Dr. Benjamin Pope of the University of Queensland and colleagues at ASTRON, the Dutch National Astronomical Observatory, have been using the world’s most powerful radio telescope low-frequency array (LOFAR) in the Netherlands to find planets. “We have found signals from 19 distant red dwarfs, four of which can best be explained by the existence of planets orbiting them,” said Dr. Pope. “We have known for a long time that the planets of our solar system emit powerful radio waves when their magnetic fields interact with the solar wind, but have not yet received radio signals from planets outside the solar system.
“This discovery is an important step in radio astronomy and may lead to the discovery of planets throughout the Milky Way.” In the past, astronomers could only detect the nearest star in a steady radio transmission, and everything else in the radio sky was interstellar gas, or strange gas such as black holes. Now, radio astronomers can see ordinary old stars when making observations. With this information, we can search for any planets around these stars. The team focused on red dwarfs, which are much smaller than the sun and are known to have strong magnetic activity that can drive stellar flares and radio emissions.
But some ancient, magnetically inactive stars have also appeared, challenging traditional understanding. Dr. Joseph Callingham of Leiden University and ASTRON and the lead author of the discovery said that the team believes that these signals come from magnetic connections between stars and invisible orbiting planets, similar to the interaction between Jupiter and its moon Io. “Our own earth has aurora, which is usually considered to be the northern lights and southern aurora, and they also emit powerful radio waves-this is from the interaction of the earth’s magnetic field and the solar wind,” he said.
“But as far as Jupiter’s aurora is concerned, they are much stronger because its volcanic moon Io is ejecting matter into space, filling Jupiter’s environment with particles, driving the extremely powerful aurora. “Our stellar radio emission model is an enlarged version of Jupiter and Io.
A planet is surrounded by the star’s magnetic field, transporting matter into a huge current, and also powering the bright aurora. “This is a spectacle that has attracted our attention from a light-year away.” The research team now wants to confirm that the proposed planet actually exists. “We can’t be 100% sure that the four stars that we think possess planets are indeed planetary hosts, but we can say that planet-star interactions are the best explanation we have seen,” said Dr. Pope. “Subsequent observations ruled out planets that are more massive than the Earth, but there is nothing to say that smaller planets would not do this.
” The discovery of LOFAR is just the beginning, but the telescope can only monitor stars that are closer, up to 165 light-years away.
News Source : Science Daily
