Astrophysics question about a binary star system (AQA exam)

In summary, the mark scheme for question 2 explains that the change in wavelength is not calculated by subtracting 656.05 from 656.52, but rather by measuring the amplitude of the wave relative to the unshifted wavelength of 656.28 nm. The maximum shift is ± 0.24 nm.
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bonbon22
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Homework Statement
https://pmt.physicsandmathstutor.com/download/Physics/A-level/Past-Papers/AQA-Old/Unit-5/June%202015%20QP%20-%20Unit%205-2A%20AQA%20Physics%20A-level.pdf
question 2
image below
Relevant Equations
change in wavelength
https://pmt.physicsandmathstutor.co...e 2015 MS - Unit 5-2A AQA Physics A-level.pdfmark scheme
question 2

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very simple question why is the change in wavlength not 656.05 - 656.52? instead.
The difference being in the mark scheme they have taken the greatest change in wavelength to be the amplitude of the wave not the peak to peak value. How does that make sense exactly.
 
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Because change in wavelength is measured relative to the unshifted wavelength of 656.28 nm. That is what we see when the velocity of the star relative to Earth is zero. The maximum shift is ± 0.24 nm.
 
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1. What is a binary star system?

A binary star system is a system of two stars that orbit around a common center of mass. They are bound together by their mutual gravitational attraction and can either have a circular or elliptical orbit.

2. How are binary star systems formed?

Binary star systems are formed from the same cloud of gas and dust that collapses to form a single star. As the cloud collapses, it breaks into smaller fragments which can then form into two separate stars.

3. Can binary star systems have more than two stars?

Yes, binary star systems can have more than two stars. These systems are called multiple star systems and can have three or more stars orbiting around each other.

4. What is the difference between a visual and spectroscopic binary star system?

A visual binary star system is one where the two stars can be seen separately through a telescope. A spectroscopic binary star system is one where the two stars cannot be resolved visually, but their presence is detected through changes in the spectrum of light emitted from the system.

5. How do scientists determine the properties of stars in a binary star system?

Scientists use various techniques, such as astrometry and spectroscopy, to study the orbits and characteristics of stars in a binary star system. They can also measure the amount of light and other emissions from the stars to determine their temperature, mass, and other properties.

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