Exoplanets and Detection Methods – Fundamentals and Principles
How it works
Exoplanets are planets outside our solar system that orbit other stars. They are detected using various methods. In the transit method, the observed brightness of a star decreases slightly when a planet passes in front of it. In the radial velocity method, the motion of the star is detected from the Doppler effect in its spectral lines. Astrometry measures small changes in the star’s position in the sky. Direct imaging attempts to make the planet itself visible, usually in the infrared and with special techniques, because the star is much brighter. In the gravitational lensing method, the light of a background star is temporarily magnified by the gravity of a foreground system. Each method has advantages and disadvantages and is differently well suited to certain types of planets and star systems.
Many exoplanets are detected indirectly because they are very faint compared with their stars. The transit method, radial velocity method, and astrometry measure the effects of the planet on observable properties of its star. Direct imaging shows the planet itself, and the gravitational lensing method uses the deflection of the light of a background star.
An example
What does the transit method show when detecting an exoplanet?
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50 Exercises
To the learning unit →Own explanation and own practice exercises by AmyMath. Subject reference framework: Astronomy. The topic assignment may vary by federal state.