7th International Earth Science Olympiad

Student Code:

Theoretical Test
Astronomy
Time: 45 Minutes

Maximum Marks: 28.5

Instructions:
1. Please write your student code on the cover page as well as on the top right ofevery page of answer sheet / calculations sheets.
2. Please write your answers legibly. Illegible answers will be counted asincorrect.
3. Please write your final answers in appropriate boxes in the main answer sheet.
For numerical questions, show the calculations on blank calculation sheets
provided.
4. For numerical questions, you may attempt part of the answer even if you don't
know the final result. There will be stepwise marking.
5. You can get as many calculations sheets as you want. Just raise your hand toask for extra sheets. The volunteers will bring extra sheets to your table.
6. Write question number clearly at the top of the calculations sheet.
7. Read the entire question group carefully before starting to answer. Eachquestion has a point value assigned and indicated on the right hand side of thequestion.
8. Any inappropriate examination behaviour will result in your withdrawal fromthe IESO.

Mysore, India, September 11 – 19, 2013

(Theory Test - Astronomy)

7th International Earth Science Olympiad

Student Code:A1. We list a few facts below about temperatures at the surface of Venus, Earth and Mars.
(a) The yearly mean temperatures of planets do not match with their expected black body temperature.
(b) Absolute variation in the temperature during the course of one day differs significantly from one
planet to another.
(c) Absolute variation in the temperature during the course of one year at the equator of the planet
differs significantly from one planet to another.
(d) On some planets, there is a large latitudinal percentage variation in temperatures.
(e) Mean temperature (averaged over a day) on Earth is different on different days.
In the table given in your answer sheet, we list a number of physical properties related to a planet and its various
motions, which may or may not be relevant in explaining the facts above. In the table, tick in appropriate rows
those properties which are relevant for each of the facts above. Number of relevant parameters for each row can benone, one or more than one.
Total 10 points for correct tick-marks.
Warning: Every wrong tick mark has penalty of -0.2 points.
A2. The maximum altitude of the Sun as seen from Mysore on summer solstice day and winter solstice
day are 78o 51' and 54o 17' respectively. Using this information, obtain the inclination of the Earth's
axis (ε) and find the latitude of Mysore (φ).
(6 points)

A3. The mass ratio of Pluto and Charon is 8:1. The period of revolution of Charon around Pluto
is about 6.387 days. You are given thatMPluto = 1.31 x 1022 kg,
RPluto = 1195 km,
G = 6.672 x 10-11 N m2 kg-2
the Minimum and maximum distance of Pluto from Earth are 4284.7 x 106 km and7528 x 106 km respectively.
(a) Find the length of the semi-major axis of Charon's orbit of revolution about Pluto.
(3 points)(b) Find the ratio a:RPluto, where 'a' is the distance of the Centre of Mass of the PlutoCharon system from the center of Pluto .
(2 points)(c) Theoretically, what is the minimum diameter of the optical telescope which canresolve the system from Earth? Ignore effects of Earth's atmosphere.(2 points)
A4. The diagram on the next page shows the Hertzprung-Russell diagram (H-R diagram)with six positions (A – F) indicated. The y-axis is given in terms of Solar Luminosity(L ) and x-axis gives effective surface temperature (T) of stars in Kelvin.
(a) Which letters indicate the position of stars that have the largest and the smallest
diameters respectively?
(2 points)(b) Which letters indicate the stars with the same spectral class but with different
luminosities?
(1 points)(c) Which letters indicate the stars that are primarily burning Hydrogen? (1.5 points)(d) Which letter would indicate position of a white dwarf in this diagram? (1 point)

Mysore, India, September 11 – 19, 2013

(Theory Test - Astronomy)

7th International Earth Science Olympiad

Mysore, India, September 11 – 19, 2013

Student Code:(Theory Test - Astronomy)

7th International Earth Science Olympiad

Student Code:

Theoretical Test
Astronomy Answer Sheet
A1.

Please see next page

A2.

Inclination of the Earth's axis is

Latitude of Mysore is

A3.
Pluto and Charon:(a) Semi-major axis =(b) a:b =(c) Diameter =A4.
H-R diagram(a) Star of Largest DiameterStar of Smallest Diameter(b) Give letters of stars(c) Give letters of stars(d) White Dwarf letter

Mysore, India, September 11 – 19, 2013

(Theory Test - Astronomy)

7th International Earth Science Olympiad

Student Code:Sheet for numerical calculations (write question number clearly)

Mysore, India, September 11 – 19, 2013

(Theory Test - Astronomy)