The discovery of the first exoplanets was a “stroke of luck”, according to a study

A new study, led by the University of Manchester in the UK, says that the historical discovery of the first three exoplanets in the early 1990s was a stroke of luck and could not have happened easily.

Exoplanets, as you may already know, are planets outside our solar system. Today we have 5,108 verified from almost 3,800 systems. But just over 30 years ago, the idea of ​​planets outside our region was invented only in the best science fiction productions.

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Illustration of the Pulsar planetary system lichwith exoplanets fighting spirit, Fobetor and Ghost: the three were discovered by chance, according to a new study (Image: Pablo Carlos Budassi / NASA / Reproduction)

To refresh your memory (or tell you who is too young to remember), astronomers Alexander Wolszczan and Dale Frail recorded in January 1992 the first two exoplanets in history, with the third coming in 1994. All three are 4, respectively. 3, 3.9 and 0.2 times the mass of the Earth and all are rocky in nature, just like our home.

All three revolve around a rare type of dead star called a “millisecond pulsar” called “B1257 + 12″ or, if you are more intimate, ” lich”, Name given to a powerful and immortal being from various folklore.

And here, in exoplanet research, is where “happiness” comes in: according to the Manchester study, ordinary pulsars are already incredibly rare – 3,320 known in the Milky Way. Of these, only half a percent (0.5%) “probably” have rocky planets orbiting them. In expressed numbers: out of 3,320 known pulsars, only 16 can have rocky exoplanets near them.

Pulsars are essentially neutron stars that spin so fast that they emit rays of radiation from their poles. These rays pass close to the Earth and give those who observe them from here the impression that they are “pulsating” – hence their name. Among these are pulsars at such a high speed that their rotations are literally milliseconds – and the pulses that refer to these rotations have the same duration.

Pulsars with exoplanets around them are not necessarily impossible, but for the most part these planets are huge (or small and strange, like an ultra-dense object, which some believe is the remnants of a white dwarf star that the pulsar came to “eat” up “) .

With this in mind, the team led by Iuliana Nitu tried to establish an index of the vulgarity of the planets under these conditions. “Exactly 30 years ago, the first exoplanets were discovered around a pulsar, but we still do not understand how these planets can form and survive under such extreme conditions. “Finding out how common they are and what they look like is a crucial step in that direction,” she said.

By setting parameters to search for planets with a minimum of 1% of the Moon’s mass and a maximum of 100 times the Earth’s mass, with orbital periods between 20 days and 17 years, the team determined that it would be enough to discover two original exoplanets around Lich Earth – resp. fighting spirit and Fobetor.

In response, the team concluded that two-thirds of the pulsars in this sample would probably not have exoplanets much heavier than Earth, and less than 0.5% of them would not have the average mass of Poltergeist and Phobetor. At the same time, planets suffer Ghost (the third discovered exoplanet) would not be found 95% of the time.

To put it bluntly: out of 800 pulsars, only 15 showed pulse signals attributable to exoplanets in their regions. However, the team believes that the number may be even lower, as much of these 15 may still be an ‘echo’ from the magnetosphere of the pulse itself (ie ‘noise’ from pulses, jamming of the signal).

In this finding, only one pulsar was found to be a viable candidate for exoplanet studies: PSR J2007 + 3120.

That is, only half a percent of known pulsars should be able to exhibit Earth-like planets, making the probability of finding such objects quite low. In addition, pulsar systems are not dependent on the mass of any exoplanet, and any exoplanet around a pulsar would have an elliptical orbit, not a perfect circumference.

In other words: no matter how these specific systems were formed, the process was completely different from what we know of an ordinary star – like our solar system.

The entire study has been published in Royal Astronomical Society monthly announcements.

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