The period of a pulsating star with respect to the star

In summary, the period of a pulsating star is 3 seconds in its rest mass frame. When observed by an observer traveling at a velocity of 2.4 x 108 m/s with respect to the star, the period will be affected by the Doppler effect. It is not specified if the observer is moving towards or away from the star, but it is assumed to be away based on standard convention.
  • #1
ktdraho
1
0

Homework Statement



A pulsating star has a period of 3 sec as seen from the rest mass frame of the star. What is the period of the star as measured by an observer traveling 2.4 x 108 m/s with respect to the star?


Homework Equations





The Attempt at a Solution

 
Physics news on Phys.org
  • #2
How do you think you should start?
 
  • #3
I'd think you'd need to use Doppler. The frequency changes due to the motion, although it doesn't say which way, and you have the frequency when there's no relative motion.
 
  • #4
That sounds good, it should work. And that's a good point, they don't seem to say if they are moving towards or away. I'd guess away, as the standard convention is: negative velocities mean approaching each other.
 
  • #5


I would approach this problem by utilizing the concept of time dilation in special relativity. Time dilation states that the passage of time is relative to the observer's frame of reference and is affected by their relative velocity. In this case, the observer is traveling at a velocity of 2.4 x 108 m/s with respect to the star, which means that their frame of reference is moving at a high velocity compared to the rest mass frame of the star.

To find the period of the star as measured by the observer, we can use the equation T' = T/√(1-(v/c)^2), where T' is the observed period, T is the rest frame period, v is the relative velocity, and c is the speed of light. Plugging in the given values, we get T' = 3/√(1-(2.4x108/3x108)^2) = 3/√(1-0.64) = 3/√0.36 = 3/0.6 = 5 seconds.

Therefore, the period of the pulsating star as measured by the observer traveling at 2.4 x 108 m/s is 5 seconds. This means that the observer would perceive the star's pulsations to be slower than they actually are in the rest mass frame of the star. This is due to the time dilation effect caused by their relative velocity.
 

What is the period of a pulsating star?

The period of a pulsating star refers to the time it takes for the star to complete one full cycle of its pulsations. This can range from minutes to years, depending on the type of star.

How is the period of a pulsating star measured?

The period of a pulsating star is measured by observing its brightness over time. As the star pulsates, it becomes brighter and dimmer in a regular pattern, allowing scientists to calculate the period of its pulsations.

What causes a star to pulsate?

A star pulsates due to internal processes, such as changes in temperature and density, that create pressure waves in the star's outer layers. These pressure waves cause the star's surface to expand and contract, resulting in the pulsations.

Can the period of a pulsating star change?

Yes, the period of a pulsating star can change over time. This can be due to various factors, such as changes in the star's internal structure or the influence of nearby stars or planets.

What can studying the period of a pulsating star tell us?

Studying the period of a pulsating star can provide valuable information about its internal structure, age, and evolution. It can also help us understand the characteristics and behavior of other stars in the same class.

Similar threads

Replies
0
Views
195
  • Introductory Physics Homework Help
Replies
6
Views
577
  • Introductory Physics Homework Help
Replies
15
Views
1K
  • Introductory Physics Homework Help
Replies
13
Views
2K
  • Introductory Physics Homework Help
Replies
2
Views
872
  • Introductory Physics Homework Help
Replies
3
Views
1K
  • Introductory Physics Homework Help
Replies
8
Views
2K
  • Introductory Physics Homework Help
Replies
5
Views
1K
  • Introductory Physics Homework Help
Replies
1
Views
866
  • Introductory Physics Homework Help
Replies
10
Views
2K
Back
Top