International Olympiad on Astronomy and Astrophysics Junior

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

2025 Piatra-Neamț, Romania

Theory

Theory Solutions

Problem T1 (10 pts)

Binary System Theory

Problem T2 (10 pts)

Speed of Asteroid Theory

Problem T3 (10 pts)

Where is Theodor Theory

Problem T4 (10 pts)

Exploring NEAs Theory

Problem T5 (15 pts)

Ceahlǎu Mountain Theory

Problem T6 (15 pts)

The Flying Aquilla Theory

Problem T7 (30 pts)

Lunar Eclipse Theory

Problem T8 (40 pts)

Roche Limit, Hill Sphere, Lagrange Points Theory

Problem T9 (40 pts)

Lightcurves Theory

Observation

Sky Map Solutions Telescope Solutions

Problem OM1 (40 pts)

Know your sky Sky Map

Problem OM2 (10 pts)

Chart and time Sky Map

Problem OM3 (10 pts)

Missing stars Sky Map

Problem OT1 (4 pts)

Telescope

Problem OT2 (9 pts)

Telescope

Problem OT3 (20 pts)

Telescope

Problem OT4 (27 pts)

Telescope

2024 Kathmandu, Nepal

Theory

Theory Problems

Problem T1 (15 pts)

Theory

Problem T2 (15 pts)

Theory

Problem T3 (15 pts)

Theory

Problem T4 (15 pts)

Theory

Problem T5 (15 pts)

Theory

Problem T6 (15 pts)

Theory

Problem T7 (15 pts)

Theory

Problem T8 (15 pts)

Theory

Problem T9 (15 pts)

Theory

Problem T10 (15 pts)

Theory

Problem T11 (15 pts)

Theory

Problem T12 (15 pts)

Theory

Observation

Sky Chart Problems Telescope Problems

Problem OC1 (43.5 pts)

Sky Chart

Problem OC2 (13.5 pts)

Sky Chart

Problem OC3 (18 pts)

Sky Chart

Problem OT1 (32 pts)

The Moon Telescope

Problem OT2 (16 pts)

Telescope

2023 Volos, Greece

Theory

Theory Problems Theory Solutions

Problem T1 (10 pts)

Horizon crossing Theory

Problem T2 (10 pts)

Planet orbits Theory

Problem T3 (10 pts)

Unresolved binary star Theory

Problem T4 (10 pts)

Rapidly spinning neutron star Theory

Problem T5 (10 pts)

Moon phases Theory

Problem T6 (10 pts)

Solar eclipse Theory

Problem T7 (10 pts)

Parallax and proper motion Theory

Problem T8 (10 pts)

Telescope Theory

Problem T9 (10 pts)

Cosmology Theory

Problem T10 (10 pts)

H-R Diagram Theory

Problem T11 (40 pts)

SIRIUS A and B Theory

Problem T12 (40 pts)

SATELLITES Theory

Observation

Telescope Problems

Problem OM1 (45 pts)

Navigating the night sky Sky Map

Problem

Problem OM2 (45 pts)

Navigating the night sky Sky Map

Problem

Problem OT1 (45 pts)

Sun Observations Telescope

Problem OT2 (45 pts)

Cloud Sky Observation Telescope

2022 Câmpulung Moldovenesc, Romania

Theory

Theory Problems

Problem T1 (10 pts)

The stars observed with the telescope Theory

Solution

Problem T2 (10 pts)

The Sun on the Horizon Theory

Solution

Problem T3 (10 pts)

The escape velocity Theory

Solution

Problem T4 (10 pts)

The Terrestrial Satellite Theory

Solution

Problem T5 (10 pts)

Andromeda Galaxy Rotation Theory

Solution

Problem T6 (10 pts)

The Sun as seen from Saturn Theory

Solution

Problem T7 (10 pts)

Balls Suspended inside a Terrestrial Satellite Theory

Solution

Problem T8 (10 pts)

Spaceship to the Sun Theory

Solution

Problem T9 (10 pts)

The Moon, seen on the way to the Moon Theory

Solution

Problem T10 (10 pts)

The luminosity of a star Theory

Solution

Problem T11 (100 pts)

Zodiac IOAA-J-2022 Theory

Problem Solution

Problem T12 (100 pts)

The rocket that destroys the threatening asteroid Theory

Problem Solution

Observation

Night Observation Problems

Problem OM (45 pts)

Sky Map Sky Map

Problem Solution

Problem OT1

Observations with naked eye Night Observation

Problem OT2

Observations using the astronomical telescope Night Observation