PSR B1257+12 planets
First confirmed exoplanets, orbiting a pulsar.
The PSR B1257+12 planets, named Draugr, Poltergeist, and Phobetor, are the first confirmed extrasolar planets ever discovered. Their discovery in 1992 and 1994 revolutionized astronomy by proving that planets can exist outside the Solar System and around a stellar remnant.
- discovered
- 1992 (Poltergeist, Phobetor); 1994 (Draugr)
- host_star
- PSR B1257+12 (Lich)
- type
- Pulsar planets
- number_confirmed
- 3
- lowest_mass_planet
- Draugr (less than twice the mass of Earth's moon)
- first_extrasolar_planets
- True
- first_pulsar_planets
- True
Lore & Background
The planets were discovered by Polish astronomer Aleksander Wolszczan using the Arecibo radio telescope. In 1992, Wolszczan and Dale Frail published a paper announcing two planets (Poltergeist and Phobetor) orbiting the millisecond pulsar PSR B1257+12. A third planet, Draugr, was found in 1994. The planets were initially designated PSR 1257+12 A, B, and C, ordered by increasing distance. Later, the IAU assigned the names Draugr, Poltergeist, and Phobetor through the NameExoWorlds campaign in December 2015.
Reader's Guide
The PSR B1257+12 planets are historically significant as the first confirmed exoplanets, proving that planetary systems can exist beyond the Solar System. Their discovery around a pulsar—a rapidly spinning neutron star—was unexpected, as astronomers had assumed planets only form around main-sequence stars. The planets are believed to have formed from a disk of material resulting from the merger of two white dwarfs, which created the pulsar. This system also sparked a search for other pulsar planets, though only a handful have been confirmed. The planets' naming convention—using lower-case Roman letters from 'b'—became the standard for exoplanets. Draugr remains the lowest-mass planet discovered by any observational technique, with less than twice the mass of Earth's moon.
Did You Know?
- The planets were the first extrasolar planets and first pulsar planets ever discovered.
- Draugr has less than twice the mass of Earth's moon, making it the lowest-mass planet discovered by any observational technique.
Frequently Asked Questions
Why are the PSR B1257+12 planets so important to astronomy?
Because they were the very first exoplanets ever confirmed to exist, their detection shattered the assumption that planets could only form around ordinary stars and launched the entire field of exoplanet science.
How many planets orbit PSR B1257+12 and what are their names?
Three worlds have been confirmed: Draugr, Poltergeist, and Phobetor, with Draugr being the lightest at under twice the mass of Earth's Moon.
When were the PSR B1257+12 planets discovered?
Poltergeist and Phobetor were identified in 1992, while the innermost planet Draugr was confirmed two years later in 1994.
What kind of star do the PSR B1257+12 planets orbit?
Their host, PSR B1257+12 (Lich), is a millisecond pulsar—a rapidly spinning stellar remnant—making these the first known planets to survive around a dead star rather than a living one.
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