Никола 2019, 28 септември · лист b — Задача 1. A new variable star
28 септември 2019г.
Внимание: Бележка към темата
The figures Fig. 1a, 1b, 1c referred to in the second problem are not included in the archive file.
Условие
During late winter – early spring, 2014, a recently discovered variable star GSC 4560-02157, in the constellation of Ursa Minor, was observed at the Tien Shan Observatory of the Kazakhstan Astrophysical Institute, located in the mountains to the south of Almaty city, approximately in 60 km to the north of Cholpon-Ata (Kyrgyzstan). The star features complex physical variability along with regular eclipses. During the night of February 28 – March 1, the star was observed non-stop for almost 9 hours. The table (right) presents the most important data points derived from these observations. The time in the table is the mean solar time for the Almaty time zone.
| T | m |
|---|---|
| 22 h 00 m (February 28) | 14.92 |
| 22 h 12 m | 15.08 |
| 22 h 24 m | 15.41 |
| 22 h 36 m | 15.44 |
| 22 h 48 m | 15.37 |
| 23 h 00 m | 15.12 |
| 23 h 12 m | 14.92 |
| 23 h 30 m | 14.89 |
| 00 h 00 m (March 1) | 14.80 |
| 00 h 18 m | 14.78 |
| 00 h 42 m | 14.80 |
| 01 h 00 m | 14.82 |
| 01 h 24 m | 14.85 |
| 01 h 48 m | 14.96 |
| 02 h 12 m | 14.72 |
| 02 h 30 m | 14.72 |
| 03 h 12 m | 14.63 |
| 03 h 36 m | 14.65 |
| 04 h 15 m | 14.77 |
| 04 h 25 m | 14.84 |
| 04 h 36 m | 15.10 |
| 05 h 00 m | 15.43 |
| 05 h 12 m | 15.32 |
| 05 h 24 m | 15.05 |
| 05 h 36 m | 14.90 |
| 05 h 48 m | 14.75 |
| 06 h 12 m | 14.73 |
| 06 h 48 m | 14.70 |
At times of the primary minimum, the star’s properties correspond to the K0 spectral type.
Plot the light curve. At the time axis, mark times of minimal brightness in the primary minima and in the secondary minimum. Knowing that the Julian date 2456949.000 begins at today’s (October 18) Greenwich noon, label the times of minimal brightness with their Julian dates, with three digits after the decimal point.
One of simplified models describing the event assumes that the process involves two stars only. From your analysis of the light curve in the frame of such a model, determine the spectral types (for example, that of the Sun is G2) of the larger (1) and smaller (2) components as well as the ratio of the radii of the larger () and smaller () components. Illustrate the solution with necessary figures.
Almaty and Cholpon-Ata are in the same time zone.
Решение
Внимание: Непълно решение
В архива няма официално решение на тази задача.
Оригинал в Архива: 28092019b.pdf