An astronomer uses one ground-based optical telescope to observe two stars that are close together in the sky.
The table gives the minimum and maximum apparent position of one star, measured from a fixed reference point, during observations on two clear nights. Positions are measured in arcseconds, a very small unit of angle.
| night | minimum apparent position in arcseconds | maximum apparent position in arcseconds |
|---|---|---|
| A | -0.09 | +0.13 |
| B | -0.31 | +0.27 |
The two stars are separated by 0.40 arcseconds. The detector records the stars separately only when the total range of apparent position is less than their separation.
Explain which night had more movement of air in the atmosphere and which night would allow the two stars to be recorded separately.
75 exam-style questions on Edexcel GCSE Physics 7.3 Stars, covering 7.3.1 Evolution of stars similar to the Sun, 7.3.2 Evolution of massive stars, and 7.3.3 Observing the Universe. Each one has a worked solution and a mark scheme showing where the marks go.