Question 1

The total amount of energy that a star emits is called its ______.&#10;A) astro energy&#10;B) luminosity&#10;C) apparent magnitude&#10;D) apparent brightness

Accepted Answer

Luminosity refers to the total amount of energy that a star emits in one second; it is a measure of the intrinsic brightness of a celestial object, independent of its distance from the observer.

Question 2

The brightness of a star at 10 parsecs is called the star's ______.&#10;A) apparent brightness&#10;B) apparent luminosity&#10;C) absolute magnitude&#10;D) parsec magnitude

Accepted Answer

Absolute magnitude is a measure of the intrinsic brightness of a celestial object, such as a star, as it would appear if it were located at a standard distance of 10 parsecs from the observer.

Question 3

The person who first started the magnitude scale for stars was _____.&#10;A) Kepler&#10;B) Aristotle&#10;C) Hipparchus&#10;D) Copernicus

Accepted Answer

Hipparchus is credited with creating the first known star catalog in the 2nd century BCE, which included a magnitude scale for ranking the brightness of stars. This system is the basis for the modern magnitude scale used in astronomy.

Question 4

Star A has an apparent magnitude of 5. Star B has an apparent magnitude of 3.&#10;A) Star A is 2.512 times brighter than star B&#10;B) Star A is 6.310 times brighter than star B&#10;C) Star B is 2.512 times brighter than star A&#10;D) Star B is 6.310 times brighter than star A

Accepted Answer

The formula for apparent magnitude is m = -2.5 log(L/L0), where m is the apparent magnitude, L is the luminosity of the star, and L0 is the luminosity of the reference star.Star A has an apparent magnitude of 5, so m1 = -2.5 log(L1/L0).Star B has an apparent magnitude of 3, so m2 = -2.5 log(L2/L0).Dividing the first equation by the second equation, we get:m1/m2 = (L1/L0)/(L2/L0)m1/m2 = L1/L2Substituting the given values, we get:5/3 = L1/L2L1 = 5/3 L2Therefore, Star A is 5/3 = 1.667 times brighter than Star B.

Question 5

The device called a ___________ measures the light output of a star.

Accepted Answer

The answer of The device called a ___________ measures the...

Question 6

In apparent magnitude the difference of one magnitude represents about ___ times difference in brightness.

Accepted Answer

The answer of In apparent magnitude the difference of one...

Question 7

Absolute magnitude is the brightness of a star in the night sky.

Accepted Answer

Absolute magnitude is a measure of the intrinsic brightness of a celestial object, as it would appear if it were placed at a standard distance of 10 parsecs from Earth, not its brightness as seen in the night sky.

Question 8

Luminosity is expressed as watts or wattage.

Accepted Answer

Luminosity, in the context of astronomy, refers to the total amount of energy emitted by an object (such as a star) per unit time, and it is indeed expressed in watts, which is the SI unit of power.

Deck 55: The Luminosities of Stars