Doppler Shift Interactive¶

This interactive allows you to see how the spectrum of a star is affected by the presense of another object orbiting it, causing the star to move, and therefore for its lines to shift in wavelength.

Interactive Figure 1: Doppler Shift versus Radial Velocity¶

This first figure show the spectrum of a hydrogen cloud in space versus the labratory spectrum of hydrogen gas. The slider on the right hand side lets you adjust the hydrogen cloud's radial veleocity, that is, its speed directly towards, or away from, us.

Interactive Figure 2: Spectrum of a Moving Stellar System¶

The following interactive let's you simulate the expected spectrum from

• a binary star system where both stars have visible hydrogen absorption lines and
• an exoplanetary system where both objects have hydrogen in their spectra, but only the star's spectral lines are visible because the exoplanet's spectrum is much too faint to see.