Planets found by pulsar timing
8 of the confirmed exoplanets in this catalog, 0.1% of the total, were found by pulsar timing: reading a dead star's clock for the nudge of an orbiting world, the first of them in 1992.
A pulsar is the collapsed core of an exploded star, spinning tens or hundreds of times a second and sweeping a beam past Earth with a regularity that rivals an atomic clock. Anything orbiting it shifts the arrival time of those pulses by microseconds in a repeating pattern, and because the clock is so precise, the method can weigh planets a fiftieth of Earth's mass.
This is where the whole field began. In 1992 Aleksander Wolszczan and Dale Frail reported planets around PSR B1257+12, three years before the first planet around a Sun-like star. The worlds themselves are almost certainly a second generation, condensed out of the debris of the supernova, orbiting a stellar corpse in a bath of radiation.
There are very few pulsars, and fewer still timed precisely enough. The method is the most sensitive we have and it applies to a vanishingly small number of stars, which is why it accounts for a handful of the planets in this catalog and always will.
| # | World | Distance | Discovered |
|---|---|---|---|
| 1 | PSR J2322-2650 b | 750 ly | 2017 |
| 2 | PSR B0329+54 b | 1,647 ly | 2017 |
| 3 | PSR B1257+12 b | 1,957 ly | 1994 |
| 4 | PSR B1257+12 c | 1,957 ly | 1992 |
| 5 | PSR B1257+12 d | 1,957 ly | 1992 |
| 6 | PSR J1719-1438 b | 3,914 ly | 2011 |
How were planets found around a pulsar?
8 of the confirmed exoplanets in this catalog, 0.1% of the total, were found by pulsar timing: reading a dead star's clock for the nudge of an orbiting world, the first of them in 1992.
What was the first planet found by pulsar timing?
PSR B1257+12 c, confirmed in 1992. The method has found 8 confirmed worlds since, the most recent of them in 2024.
What can this method not see?
There are very few pulsars, and fewer still timed precisely enough. The method is the most sensitive we have and it applies to a vanishingly small number of stars, which is why it accounts for a handful of the planets in this catalog and always will.
Were the first exoplanets really found around a pulsar?
Yes. The 1992 detection around PSR B1257+12 predates 51 Pegasi b by three years. The pulsar planets are the first confirmed exoplanets; 51 Pegasi b is the first around a normal star.
Could anything live on a pulsar planet?
Effectively no. A pulsar bathes its surroundings in X-rays and relativistic particles, and the planets receive no visible starlight to speak of. They are among the most hostile places this catalog holds.
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