Who discovered 51 Pegasi b?

Edwin Hubble and Milton Humason

How was the planet detected?

By the wobble of its star in spectra

51 Pegasi b Quiz: The First Exoplanet Around a Sun-Like Star

Astronomers did not expect a giant planet to circle its star in just four days, and this 51 Pegasi b quiz explains why the 1995 discovery changed astronomy. Play 10 interactive questions on Michel Mayor and Didier Queloz, the radial velocity method, Haute-Provence Observatory, the name Dimidium and the earlier pulsar planets.

Start 51 Pegasi b Quiz

🎯 Daily Trivia Challenge • 🧠 10 Questions • ⏱️ 150 Seconds

Question 1 / 10 Time: 150s

Year
In which year was 51 Pegasi b announced?
Discoverers
Who discovered 51 Pegasi b?
Nobel
Which prize did the discoverers share in 2019?
Method
How was the planet detected?
Observatory
At which French observatory was the discovery made?
Orbit
How long does 51 Pegasi b take to orbit its star?
Type
What new class of planet did it reveal?
Name
What official name was 51 Pegasi b given in 2015?
Constellation
In which constellation is the star 51 Pegasi?
Earlier
Which planets were found before 1995, around a different kind of star?

Explanations: answer key for all 10 questions

Q1: In which year was 51 Pegasi b announced?
Answer: 1995
It was the first planet found orbiting a Sun-like star.
Q2: Who discovered 51 Pegasi b?
Answer: Michel Mayor and Didier Queloz
The Swiss astronomers worked at the University of Geneva.
Q3: Which prize did the discoverers share in 2019?
Answer: Nobel Prize in Physics
They shared it with cosmologist James Peebles.
Q4: How was the planet detected?
Answer: By the wobble of its star in spectra
The radial velocity method measures tiny Doppler shifts as the planet tugs its star.
Q5: At which French observatory was the discovery made?
Answer: Haute-Provence Observatory
They used the ELODIE spectrograph there.
Q6: How long does 51 Pegasi b take to orbit its star?
Answer: About 4.2 days
Its tiny orbit surprised astronomers who expected giants far out like Jupiter.
Q7: What new class of planet did it reveal?
Answer: Hot Jupiters
Hot Jupiters are gas giants orbiting very close to their stars.
Q8: What official name was 51 Pegasi b given in 2015?
Answer: Dimidium
Dimidium is Latin for half, referring to its mass of about half Jupiter's; the star was named Helvetios.
Q9: In which constellation is the star 51 Pegasi?
Answer: Pegasus
The star is about 50 light-years away and faintly visible to the naked eye under dark skies.
Q10: Which planets were found before 1995, around a different kind of star?
Answer: Planets orbiting a pulsar
In 1992 Aleksander Wolszczan and Dale Frail found planets around pulsar PSR B1257+12.

51 Pegasi B Quiz – The Planet That Started It All

In 1995, Michel Mayor and Didier Queloz of the University of Geneva announced a planet orbiting 51 Pegasi, a Sun-like star about 50 light-years away in the constellation Pegasus.

They used the radial velocity method at Haute-Provence Observatory, measuring how the star wobbles as the planet pulls on it. The planet, about half Jupiter's mass, orbits in just 4.2 days, creating the category of hot Jupiters.

The discovery opened the age of exoplanet research, which has now found thousands of worlds. In 2015 the planet was named Dimidium and the star Helvetios, and in 2019 Mayor and Queloz shared the Nobel Prize in Physics.

What This Quiz Teaches

Space fans and students will enjoy these questions.

When and how the planet was found
Who found it
Why its orbit surprised scientists
What its official name is
Which planets came earlier

Did You Know?

Hot Jupiters may migrate inward after forming.
More than 5,000 exoplanets are now confirmed.
Queloz later worked at Cambridge.
The ELODIE spectrograph was built for precise velocities.
51 Pegasi is slightly older than the Sun.