Radio signals from distant stars suggest hidden planets

With the help of the LOFAR radio telescope, scientists believe they have found hidden planets in the galaxy.

Using the most powerful radio antenna of the world, scientists have discovered stars that suddenly emit radio waves, which could indicate the existence of planets hidden, as published in the journal ‘ Nature Astronomy. ‘

Dr. Benjamin Pope of the University of Queensland in Australia and his colleagues at the Dutch ASTRON National Observatory have been searching for planets using the world’s most powerful radio telescope, the Low-Frequency Array (LOFAR) located in the Netherlands.

“We have discovered signals from 19 distant red dwarf stars, four of which are best explained by the existence of planets orbiting them,” Pope emphasizes. “We have long known that planets in our solar system emit powerful waves of radio by interacting their magnetic fields with the solar wind, but radio signals from planets outside our solar system had not yet been picked up. “

“This discovery is an important step for radio astronomy and could potentially lead to the discovery of planets throughout the galaxy,” he adds.

Previously, astronomers could only detect the closest stars in constant radio emission, and everything else in the radioelectric sky was interstellar gas or exotic like black holes. Now radio astronomers can see simple stars when they make their observations, and with that information, we can search for any planet surrounding those stars.

How was this discovery made?

The team focused on red dwarf stars, much smaller than the Sun and have an intense magnetic activity that drives stellar flares and radio emission. However, some old, magnetically inactive stars were also observed, challenging conventional wisdom.

Dr. Joseph Callingham, from the University of Leiden and ASTRON, and lead author of the discovery, highlights that the team is confident that these signals come from the magnetic connection of stars and planets in orbit that are not seen, similar to the interaction between Jupiter and its moon, Io.

“Our own Earth has auroras, commonly recognized here as northern and southern auroras, which also emit powerful radio waves: this is due to the interaction of the planet’s magnetic field with the solar wind,” he adds. “But in the case of Jupiter’s auroras, they are much stronger, since its volcanic moon Io is expelling material into space, filling Jupiter’s environment with particles that drive unusually powerful auroras.”

Callingham explains that his model for this radio emission from the stars is a scaled version of Jupiter and Io, with a planet enveloped in a star’s magnetic field, feeding material into vast currents that similarly drive bright auroras. “It is a spectacle that has attracted our attention light-years away,” he acknowledges.

The research team now wants to confirm that the proposed planets exist. “We can’t be 100 percent sure that the four stars that we think have planets are hosting planets, but we can say that a planet-star interaction is the best explanation for what we see,” Pope says.

“Follow-up observations have ruled out planets more massive than Earth, but there is nothing to say that a smaller planet would not do this,” he continues.

The discoveries with LOFAR are only the beginning, but the telescope is only capable of surveying relatively close stars, up to 165 light-years away.

With the construction of Australia and South Africa’s Square Kilometer Array radio telescope, expected to turn on in 2029, the team predicts that they will be able to see hundreds of relevant stars at much greater distances.

With information from Europa Press