameter that is about ____ greater than a small white dwarf.

___ a) 3x107
___ b) 3x109
___ c) 3x105
___ d) 3x1011
___ e) 3x103

#### Key to AstroStellarMeasurements_Study-v1s1

1. Stellar parallax is

- a) a numerical measure of brightness as seen from Earth
- b) a numerical measure of brightness as seen from a distance of approximately 33 light-years
+ c) an annual change in angular position of a star as seen from Earth
- d) an astronomical object with known luminosity.
- e) the total amount of energy emitted per unit time.

2. Luminosity is

- a) an annual change in angular position of a star as seen from Earth
- b) a numerical measure of brightness as seen from Earth
- c) a numerical measure of brightness as seen from a distance of approximately 33 light-years
- d) an astronomical object with known luminosity.
+ e) the total amount of energy emitted per unit time.

3. A standard candle is

- a) a numerical measure of brightness as seen from a distance of approximately 33 light-years
- b) a numerical measure of brightness as seen from Earth
+ c) an astronomical object with known luminosity.
- d) an annual change in angular position of a star as seen from Earth
- e) the total amount of energy emitted per unit time.

4. Absolute magnitude is

- a) a numerical measure of brightness as seen from Earth
- b) the total amount of energy emitted per unit time.
- c) an annual change in angular position of a star as seen from Earth
- d) an astronomical object with known luminosity.
+ e) a numerical measure of brightness as seen from a distance of approximately 33 light-years

5. Relative magnitude is

+ a) a numerical measure of brightness as seen from Earth
- b) a numerical measure of brightness as seen from a distance of approximately 33 light-years
- c) an astronomical object with known luminosity.
- d) an annual change in angular position of a star as seen from Earth
- e) the total amount of energy emitted per unit time.

6. In 1989 the satellite Hipparcos was launched primarily for obtaining parallaxes and proper motions allowing measurements of stellar parallax for stars up to about 500 parsecs away, which is about ____ times the diameter of the Milky Way Galaxy.

- a) 15
- b) 1.5
- c) 150
+ d) .015
- e) 0.15

7. An object emits thermal (blackbody) radiation with a peak wavelength of 250nm. How does its temperature compare with the Sun?

- a) 5 times colder than the Sun
- b) 2 times colder than the Sun
- c) 5 times hotter than the Sun
- d) The temperature is the same
+ e) 2 times hotter than the Sun

8. The "normalized intensity" of a Sun-like star situated one parsec from Earth would be 4πI = 1. What is 4πI for a star with 100 times the Sun's energy output that is situated 10pc from Earth?

- a) 10-2
- b) 10-3
- c) 10-1
+ d) 1
- e) 10-4

9. An orbiting satellite makes a circular orbit 5 AU from the Sun. It measures a parallax angle of 0.2 of an arcsecond (each way from the average position). What is the star's distance?

+ a) 25 parsecs
- b) 5 parsecs
- c) 50 parsecs
- d) 1 parsec
- e) 10 parsecs

10. A star that is increasing it's temperature while maintaining constant luminosity is

+ a) getting smaller in size
- b) on the verge of becoming a supernovae
- c)e) getting larger in size
- d) in the process of dying
- e) turning red

11. The range of wavelength for visible light is between

- a) 5000 and 6000 nanometers
- b) 1 and 10 nanometers
- c) 600 and 1200 nanometers
+ d) 400 and 700 nanometers
- e) 0.1 and 10 nanometers

12. Based on the HR diagrams and images in stars shown in the materials, a very large red supergiant has a diameter that is about ____ greater than a small white dwarf.

- a) 3x107
- b) 3x109
+ c) 3x105
- d) 3x1011
- e) 3x103