wunder beta📘 How astronomers found the first exoplanet
In 1995, Mayor and Queloz did not photograph a planet. They measured 51 Pegasi's repeating wobble: an invisible companion moving the star toward us, then away.
What you’ll learn
- A star that would not sit stillExplain why the first exoplanet around a Sun-like star was inferred from a host star's motion.A hidden planet revealed itself through a repeating gravitational wobble in 51 Pegasi.
- Turning starlight into motionDescribe how Doppler shifts and radial velocity turn spectral lines into an orbital measurement.ELODIE transformed tiny wavelength changes into a testable four-day curve.
- The announcement that changed the mapPlace 51 Pegasi b in the history of exoplanet discovery and planetary formation theory.The 1995 announcement introduced the hot Jupiter and clarified what “first” meant.
- From one wobble to thousands of worldsTrace how confirmation and complementary techniques made exoplanet discovery a field.One surprising signal became a general method for finding and comparing distant worlds.
Questions this course answers
What did Mayor and Queloz measure to find 51 Pegasi b?
The planet was inferred from the host star's repeating toward-and-away motion, measured through shifts in spectral lines.
Why did 51 Pegasi b's four-day orbit help the discovery?
A short period let astronomers see the velocity pattern repeat over only a few nights.
What does a spectrograph detect in the radial-velocity method?
Motion toward or away from Earth shifts the wavelengths of the star's spectral fingerprints.
In what sense was 51 Pegasi b the first exoplanet?
Pulsar planets were found earlier, but 51 Pegasi b was the landmark confirmation around a solar-type main-sequence star.
Why was an independent observation from Lick Observatory important?
A second team finding the same rapid variation reduced the chance that ELODIE's result was an instrumental artifact.
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