Q 01/05

What is an exoplanet?

A) A planet outside the Solar System

B) A planet orbiting beyond Neptune

C) A dwarf planet in the asteroid belt

D) A large moon of a gas giant

Answer · why

A) A planet outside the Solar System

More than 6,300 have been confirmed as of mid-2026, in over 4,700 systems.

Q 02/05

Around what kind of object were the first confirmed exoplanets found in 1992?

A) A white dwarf

B) A pulsar

C) A red dwarf

D) A Sun-like star

Answer · why

B) A pulsar

Aleksander Wolszczan and Dale Frail found two terrestrial-mass planets orbiting PSR B1257+12.

Q 03/05

Which two astronomers announced the first exoplanet around a Sun-like star, 51 Pegasi b, in October 1995?

A) Marcy and Butler

B) Charbonneau and Brown

C) Michel Mayor and Didier Queloz

D) Wolszczan and Frail

Answer · why

C) Michel Mayor and Didier Queloz

They worked at the Observatoire de Haute-Provence and shared a 2019 Nobel Prize.

Q 04/05

What official proper name did the IAU give 51 Pegasi b?

A) Bellerophon

B) Janssen

C) Draugr

D) Dimidium

Answer · why

D) Dimidium

It is Latin for 'half', for the planet's roughly half-Jupiter mass.

Q 05/05

51 Pegasi b is the prototype of which class of exoplanet?

A) Hot Jupiters

B) Super-Earths

C) Mini-Neptunes

D) Rogue planets

Answer · why

A) Hot Jupiters

Gas giants orbiting scorchingly close to their stars turned out to be common among early discoveries.