US, WASHINGTON (NEWS OBSERVATORY) — The new method allows you to find rocky planets like Mercury, Venus, Earth and Mars. Astronomers have discovered an exoplanet the size of the Earth in the orbit of the star GJ 1151, which is located just 26 light years from the Sun. The basis of the new method, scientists took the interaction between the magnetic field of Jupiter and its moon.
“We have adapted the knowledge from decades of radio observations of Jupiter to the case of this star. It has long been predicted that a large-scale version of the interaction of Jupiter with Io exists in systems between stars and planets, and the radiation we observe corresponds very well with this theory,” said Joe Culling, co-author of a study from the Netherlands Institute of Radio Astronomy (ASTRON).
To date, there have been two main ways to detect exoplanets. The transit method helps to find the planet when it passes between its star and the Earth – this is reflected in the luminosity of the star and reveals to us the location of the object of study. The Doppler method or the radial velocity method consists in spectrometric measurement of the radial velocity of a star with a planetary system.
The interaction between Jupiter and Io is interesting because the gas giant produces signature radiation on radio waves, which are mainly polarized in a circle and which can be more powerful at lower frequencies than similar wavelengths from the Sun.
The magnetic field of the sun is not strong enough, and the distances are too large to produce a similar effect from its interaction with the planets of the solar system. But red dwarfs have much more powerful magnetic fields that can be detected.
Astronomer Harish Vedantam from ASTRON and an international team of researchers decided to look for low-frequency circularly polarized radio waves. They used data from a study using the LOFAR telescope in the Netherlands, which scans the sky at low radio frequencies. Scientists have identified several emissions that correspond to red dwarfs.
One of these stars was GJ 1151. It turned out to be an ideal candidate for further study. Many red dwarfs – especially those found on radio waves – are extremely turbulent. They fill the space around them with stellar flashes, spinning very fast or interacting with a satellite star. GJ 1151 rotates extremely slowly, making only one revolution in 130 Earth days. In addition, scientists ruled out the presence of a companion star near it.
“… we were looking for evidence that a companion star masquerades as an exoplanet in radio data. But we ruled out this scenario and believe that GJ 1151 has a Earth-sized planet that is too small to be detected by our optical instruments,” said Benjamin Pope, co-author of the study from New York University.
The exact mass of this planet has yet to be determined, but scientists suggest that it is a rocky body that makes a revolution around its star every 1-5 days. It is quite close to a star and probably cannot be potentially inhabited.
Scientists note that the transit method and the Doppler method allow us to detect mainly large planets, like Jupiter, Saturn, Neptune and Uranus. The new method, by contrast, is promising from the point of view of detecting less massive exoplanets.
“The long-term goal is to determine how the magnetic activity of a star affects the habitability of an exoplanet, and radio emission is a big part of this puzzle. Our work has shown that it is viable with the new generation of radio telescopes and set us on a fascinating path,” concludes Vedanta.
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