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Researchers from Tel Aviv University discovered the first planet found together with a brown dwarf

An unusual planet outside the solar system has been discovered

Avi Blizovsky

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Dr. Shai Zucker and Prof. Zvi Maza from Tel Aviv University, in collaboration with a Swiss team, recently discovered an unusual planet outside the solar system. The planet was discovered as part of a study that includes observations by the Swiss team in telescopes in France and Chile, and data analysis performed by the Israeli team. One of the stars examined in the research is the star HD41004. A preliminary analysis of the light coming from the star apparently indicated the existence of a planet that orbited the star at a very fast rate of once every 30 hours. Such an orbit seems suspicious because to date the existence of a planet with such a fast cycle has not been confirmed. Analysis using an innovative method developed by Israeli researchers made it possible to identify that it is actually two stars (suns). The smaller sun is surrounded by an object called a "brown dwarf" - a small star-like object, larger than a normal planet, and it is the one that makes the orbit every 30 hours. The continuation of the observations and the analysis showed that, after all, there is also a planet in the system, which orbits the larger sun, and completes one orbit every 600 days or so.

Planets outside the solar system were first discovered only about ten years ago, despite intensive efforts over centuries. Today, about a hundred such planets are known, but the one found in the HD41004 system is the first to be found together with a brown dwarf. Brown dwarfs are also rare "creatures" that are very difficult to discover. The system HD41004 is the first system of its kind, which has both a double star, a brown dwarf and a planet, in a unique arrangement. The fact that such a special system was found shows, perhaps, that the formation processes of binary stars, planets and brown dwarfs are more closely related than scientists first assumed. A study of systems of this type may shed light on the way in which systems of planets such as our solar system form and develop, on the conditions for their stability and their frequency in the universe. Its discovery was only possible thanks to the combination of the advanced equipment developed by the Swiss team and the surgical method developed by the Israeli team. The Swiss team is headed by Prof. Michel Muir, director of the University of Geneva Observatory, who was among the candidates for this year's Dan-David Prize.

From an astrophysical point of view, the system is the first of its kind - not many systems of four objects are known, and certainly not systems with stars, a brown dwarf and a planet. When it comes to more than two objects, the mutual influence between them can lead to the disintegration of the system, and the question arises whether conditions exist in the system that contribute to its stability. Also, it is clear that the creation processes of a double star, a brown dwarf and a planet took place in this system, and it is a "laboratory" for examining the interaction between these processes. Technically, the light that came from both stars (the brown dwarf and the planet hardly shine), comes together. Until the development of the method in Tel Aviv there was no reliable way to reach such a discovery. The developed method makes it possible to separate the light into the two components and measure their speed separately, even though the light that reaches the earth is "mixed".

Note regarding NASA's discovery from today (publication in Haaretz newspaper, Yuval Dror) - the discovery of the absence of direct consequences on the subject of life in space

The planet discovered around the pair of the pulsar and the white dwarf is indeed an important discovery, both because it is the first time a planet has been discovered around a pair of objects and also because of the issue of the age of the system. The system is in a "star cluster" - a large and very dense group of stars. According to the proposed scenario, the planet first orbited one sun, which later turned into a white dwarf and was then "captured" by a "neutron star" (the pulsar). However, there are still many question marks here, for example, are the processes of planet formation within a star cluster similar to ours (and there are reasons to assume that they are not)?

Also, when we talk about planets outside the solar system, we usually talk about planets orbiting ordinary stars ("suns"), which naturally interest us when it comes to the existence of life. In this discovery, it is a planet that was created at a very early stage of the universe, when the necessary elements for life were not yet present (they are created only at a later stage), therefore, there are no direct implications here for the subject of life in space
Know planets outside the solar system

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