Table 2 shows some properties of four stars in the constellation Delphinus.
| Name | Apparent magnitude | Absolute magnitude | Spectral class |
|---|---|---|---|
| Alpha Delphini | 3.77 | -0.40 | A |
| Beta Delphini | 3.63 | 1.23 | F |
| Gamma Delphini | 5.15 | -1.10 | K |
| HD 196567 | 5.82 | -2.30 | K |
Discuss, with reference to the Hipparcos scale, why many star maps show only two stars in the constellation Delphinus.
State and explain which star in Table 2 has the most prominent Hydrogen Balmer absorption lines.
Deduce which star, Gamma Delphini or HD 196567, has the larger diameter.
Astronomers recently used the radial velocity method to discover an exoplanet orbiting HD 196567. Describe the main features of the radial velocity method in the detection of planets.
Calculate the distance from the Earth to Beta Delphini. Give an appropriate unit for your answer.
