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Links to the current IB specifications

Topic 11: Wave phenomena

11.2.1 Describe what is meant by the Doppler effect

E2 Stellar radiation and stellar types

E.2.7 Explain how atomic spectra may be used to deduce chemical and physical data for stars.

E4 Cosmology E.4.3 Suggest that the red-shift of light from galaxies indicates that the universe is expanding.

E6 Galaxies and the expanding universe

E.6.2 Explain the red-shift of light from distant galaxies

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A new planetary system

At least five planets (exoplanets) have been found orbiting starHD 10180, 127 light years away.

Astronomers have discovered a new planetary system that is the largest ever found and very similar to our Solar System.

It is very difficult to observe exoplanets directly. They are small, don’t produce their own light, and are often hidden by their host star’s light.

Astronomers therefore use indirect methods to detect them.One common method is radial velocity tracking.

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Exoplanet hunting

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Red shift and the Doppler effect