In 1992, two astronomers, Alexander Welchon and Del Friel, published a paper in Nature announcing the discovery of the first exoplanets, according to RT.
They were two rocky worlds, 4.3 and 3.9 times the mass of Earth, orbiting a type of dead star known as a millisecond pulsar, called PSR B1257+12, or Lich for short. A third exoplanet, 0.2 times the mass of Earth, was confirmed to orbit the pulsar in 1994.
An analysis of hundreds of pulsars has now revealed that such exoplanets are incredibly rare – and almost disappearing, and pulsars are also very rare (only about 3,320 are known in the Milky Way at the time of writing), and among them, astronomers say, Less than 0.5% are likely to have rocky, Earth-like worlds in orbit, and that’s just 16 pulsars.
Millisecond pulsars are even rarer, with about 550 known stars in the Milky Way, and that makes the first human discoveries of exoplanets so amazing. All dead stars are pretty cool, but pulsars add a little kick to the interesting factor. It is a type of neutron star.
This is the core of a dead star that has reached the end of its atomic fusion period, expelled most of its outer matter, and collapsed into a body whose density does not exceed only black holes, and the mass of neutron stars can reach about 2.3 times the mass of the sun, packed into a ball with a diameter of 20 kilometers (12 miles). ) Just.
A pulsar is defined as a rotating neutron star that has beams of radiation emanating from its poles, and this is its direction. When the pulsar rotates, its beams sweep the Earth, making the star appear to be pulsing. Photovoltaics also occur on millisecond scales.
This is a very harsh environment, and it could have exoplanets; Since the discovery of Lich and his worlds, a few other pulsars have been discovered with exoplanets, however, most of these are giants, and those that can’t get a bit weird, like a super-dense world thought to be the remnants of a white dwarf star decimated by the star. pulsating;
A team of astronomers led by Juliana New, from the University of Manchester in the United Kingdom, wanted to discover how common pulsars are, and conducted a survey of 800 pulsars monitored by the Jodrell Bank Observatory in the United Kingdom, looking for light signals in the timing of the pulsations that might indicate the presence of planets. outer orbit around the solar system.
New said: “Pulsars are incredibly interesting and strange things. Exactly 30 years ago, the first exoplanets were discovered around a pulsar, but we do not yet understand how these planets can form and live in such extreme conditions. How common these planets are, and what they look like is a crucial step toward that.”
Its search criteria were set to find worlds from 1% the mass of the Moon to 100 times the mass of the Earth, with orbital periods ranging from 20 days to 17 years. days in a row.
The team found that two-thirds of the pulsars in their sample are unlikely to host exoplanets much heavier than Earth, and less than 0.5% likely to host exoplanets in the Poltergeist and Phobetor mass range.
Of the 800 pulsars, 15 showed periodic signals that could be attributed to exoplanets. However, the team believes that most of it can be attributed to the pulsar’s magnetosphere, and one pulsar in particular, PSR J2007+3120, seemed like a promising candidate for pursuing exoplanet surveys.
The team concluded that this means that only 0.5% of pulsars are likely to have Earth-like worlds, which means that the probability of us stumbling across a distant planet with a rare millisecond pulsar for a star is extremely small.
The team also found that pulsar systems are not biased toward any range of exoplanet size or mass, however, any such exoplanets around a pulsar would have highly elliptical orbits, in stark contrast to the semicircular orbits seen in the system. The solar system, and notes that regardless of their shape, the process was different from that which produces planets around young stars that are just beginning their lives.
The team’s research was presented last week at the UK’s National Astronomy Meeting, and published in Monthly Notices of the Royal Astronomical Society.