In 1992, almost 30 years ago, astronomers discovered the first-ever exoplanets around a pulsar called PSR B1257+12. In a new study, astronomers revealed that such planets might be extremely rare.
Astronomers reached this conclusion after surveying 800 pulsars, followed by the Jodrell Bank Observatory over the last 50 years. The survey revealed that the first exoplanet discovery might be extraordinarily uncommon: less than 0.5% of all known pulsars could host Earth-mass planets.
Since the first discovery, several pulsars have been found to host planets. However, the extremely violent conditions surrounding the births and lives of pulsars make ‘normal’ planet formation unlikely. Many detected planets are exotic objects (such as those made mostly of a diamond), unlike those we know in our Solar System.
The scientists specifically searched for signs of planets with companions that have masses up to 100 times that of the Earth and orbital periods of 20 days to 17 years. The system PSR J2007+3120, which may include at least two planets with masses a few times that of the Earth and orbital periods of 1.9 and 3.6 years, is the most promising of the ten possible detections.
Luliana Nițu, a Ph.D. student at the University of Manchester, said, “The work results indicate no bias for particular planet masses or orbital periods in pulsar systems. However, the results yield information on the shape of these planets’ orbits. In contrast to the near-circular orbits found in our Solar System, these planets would orbit their stars on highly elliptical paths. This indicates that pulsar-planet systems‘ formation process is vastly different from traditional star-planet systems.”
The work was presented at the National Astronomy Meeting (NAM 2022).