International Olympiad on Astronomy and Astrophysics

The International Olympiad on Astronomy and Astrophysics (IOAA) is a global competition for secondary school students. It features multiple components such as theory and data analysis rounds. This archive contains publicly shared problem and solution PDFs from past editions listed by IOAA.

2025 Mumbai, India
Theory
Theory Problems Theory Solutions Theory Instructions Theory Answer Sheet Theory Results
Problem T1 (10 pts)
Daksha Mission Theory
Problem T2 (10 pts)
Makar-Sankranti Theory
Problem T3 (15 pts)
Gravitational Waves Theory
Problem T4
Balmer Decrement Theory
Problem T5 (20 pts)
Quasars Theory
Problem T6 (20 pts)
Galactic Rotation Theory
Problem T7 (20 pts)
Neutron Star Binary Theory
Problem T8 (20 pts)
Shadow of a black hole Theory
Problem T9
Atmospheric Seeing Theory
Problem T10 (35 pts)
Big Bang Nucleosynthesis Theory
Problem T11 (50 pts)
Stars through graphs Theory
Problem T12
Hawking Radiation from Black Holes Theory
Data Analysis
Data Analysis Problems Data Analysis Solutions Data Analysis Instructions Data Analysis Answer Sheet Data Analysis Results
Problem D1 (90 pts)
30 Years of Exoplanets Data Analysis
Problem D2 (60 pts)
Predicting arrival times of coronal mass ejections on Earth Data Analysis
2024 Rio de Janeiro, Brazil
Theory
Theory Problems Theory Solutions Theory Grading Scheme Theory Results
Problem T1 (10 pts)
Sundial Theory
Problem T2 (10 pts)
Galaxy Cluster Theory
Problem T3 (10 pts)
Asteroid Theory
Problem T4 (10 pts)
White Dwarf Theory
Problem T5 (10 pts)
CMB Theory
Problem T6 (20 pts)
Cluster Photography Theory
Problem T7 (20 pts)
Castaway Theory
Problem T8 (25 pts)
Binary Hardening Theory
Problem T9 (35 pts)
Physics of Accretion Theory
Problem T10 (75 pts)
Greatest Eclipse Theory
Problem T11 (75 pts)
Ground Tracks Theory
Data Analysis
Data Analysis Problems Data Analysis Solutions Data Analysis Grading Scheme Data Analysis Results
Problem D1 (75 pts)
Photometric comparison of surveys Data Analysis
Problem D2 (75 pts)
Shapley Hypothesis Data Analysis
2023 Katowice, Poland
Theory
Theory Problems Theory Solutions Theory Results
Problem T1 (5 pts)
Neptune Theory Short
Problem T2 (5 pts)
Magnetic field Theory Short
Problem T3 (5 pts)
Microlensing Theory Short
Problem T4 (10 pts)
Europa Theory Short
Problem T5 (12 pts)
Dark Energy Theory Short
Problem T6 (13 pts)
Bolometer Theory
Problem T7 (20 pts)
Libration Theory
Problem T8 (20 pts)
Neutrinos Theory
Problem T9 (20 pts)
Second eclipse Theory
Problem T10 (25 pts)
Aldebaran Theory
Problem T11 (30 pts)
X-ray emission from galaxy clusters Theory Long
Problem T12 (40 pts)
DART Theory Long
Problem T13 (45 pts)
LISA Theory Long
Data Analysis
Data Analysis Problems Data Analysis Solutions Data Analysis Results
Problem D1 (50 pts)
Distance to the Large Magellanic Cloud Data Analysis
Problem D2 (75 pts)
Isolated black hole Data Analysis
2022 Kutaisi, Georgia
Theory
Theory Problems Theory Solutions Theory Results
Problem T1 (10 pts)
Planck's units Theory
Problem T2 (10 pts)
Circumbinary planet Theory
Problem T3 (10 pts)
Expanding ring nebula Theory
Problem T4 (10 pts)
Journey Between Galaxies Theory
Problem T5 (10 pts)
Flaring protoplanetary disk Theory
Problem T6 (20 pts)
Photometry of Binary stars Theory
Problem T7 (20 pts)
Georgia to Georgia Theory
Problem T8 (20 pts)
Ring of a planet Theory
Problem T9 (20 pts)
Solar Retrograde Motion on Mercury Theory
Problem T10 (20 pts)
Accretion Theory
Problem T11 (50 pts)
Dyson Sphere Theory
Problem T12 (50 pts)
Co-orbital satellites Theory
Problem T13 (50 pts)
Relativistic Beaming Theory
Data Analysis
Data Analysis Problems Data Analysis Results
Problem D1 (45 pts)
Gravitational wave astronomy Data Analysis
Solution
Problem D2 (105 pts)
Galactic Surveys Data Analysis
Solution
2021 Bogota, Colombia
Theory
Theory Instructions Theory Results
Problem T1 (5 pts)
LIGO Theory
Problem Solution
Problem T2 (10 pts)
Temperature of the Earth Theory
Problem Solution
Problem T3 (10 pts)
Mars Theory
Problem Solution
Problem T4 (10 pts)
ALMA - Calculating photons Theory
Problem Solution
Problem T5 (10 pts)
Under pressure Theory
Problem Solution
Problem T6 (12 pts)
Macondo and Melquiades Theory
Problem Solution
Problem T7 (13 pts)
Menkalinan (β Aurigae) Theory
Problem Solution
Problem T8 (15 pts)
IOAA Logo Theory
Problem Solution
Problem T9 (15 pts)
Pluto Satellites Theory
Problem Solution
Problem T10 (15 pts)
Terrestrial Transit Theory
Problem Solution
Problem T11 (15 pts)
Minimum velocity of a projectile Theory
Problem Solution
Problem T12 (15 pts)
Hodograph Theory
Problem Solution
Problem T13 (15 pts)
Lucy: The First Mission to the Trojan Asteroids Theory
Problem Solution
Problem T14 (35 pts)
Formation of the Venus-2 Theory
Problem Solution
Problem T15 (55 pts)
Cosmic String Theory
Problem Solution
Data Analysis
Data Analysis Results
Problem D1 (75 pts)
Scaling Relations Data Analysis 1
Problem Solution
Problem D2 (75 pts)
Stars and Exoplanets Data Analysis 2
Problem Solution
2020 Estonia
Theory
Theory Solutions Theory Results
Problem T1 (10 pts)
Astrophotography Theory
Problem T2 (10 pts)
Flat Earth Theory
Problem T3 (10 pts)
Mirror Theory
Problem T4 (20 pts)
Light Curves Theory
Problem T5 (20 pts)
HII region Theory
Problem T6 (20 pts)
Occultation of an X-ray Source Theory
Problem T7 (30 pts)
Radiant of a Meteor Shower Theory
Problem T8 (30 pts)
Jupiter's Great Red Spot Theory
Data Analysis
Data Analysis Solutions Data Analysis Results
Problem D1 (15 pts)
AGN Data Analysis
Problem D2 (50 pts)
Minor Planet Data Analysis
Problem D3 (55 pts)
Hypervelocity Stars Data Analysis
2019 Keszthely, Hungary
Theory
Theory Problems Theory Solutions Theory Answer Sheet Theory Results
Problem T1 (10 pts)
Famous astronomical events Theory
Problem T2 (10 pts)
Deflection of radio photons in the gravitational field of solar system bodies Theory
Problem T3 (10 pts)
The supermassive black hole in the centre of Milky Way Galaxy and M87 Theory
Problem T4 (10 pts)
Improving a common reflecting telescope Theory
Problem T5 (10 pts)
Cosmic Microwave Background Oven Theory
Problem T6 (20 pts)
The height of the chimney of Tiszaujvaros power plant Theory
Problem T7 (20 pts)
Effect of sunspots on solar irradiance Theory
Problem T8 (20 pts)
Amplitude variation of RR Lyrae stars Theory
Problem T9 (20 pts)
Distance of the Lagrangian point L2 of the Earth-Moon system Theory
Problem T10 (20 pts)
South to East to North Theory
Problem T11 (25 pts)
Identification of light curves of selected variable star types Theory
Problem T12 (25 pts)
Distance to a Near-Earth Asteroid Theory
Problem T13 (40 pts)
Distance to the Coma galaxy cluster Theory
Problem T14 (60 pts)
Photographing a nanosatellite Theory
Data Analysis
Data Analysis Problems Data Analysis Solutions Data Analysis Answer Sheet Data Analysis Results
Problem D1 (60 pts)
Photometry and spectroscopy of Nova Del 2013 Data Analysis
Problem D2 (90 pts)
Triply eclipsing hierarchical triple stellar system Data Analysis
2018 Beijing, China
Theory
Theory Problems Theory Solutions Theory Answer Sheet
Problem T1 (10 pts)
Super Luminal Galaxies Theory
Problem T2 (10 pts)
Distance Theory
Problem T3 (10 pts)
Atmospheric Refraction Theory
Problem T4 (10 pts)
Height of a Hill Theory
Problem T5 (10 pts)
Sidereal Time Theory
Problem T6 (25 pts)
Observe the Sun with FAST Theory
Problem T7 (25 pts)
Sunspot Theory
Problem T8 (25 pts)
A Possible Dark Matter Deficient Galaxy Theory
Problem T9 (25 pts)
Radio Galaxy Theory
Problem T10 (75 pts)
Vega and Altair Theory
Problem T11 (75 pts)
Thermal History of the Universe Theory
Data Analysis
Data Analysis Problems Data Analysis Solutions Data Analysis Answer Sheet
Problem D1
Dust and Young Stars in Star-forming Galaxies Data Analysis
Problem D2
Compact Object in a Binary System Data Analysis
2017 Phuket, Thailand
Theory
Theory Problems Theory Solutions Theory Results
Problem T1 (10 pts)
The Large Magellanic Cloud in Phuket Theory
Problem T2 (10 pts)
Earth's Transit Zone Theory
Problem T3 (10 pts)
The Milky Way's Distant Outer Arm Theory
Problem T4 (10 pts)
21-cm HI galaxy survey Theory
Problem T5 (10 pts)
A Synchronous Satellite Theory
Problem T6 (15 pts)
Supernova 1987A Theory
Problem T7 (20 pts)
Life on Other Planets Theory
Problem T8 (20 pts)
The Star of Bethlehem Theory
Problem T9 (20 pts)
Galactic Outflow Theory
Problem T10 (25 pts)
GOTO Theory
Problem T11 (50 pts)
Mass of the Local Group Theory
Problem T12 (40 pts)
Shipwreck Theory
Problem T13 (60 pts)
Exomoon Theory
Data Analysis
Data Analysis Problems Data Analysis Solutions Data Analysis Results
Problem D1 (75 pts)
Calibrating distance ladder to the LMC Data Analysis
Problem D2 (75 pts)
The search for dark matter Data Analysis
2016 Bhubaneswar, India
Theory
Theory Problems Theory Solutions Theory Results
Problem T1 (10 pts)
True or False Theory
Problem T2 (10 pts)
Gases on Titan Theory
Problem T3 (10 pts)
Early Universe Theory
Problem T4 (10 pts)
Shadows Theory
Problem T5 (10 pts)
GMRT beam transit Theory
Problem T6 (20 pts)
Cepheid Pulsations Theory
Problem T7 (20 pts)
Telescope optics Theory
Problem T8 (20 pts)
U-Band photometry Theory
Problem T9 (20 pts)
Mars Orbiter Mission Theory
Problem T10 (20 pts)
Gravitational Lensing Telescope Theory
Problem T11 (50 pts)
Gravitational Waves Theory
Problem T12 (50 pts)
AstroSat Theory
Data Analysis
Data Analysis Problems Data Analysis Solutions Data Analysis Results
Problem D1 (50 pts)
Binary Pulsar Data Analysis
Problem D2 (50 pts)
Distance to the Moon Data Analysis
Problem D3 (50 pts)
Type IA Supernovae Data Analysis
2015 Central Java, Indonesia
Theory
Theory Problems Theory Solutions Theory Results
Problem S1 (100 pts)
Theory
Problem S2 (100 pts)
Theory
Problem S3 (100 pts)
Theory
Problem S4 (100 pts)
Theory
Problem S5 (100 pts)
Theory
Problem S6 (100 pts)
Theory
Problem S7 (100 pts)
Theory
Problem S8 (100 pts)
Theory
Problem S9 (100 pts)
Theory
Problem S10 (100 pts)
Theory
Problem S11 (100 pts)
Theory
Problem S12 (100 pts)
Theory
Problem S13 (100 pts)
Theory
Problem S14 (100 pts)
Theory
Problem S15 (100 pts)
Theory
Problem L1 (100 pts)
Theory
Problem L2 (100 pts)
Theory
Problem L3 (100 pts)
Theory
Data Analysis
Data Analysis Problems Data Analysis Solutions Data Analysis Results
Problem D1 (100 pts)
Data Analysis
Problem D2 (100 pts)
Data Analysis
2014 Suceava, Gura Humorului, Romania
Theory
Theory Problems Theory Solutions Theory Results
Problem S1 (10 pts)
Lagrange Points Theory
Problem S2 (10 pts)
Sun gravitational catastrophe! Theory
Problem S3 (10 pts)
Cosmic radiation Theory
Problem S4 (10 pts)
Mass function of a visual binary stellar system Theory
Problem S5 (10 pts)
The Astronaut saved by... ice from a can! Theory
Problem S6 (10 pts)
The life-time of a star from the main sequence Theory
Problem S7 (10 pts)
The effective temperature on the surface of a star Theory
Problem S8 (10 pts)
Gradient temperatures Theory
Problem S9 (10 pts)
Pressure of light Theory
Problem S10 (10 pts)
The density of the star Theory
Problem S11 (10 pts)
Space-ship orbiting the Sun Theory
Problem S12 (10 pts)
The Vega star in the mirror Theory
Problem S13 (10 pts)
Stars with Romanian names Theory
Problem S14 (10 pts)
Apparent magnitude of the Moon Theory
Problem S15 (10 pts)
Absolute magnitude of a cepheid Theory
Problem L1 (50 pts)
Eagles on the Caraiman Cross! Theory
Problem L2 (50 pts)
Cosmic Pendulum Theory
Problem L3 (50 pts)
From Romania... to Antipod!... A ballistic messenger Theory
Data Analysis
Data Analysis Problems Data Analysis Solutions Data Analysis Results
Problem D1 (50 pts)
Black Hole in Milky Way Data Analysis
Problem D2 (25 pts)
Thermodynamic test Data Analysis
Problem D3 (25 pts)
Observer on an extrasolar planet Data Analysis
2013 Volos, Greece
Theory
Theory Solutions Theory Results
Problem S1 (10 pts)
Theory
Problem S2 (10 pts)
Theory
Problem S3 (10 pts)
Theory
Problem S4 (10 pts)
Theory
Problem S5 (10 pts)
Theory
Problem S6 (10 pts)
Theory
Problem S7 (10 pts)
Theory
Problem S8 (10 pts)
Theory
Problem S9 (10 pts)
Theory
Problem S10 (10 pts)
Theory
Problem S11 (10 pts)
Theory
Problem S12 (10 pts)
Theory
Problem S13 (10 pts)
Theory
Problem S14 (10 pts)
Theory
Problem S15 (10 pts)
Theory
Problem L1 (50 pts)
Theory
Problem L2 (50 pts)
Theory
Problem L3 (50 pts)
Theory
Data Analysis
Data Analysis Solutions Data Analysis Results
Problem D1 (24.5 pts)
Data Analysis
Problem D2 (32.5 pts)
Data Analysis
Problem D3 (18 pts)
Data Analysis
Problem D4 (75 pts)
Data Analysis
2012 Rio de Janeiro, Brazil
Theory
Theory Problems Theory Results
Problem S1 (10 pts)
Theory
Problem S2 (10 pts)
Theory
Problem S3 (10 pts)
Theory
Problem S4 (10 pts)
Theory
Problem S5 (10 pts)
Theory
Problem S6 (10 pts)
Theory
Problem S7 (10 pts)
Theory
Problem S8 (10 pts)
Theory
Problem S9 (10 pts)
Theory
Problem S10 (10 pts)
Theory
Problem S11 (10 pts)
Theory
Problem S12 (10 pts)
Theory
Problem S13 (10 pts)
Theory
Problem S14 (10 pts)
Theory
Problem S15 (10 pts)
Theory
Problem L1 (30 pts)
Theory
Problem L2 (30 pts)
Theory
Data Analysis
Data Analysis Problems Data Analysis Results
Problem D1
Data Analysis
Problem D2
Data Analysis
2011 Silesia, Poland
Theory
Theory Problems
Problem S1 (10 pts)
Theory
Problem S2 (10 pts)
Theory
Problem S3 (10 pts)
Theory
Problem S4 (10 pts)
Theory
Problem S5 (10 pts)
Theory
Problem S6 (10 pts)
Theory
Problem S7 (10 pts)
Theory
Problem S8 (10 pts)
Theory
Problem S9 (10 pts)
Theory
Problem S10 (10 pts)
Theory
Problem S11 (10 pts)
Theory
Problem S12 (10 pts)
Theory
Problem S13 (10 pts)
Theory
Problem S14 (10 pts)
Theory
Problem S15 (10 pts)
Theory
Problem L1 (30 pts)
Theory
Problem L2 (30 pts)
Theory
Problem L3 (30 pts)
Theory
Data Analysis
Data Analysis Problems
Problem D1 (25 pts)
Analysis of times of minima Data Analysis
Problem D2 (25 pts)
Weighing a galaxy Data Analysis
2010 Beijing, China
Theory
Theory Solutions
Problem S1 (10 pts)
Theory
Problem S2 (10 pts)
Theory
Problem S3 (10 pts)
Theory
Problem S4 (10 pts)
Theory
Problem S5 (10 pts)
Theory
Problem S6 (10 pts)
Theory
Problem S7 (10 pts)
Theory
Problem S8 (10 pts)
Theory
Problem S9 (10 pts)
Theory
Problem S10 (10 pts)
Theory
Problem S11 (10 pts)
Theory
Problem S12 (10 pts)
Theory
Problem S13 (10 pts)
Theory
Problem S14 (10 pts)
Theory
Problem S15 (10 pts)
Theory
Problem L1 (30 pts)
Theory
Problem L2 (30 pts)
Theory
Data Analysis
Data Analysis Problems Data Analysis Solutions
Problem D1 (35 pts)
CCD Image Data Analysis
Problem D2 (35 pts)
Light curves of stars Data Analysis
2009 Tehran, Iran
Theory
Theory Problems Theory Solutions
Problem S1 (10 pts)
Theory
Problem S2 (10 pts)
Theory
Problem S3 (10 pts)
Theory
Problem S4 (10 pts)
Theory
Problem S5 (10 pts)
Theory
Problem S6 (10 pts)
Theory
Problem S7 (10 pts)
Theory
Problem S8 (10 pts)
Theory
Problem S9 (10 pts)
Theory
Problem S10 (10 pts)
Theory
Problem S11 (10 pts)
Theory
Problem S12 (10 pts)
Theory
Problem S13 (10 pts)
Theory
Problem S14 (10 pts)
Theory
Problem S15 (10 pts)
Theory
Problem L1 (45 pts)
High Altitude Projectile Theory
Problem L2 (45 pts)
Apparent number density of stars in the Galaxy Theory
Data Analysis
Data Analysis Problems Data Analysis Solutions
Problem D1 (60 pts)
CCD Image Processing Data Analysis
Problem D2 (60 pts)
Venus Data Analysis
2008 Bandung, Indonesia
Theory
Theory Problems Theory Solutions
Problem S1 (20 pts)
Theory
Problem S2 (20 pts)
Theory
Problem S3 (20 pts)
Theory
Problem S4 (20 pts)
Theory
Problem S5 (20 pts)
Theory
Problem S6 (20 pts)
Theory
Problem S7 (20 pts)
Theory
Problem S8 (20 pts)
Theory
Problem S9 (20 pts)
Theory
Problem S10 (20 pts)
Theory
Problem S11 (20 pts)
Theory
Problem S12 (10 pts)
Theory
Problem S13 (20 pts)
Theory
Problem S14 (20 pts)
Theory
Problem S15 (20 pts)
Theory
Problem L1 (100 pts)
Theory
Problem L2 (100 pts)
Theory
Problem L3 (100 pts)
Theory
Data Analysis
Data Analysis Problems
Problem D1 (100 pts)
Virgo Cluster Data Analysis
Problem D2 (100 pts)
Determination of stellar masses in a visual binary system Data Analysis
Problem D3 (100 pts)
The Age of Meteorite Data Analysis
2007 Chiang Mai, Thailand
Theory
Theory Problems Theory Solutions Theory Results
Problem T1 (30 pts)
Theory
Problem T2 (10 pts)
Theory
Problem T3 (10 pts)
Theory
Problem T4 (10 pts)
Theory
Data Analysis
Data Analysis Problems Data Analysis Solutions Data Analysis Results
Problem D1 (4 pts)
Galilean moons Data Analysis
Problem D2 (8 pts)
The Moon's age Data Analysis
Problem D3 (8 pts)
Solar System objects Data Analysis