9.3.4

Detecting Exoplanets

Test yourself

Detecting Exoplanets

Detecting planets around stars other than the Sun was a huge development in 20th Century Astrophysics.

Illustrative background for Very faint signalIllustrative background for Very faint signal ?? "content

Very faint signal

  • Exoplanets are very faint compared with their star and are also very close to them.
  • Techniques for observing exoplanets are currently in their infancy.
Illustrative background for Transit methodIllustrative background for Transit method ?? "content

Transit method

  • By observing how the light intensity of the star changes over time, sufficiently sensitive detectors can distinguish when an exoplanet passes in front of its star.
  • The light intensity dips for a short period in a very regular and periodic way, as shown in the diagram.
Illustrative background for Light curveIllustrative background for Light curve ?? "content

Light curve

  • This type of diagram known as a light curve.
  • It shows how the brightness of a star varies with time.
Illustrative background for Radial velocity methodIllustrative background for Radial velocity method ?? "content

Radial velocity method

  • The presence of a large, closely orbiting exoplanet causes the host star to wobble in a periodic and regular way, changing its radial velocity.
  • The wobble causes the light from the star to be affected by Doppler shift.
  • Observing the spectral lines of the star and how they shift periodically implies the existence of an exoplanet.

Jump to other topics

1Measurements & Errors

2Particles & Radiation

3Waves

4Mechanics & Materials

5Electricity

6Further Mechanics & Thermal Physics (A2 only)

7Fields & Their Consequences (A2 only)

8Nuclear Physics (A2 only)

9Option: Astrophysics (A2 only)

10Option: Medical Physics (A2 only)

11Option: Engineering Physics (A2 only)

12Option: Turning Points in Physics (A2 only)

Go student ad image

Unlock your full potential with GoStudent tutoring

  • Affordable 1:1 tutoring from the comfort of your home

  • Tutors are matched to your specific learning needs

  • 30+ school subjects covered

Book a free trial lesson