IOAA Jr. 2022, Теория, първа дълга задача — Задача 1. Zodiac IOAA – J - 2022

Problem 1. Zodiac IOAA – J - 2022

Условие

In their apparent motions, the Moon and the other large planets in our solar system do not stray far from the plane of the ecliptic. Their apparent trajectories described on the celestial sphere remain contained in a region that extends symmetrically on both sides of the ecliptic, having a total width of about 18º. In the drawing in figure 1, in the plane of the ecliptic, the heliocentric orbit of the Earth is shown, and in the drawing in figure 2, the equivalent apparent geocentric orbit of the Sun, in relation to the Earth, is shown.

Heliocentric drawing in the plane of the ecliptic: a grey disc divided by white radial lines into 12 sectors, with the zodiac constellations drawn around the rim and labelled 1-Aries, 2-Taurus, 3-Gemini, 4-Cancer, 5 -Leo, 6-Virgo, 7-Libra, 8-Scorpionul, 9-Sagittarius, 10-Capricorn, 11-Aquaris, 12-Pisces. The Sun S is at the centre; the Earth E moves on an elliptical orbit (arrows show the direction of motion). A dashed line through the Sun joins the orbit points marked 4 VII and 3 I; the label t_R,2 is near Scorpio.
Fig. 1
Geocentric drawing: the same grey zodiac disc with 12 sectors and constellations labelled 1-Aries, 2-Taurus, 3-Gemini, Cancer, 5-Leo, Virgo, 7-Libra, 8-Scorpion, 9-Sagittarius, 10-Capricorn, 11-Aquaris, 12-Pisces. The Earth E (black dot) is at the centre; the Sun S moves on an apparent elliptical orbit around it, with an arrow showing the direction of motion. A dashed line through the Earth joins the orbit points marked 3 I and 4 VII.
Fig. 2
Enlarged copy of figure 2: the geocentric zodiac disc with the Earth at the centre, the Sun on its apparent elliptical orbit, the dashed line joining 3 I and 4 VII, and the constellations labelled 1-Aries, 2-Taurus, 3-Gemini, Cancer, 5-Leo, Virgo, 7-Libra, 8-Scorpion, 9-Sagittarius, 10-Capricorn, 11-Aquaris, 12-Pisces.
Figure 2, reproduced in enlarged format! This image will be worked on and will be handed in with the competition sheets!

The time intervals of the evolution of the true Sun in each of the 12 constellations of the Zodiac are as follows: 1) Aries, 21 III - 20 IV; 2) Taurus, 21 IV - 20 V; 3) Gemini, 21 V - 20 VI; 4) Cancer, 21 VI - 22 VII; 5) Leo, 23 VII - 22 VIII; 6) Virgo, 23 VIII - 22 IX; 7) Libra, 23 IX - 22 X; 8) Scorpio, 23 X - 21 XI; 9) Sagittarius, 22 XI - 21 XII; 10) Capricorn, 22 XII - 21 I; 11) Aquarius, 22 I - 19 II; 12) Pisces, 20 II - 21 III.

The International Olympics of Astronomy and Astrophysics for Juniors, Edition I, was to take place in SUCEAVA, in ROMANIA, on March 28 - April 3, 2020. The event, proposed by ROMANIA, was established at the International Olympics of Astronomy and Astrophysics, 13th Edition, held in Hungary, on August 2-10, 2019.

But, given the known conditions, OIAA for Juniors, Edition I, is taking place in Romania, only now, in November 2022!

a) Identify:

1. the sign of the OIAA development, 13th Edition, Hungary, August 2 - 10, 2019;

2. the sign when the OIAA - J was to take place - Edition I, March 28 - April 3, 2020, Romania (Edition I, proposal);

3. the sign of the OIAA - J - Edition I, November, 2022.

b) Each of the 3 specified Olympic events can be considered to have taken place on the day when the Sun, viewed from Earth, was in the middle of the angular range corresponding to each of the 3 signs.

1. Determine the time interval between any two of these three events:

ΔtH−R,1; ΔtR,1−R,2; ΔtH−R,2.\Delta t_{\mathrm{H-R,1}};\ \Delta t_{\mathrm{R,1-R,2}};\ \Delta t_{\mathrm{H-R,2}}.

2. Estimate, by direct measurements on the drawing, by means of a protractor, the value of the angle between the position vector of the Earth, in relation to the Sun, corresponding to each of the three specified moments, ie the directions of the vectors r⃗H\vec{r}_{\mathrm{H}}, r⃗R,1\vec{r}_{\mathrm{R,1}} and respectively r⃗R,2\vec{r}_{\mathrm{R,2}}, and the direction of the apse line, Aph – Ph, ie the angles αH\alpha_{\mathrm{H}}, αR,1\alpha_{\mathrm{R,1}} and respectively αR,2\alpha_{\mathrm{R,2}}.

c) Determine the area of the surface described by the position vector of the center of the Earth, r⃗\vec{r}, in relation to the center of the Sun:

1. from position r⃗Hungry\vec{r}_{\mathrm{Hungry}} to position r⃗Romania,1\vec{r}_{\mathrm{Romania,1}};

2. from position r⃗Romania,1\vec{r}_{\mathrm{Romania,1}} to position r⃗Romania,2\vec{r}_{\mathrm{Romania,2}};

3. from position r⃗Hungry\vec{r}_{\mathrm{Hungry}} to position r⃗Romania,2\vec{r}_{\mathrm{Romania,2}}.

d) Determine:

1. the distance between the Earth and the Sun, on the day when in Suceava, in 2020, the IOAA for Juniors, Edition I should have taken place, rR,1r_{\mathrm{R,1}}, if, for the ellipse representing the Earth's orbit around the Sun, the following are known: large semiaxis, a=149 597 500 kma = 149\,597\,500\ \mathrm{km} and small semiaxis, b=149 580 670 kmb = 149\,580\,670\ \mathrm{km};

2. the acceleration of the center of the Earth, on the day when in Suceava, in 2020, the IOAA for Juniors should have taken place, aE,1a_{\mathrm{E,1}}, and compared with the gravitational acceleration in the gravitational field of the Sun, corresponding to the distance rR,1r_{\mathrm{R,1}} from the center of the Sun, gS,1g_{\mathrm{S,1}};

3. the components of the speed of the center of the Earth, v⃗R\vec{\mathrm{v}}_{\mathrm{R}}, parallel to the major axis of the ellipse and respectively perpendicular to the major axis of the ellipse, in the days of the International Olympics in Romania, v//\mathrm{v}_{//} and respectively v⊥\mathrm{v}_{\perp}.

It is known that the kinetic moment of the Earth in relation to the center of the Sun and the total mechanical energy of the Earth-Sun system are given by the expressions:

L=MEb⋅KMSa; E=−KMEMS2a.L = M_{\mathrm{E}}b\cdot\sqrt{\frac{KM_{\mathrm{S}}}{a}};\ E = -K\frac{M_{\mathrm{E}}M_{\mathrm{S}}}{2a}.

Given: gravitational attraction constant, K=6.67⋅10−11 Nm2kg−2K = 6.67\cdot 10^{-11}\ \mathrm{Nm^{2}kg^{-2}}; mass of the Sun, MS=1.989⋅1030 kgM_{\mathrm{S}} = 1.989\cdot 10^{30}\ \mathrm{kg}.

Enlarged copy of figure 1: the heliocentric zodiac disc with the Sun at the centre, the Earth E on its elliptical orbit, the dashed line joining 4 VII and 3 I, the label t_R,2 near Scorpio, and the constellations labelled 1-Aries to 12-Pisces (8-Scorpion, 11-Aquaris).
Figure 1, reproduced in enlarged format! This image will be worked on and will be handed in with the competition sheets!

Отговори

Решение


Оригинал в Архива: First_long_problem.pdf