HD209458 b: Reading a scientific paper

Subject:

The first exoplanet to be discovered using the transit method was HD 209458 b. This discovery is
presented in an article. Does this article accurately describe the discovery? Does it help us understand
the method and the significance of this discovery?

Level: High school
Time: approximately 2 hours

Prerequisites:

• Kepler’s third laws
• Barycentre
• The Doppler effect
• Methods for detecting exoplanets : Radial velocities

Objectives:

• Read an article published in Science et vie, reporting the first observation of the transit of an extrasolar planet, HD 209458b.
• In this article, certain physical concepts are deliberately simplified. The aim is to identify them clearly and to calculate the various results and facts given in the article.

Equipment required:

• Calculator.

Subject, Appendices and correction:

• Subject
• Appendices : article "We’ve finally seen an extrasolar planet"
• Appendices : data on the planets of the Solar System
• correction

Author : Alain Doressoundiram, LIRA/UFE, Observatoire de Paris