IAO 2018, Практически тур — Задача 6α. Pulsation period of a variable star

IAO 2018 — Practical round (α and β)

Practical round. Problems to solve

XXIII International Astronomy Olympiad. Colombo, Sri Lanka, 6–14 X 2018. This source combines groups α and β. The distinct task 6 of each group is identified as 6α and 6β; tasks 7 and 8 are shared and are reproduced once.

Бележки от източника

The repeated 0.25, 0.32 and 0.37 Julian-day entries in the α table 6 are retained exactly. The α data sheet bears the header Theo although the body says Practical round. Question 8.5 refers to provided graph paper, which is absent from this source pack. Matching official practical solutions were not found in the complete same-year catalogue.

Shared reference inventory

The two separately archived data photographs are labelled Theo: data_1 contains Solar-System properties, the equation of time and Colombo coordinates; data_2 contains physical constants and formulae. They were read to check reference coverage and do not contain missing practical graph paper, additional practical tasks or official solutions.

Условие

SZ Lyn is a δ Scuti (δ Sct) type short period pulsating star. The star is observed in B band at Mount Abu Observatory, India. The light curve data are given in the table 6. The differential magnitudes were taken by observing a comparison star in the same field. The time is in Julian Days (JD). This data set is only for one observation night and therefore integer part of the JD does not change. You are asked to produce the light curve for this observation.

6.1 Plot the data points, differential magnitude against the Julian Day (JD).

6.2 Draw a smooth light curve through the data points.

6.3 The period of pulsation is assumed to be the time between consecutive maxims in the light curve. Estimate the pulsation period ($P$) of SZ Lyn.

6.4 Calculate the absolute magnitude of SZ Lyn, if the period–luminosity relationship for δ Scuti type stars is given by empirical formula

6.5 If the apparent magnitude ($m_B$) of SZ Lyn is $9.7^{\mathrm m}$, estimate the distance to SZ Lyn.

Table 6

JD 2456664.0+	Differential magnitude
0.23	-1.60
0.24	-1.73
0.25	-1.98
0.25	-2.24
0.26	-2.33
0.27	-2.22
0.28	-2.07
0.29	-1.95
0.30	-1.84
0.31	-1.72
0.32	-1.68
0.32	-1.66
0.33	-1.64
0.34	-1.63
0.35	-1.67
0.36	-1.72
0.37	-1.89
0.37	-2.09
0.38	-2.29
0.39	-2.27
0.40	-2.05
0.41	-1.95
0.42	-1.84
0.43	-1.78
0.44	-1.71
0.45	-1.64

Решение

Теми и трудност

Трудност: неоценена.

Звезди · Светлина и астрономически измервания · Променливи звезди · Звездни величини

Предпоставки: Разширена олимпиадна подготовка

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Оригинал в Архива: pract.pdf · допълнителни данни: data_1.jpg · допълнителни данни: data_2.jpg