Question 1

Cepheid's have pulsation periods in the range of _____.&#10;A) 1-700 hours&#10;B) 1-70 days&#10;C) 1-70 minutes&#10;D) 1-70 hours

Accepted Answer

Cepheid variables are a type of star that pulsates radially, varying in both diameter and temperature, which leads to changes in brightness with a well-defined stable period. These periods range from 1 to 70 days, making them important standard candles for measuring cosmic distances.

Question 2

Mira variable stars change their brightness by&#10;A) carbon fusion.&#10;B) hydrogen fusion.&#10;C) molecules in cool atmosphere.&#10;D) PP reaction.

Accepted Answer

Mira variable stars change their brightness primarily due to changes in their cool atmospheres. These changes are not directly related to nuclear fusion processes but rather to the physical and chemical processes in their extended, cool atmospheres, which cause the stars to pulsate and vary in brightness.

Question 3

We use this to help measure the distance to variable stars:&#10;A) period-mass&#10;B) period-size&#10;C) period luminosity&#10;D) mass-distance

Accepted Answer

The period-luminosity relationship is used to measure the distance to variable stars, particularly Cepheid variables. This relationship indicates that the intrinsic brightness (luminosity) of these stars is directly related to their pulsation period, allowing astronomers to determine their distance from Earth.

Question 4

The layer in a variable that star that is responsible for alternately absorbing and releasing the energy flowing from the center of the star is made up of&#10;A) fusing hydrogen.&#10;B) molecules of metal oxides.&#10;C) fusing helium.&#10;D) partially ionized helium.

Accepted Answer

The layer responsible for alternately absorbing and releasing energy in a variable star is made up of partially ionized helium. This process contributes to the pulsation and variability of the star's brightness.

Question 5

A narrow area above the main sequence where variable stars exist is called the _______.

Accepted Answer

The answer of A narrow area above the main sequence...

Question 6

A large explosion of a star is known as a _______.

Accepted Answer

The answer of A large explosion of a star is...

Question 7

Mira variables have a period of about a day.

Accepted Answer

Mira variables are a type of pulsating variable star characterized by very red colors, late spectral types of K, M, S, and C, and pulsation periods ranging from about 80 to more than 1,000 days, much longer than a day.

Question 8

Using the period of bright stars and the standard candle formula you can measure distances to galaxies at the edge of the universe.

Accepted Answer

The period-luminosity relationship of bright stars, such as Cepheid variables, is indeed used to measure distances, but it is effective only for relatively nearby galaxies (up to about 100 million light-years away). For galaxies at the edge of the universe, astronomers use other methods, such as Type Ia supernovae or redshift measurements, which are applicable over much larger distances.

Deck 64: Variable Stars