ASTRONOMERS DETECT RADIO SIGNALS FROM EXOPLANET FOR FIRST TIME

Astronomers have detected radio signals coming directly from an exoplanet for the first time, according to a paper on the arXiv preprint server. A team led by Kevin Ortiz Ceballos at the Centre for Astrophysics, Harvard & Smithsonian, traced the signal to β Pictoris b, a gas giant orbiting a star around 64 light-years from Earth. The researchers said the signals come from auroras linked to the planet's magnetic field, not from any form of communication. Auroras form when charged particles travel along magnetic field lines and interact with a planet's atmosphere, as with the northern lights on Earth.

The team used South Africa's MeerKAT radio telescope to observe the β Pictoris system, picking up faint, repeating radio bursts. They initially could not tell whether the signals came from the star or the planet, so they compared their radio images with the precise positions of distant background quasars, used as fixed reference points. This let them map the exact locations of both the star and the planet. When the images were overlaid on that map, the signal matched the position of β Pictoris b rather than its star, the researchers said.

The detection also allowed the team to measure the planet's magnetic field, calculated at a minimum of 1,250 gauss where the radio waves are produced, according to the paper. They said this is far stronger than Jupiter's magnetic field. The authors described the work as the first direct detection of auroral radio emission from an exoplanet, using the MeerKAT array. Astronomers have studied exoplanets since the first were discovered in the 1990s, and researchers said the technique could help reveal more about magnetic fields on other distant worlds.