International Astronomy Olympiad (IAO)

International Olympiad on Astronomy and Astrophysics (IOAA)

Extensive material in basic astronomical ideas is required in both theoretical and practical problems. To solve the problems, you’ll need a high school level understanding of physics and maths. Standard solutions should not include calculus, complicated numbers, or solving differential equations. Astronomical software packages could help with practical and observational problems.

The National Standard Examination in Astronomy (NSEA) syllabus for Classes XI and XII is very similar to CBSE Physics. The NSEA does not provide a detailed syllabus, thus this is just a basic guideline.

The syllabus for the Indian National Physics Olympiad (INPhO) is largely similar to that of the NSEA.

The syllabus, on the other hand, is merely a suggestion. Similar to International Olympiads, National Olympiad questions and problems are often non-traditional and of a high difficulty level.


General Notes

Extensive contents in basic astronomical concepts are required for theoretical and practical problems.

Basic concepts in physics and mathematics at the high school level are required in solving the problems. Standard solutions should not involve the use of calculus and/or the use of complex numbers and/or solving differential equations.

Astronomical software packages may be used in practical and observational problems. The contestants will be informed the list of software packages to be used at least 3 months in advance. The chosen software packages should be preferably freewares or low-cost ones enabling all countries to obtain them easily for practice purposes. The chosen software should preferably be available on multiple OSs (Windows / Unix / GNU-Linux / Mac).

Concepts and phenomena not included in the Syllabus may be used in questions but sufficient information must be given in the questions so that contestants without previous knowledge of these topics would not be at a disadvantage.

Sophisticated practical equipments likely to be unfamiliar to the candidates should not dominate a problem. If such devices are used in the questions, sufficient information must be provided. In such cases, students should be given the opportunity to familiarise themselves with such equipments.

The original texts of the problems have to be set in the SI units, wherever applicable. Participants will be expected to mention appropriate units in their answers and should be familiar with the idea of correct rounding off and expressing the final result(s) and error(s) with a correct number of significant digits.

Theoretical Part

Symbol (Q) is attached to some topics in the list. It means “qualitative understanding only”. Quantitative reasoning/proficiency in these topics are not mandatory.

The following theoretical contents are proposed for the contestants.

Basic Astrophysics

Celestial Mechanics: Newton’s Laws of Gravitation, Kepler’s Laws For Circular and Non-circular Orbits, Roche Limit, Barycentre, 2-body Problem, Lagrange Points

Electromagnetic Theory & Quantum Physics: Electromagnetic Spectrum, Radiation Laws, Blackbody Radiation

Thermodynamics: Thermodynamic Equilibrium, Ideal Gas, Energy Transfer

Spectroscopy and Atomic Physics: Absorption, Emission, Scattering, Spectra of Celestial Objects, Doppler Effect, Line Formations, Continuum Spectra, Splitting and Broadening of Spectral Lines, Polarisation

Nuclear Physics: Basic Concepts Including Structure of an Atom, Mass Defect and Binding Energy Radioactivity, Neutrinos (Q).

Coordinates and Times

Celestial Sphere: Spherical Trigonometry, Celestial Coordinates and Their Applications, Equinox and Solstice, Circumpolar Stars, Constellations and Zodiac.

Concept of Time: Solar Time, Sidereal Time, Julian Date, Heliocentric Julian Date, Time Zone, Universal Time, Local Mean Time, Different Definitions of “Year”, Equation of Time

Solar System

The Sun: Solar Structure, Solar Surface Activities, Solar Rotation, Solar Radiation and Solar Constant, Solar Neutrinos (Q), Sun-earth Relations, Role of Magnetic Fields (Q), Solar Wind and Radiation Pressure, Heliosphere (Q), Magnetosphere (Q).

The Solar System: Earth-moon System, Precession, Nutation, Libration, Formation and Evolution of The Solar System (Q), Structure And Components of The Solar System (Q), Structure and Orbits of The Solar System Objects, Sidereal and Synodic Periods, Retrograde Motion, Outer Reaches of The Solar System (Q).

Space Exploration: Satellite Trajectories and Transfers, Human Exploration of The Solar System (Q), Planetary Missions (Q), Sling-shot Effect of Gravity, Space-based Instruments (Q).

Phenomena: Tides, Seasons, Eclipses, Aurorae (Q), Meteor Showers.


Stellar Properties: Methods of Distance Determination, Radiation, Luminosity and Magnitude, Color Indices and Temperature, Determination of Radii and Masses, Stellar Motion, Irregular and Regular Stellar Variabilities – Broad Classification & Properties, Cepheids & Period-luminosity Relation, Physics of Pulsation (Q).

Stellar Interior and Atmospheres: Stellar Equilibrium, Stellar Nucleosynthesis, Energy Transportation (Q), Boundary Conditions, Stellar Atmospheres and Atmospheric Spectra.

Stellar Evolution: Stellar Formation, Hertzsprung-Russell Diagram, Pre-main Sequence, Main Sequence, Post-main Sequence Stars, Supernovae, Planetary Nebulae,  End Stage of Stars.

Stellar Systems

Binary Star Systems: Different Types of Binary Stars, Mass Determination In Binary Star Systems, Light and Radial Velocity Curves of Eclipsing Binary Systems, Doppler Shifts In Binary Systems, Interacting Binaries, Peculiar Binary Systems.

Exoplanets: Techniques Used to Detect Exoplanets.

Star Clusters: Classification and Structure, Mass, Age, Luminosity and Distance Determination.

Milky Way Galaxy: Structure and Composition, Rotation, Satellites of Milky Way (Q).

Interstellar Medium: Gas (Q), Dust (Q), Hii Regions, 21cm Radiation, Nebulae (Q), Interstellar Absorption, Dispersion Measure, Faraday Rotation.

Galaxies: Classifications Based on Structure, Composition and Activity, Mass, Luminosity and Distance Determination, Rotation Curves.

Accretion Processes: Basic Concepts (Spherical and Disc Accretion) (Q), Eddington Luminosity.


Elementary Cosmology: Expanding Universe and Hubble’s Law, Cluster of Galaxies, Dark Matter, Dark Energy (Q), Gravitational Lensing, Cosmic Microwave Background Radiation, Big Bang (Q), Alternative Models of The Universe (Q), Large Scale Structure (Q), Distance Measurement At a Cosmological Scale, Cosmological Redshift.

Instrumentation and Space Technologies

Multi-wavelength Astronomy: Observations In Radio, Microwave, Infrared, Visible, Ultraviolet, X-ray, and Gamma-ray Wavelength Bands, Earth’s Atmospheric Effects.

Instrumentation: Telescopes and Detectors (E.G. Charge-coupled Devices, Photometers, Spectrographs), Magnification, Focal Length, Focal Ratio, Resolving and Light-gathering Powers of Telescopes, Geometric Model of Two Element Interferometer, Aperture Synthesis, Adaptive Optics, Photometry, Astrometry.


Practical Part

This part consists of 2 sections: observations and data analysis sections. The theoretical part of the Syllabus provides the basis for all problems in the practical part.

The observations section focuses on contestant’s experience in naked-eye observations, usage of sky maps and catalogues, application of coordinate systems in the sky, magnitude estimation, estimation of angular separation usage of basic astronomical instruments-telescopes and various detectors for observations but enough instructions must be provided to the contestants. Observational objects may be from real sources in the sky or imitated sources in the laboratory. Computer simulations may be used in the problems but sufficient instructions must be provided to the contestants.

The data analysis section focuses on the calculation and analysis of the astronomical data provided in the problems. Additional requirements are as follows:

Proper identification of error sources, calculation of errors, and estimation of their influence on the final results. Proper use of graph papers with different scales, e.g., polar and logarithmic papers. Transformation of the data to get a linear plot and finding “Best Fit” line approximately. Basic statistical analysis of the observational data. Knowledge of the most common experimental techniques for measuring physical quantities mentioned in Part A.




Last Updated on January 21, 2023 by Sonkamble Satish