Scientists suggest that there may be evolutionary parallels on the different worlds because creation tends to be economical. In what could someday lead to a confirmation of that insight, the first radio emission were collected from the magnetic field of a world beyond our solar system by monitoring signals from Constellation Bootes, with the Low Frequency Array (LOFAR) radio telescope in the Netherlands.
From the Tau Boötes Star System
“We present one of the first hints of detecting an exoplanet in the radio realm,” said Jake Turner of the Observatoire de Paris. “The signal is from the Tau Boötes system, which contains a binary star and an exoplanet. We make the case for an emission by the planet itself. From the strength and polarization of the radio signal and the planet’s magnetic field, it is compatible with theoretical predictions.”
Among the co-authors is Turner’s postdoctoral advisor Ray Jayawardhana, a professor of astronomy at Cornell University. The team, led is by Cornell postdoctoral researcher Turner, Philippe Zarka of the Observatoire de Paris – Paris Sciences et Lettres University and Jean-Mathias Griessmeier of the Université d’Orléans.
“If confirmed through follow-up observations,” Jayawardhana said, “this radio detection opens up a new window on exoplanets, giving us a novel way to examine alien worlds that are tens of light-years away.”
“A Significant Radio Signature”
Using LOFAR, Turner and his colleagues uncovered emission bursts from a star-system hosting a so-called hot Jupiter, a gaseous giant planet that is very close to its own sun. The group also observed other potential exoplanetary radio-emission candidates in the 55 Cancri (in the constellation Cancer) and Upsilon Andromedae systems. Only the Tau Boötes exoplanet system – about 51 light-years away – exhibited a significant radio signature, a unique potential window on the planet’s magnetic field.
Observing an exoplanet’s magnetic field helps astronomers decipher a planet’s interior and atmospheric properties, as well as the physics of star-planet interactions, said Turner, a member of Cornell’s Carl Sagan Institute.
Magnetic Field Hints at Possible Habitability
“The magnetic field of Earth-like exoplanets may contribute to their possible habitability,” Turner said, “by shielding their own atmospheres from solar wind and cosmic rays, and protecting the planet from atmospheric loss.” Realizing, of course, that habitability does not equal life.
Two years ago, Turner and his colleagues examined the radio emission signature of Jupiter and scaled those emissions to mimic the possible signatures from a distant Jupiter-like exoplanet. Those results became the template for searching radio emission from exoplanets 40 to 100 light-years away.
After poring over nearly 100-hours of radio observations, the researchers were able to find the expected hot Jupiter signature in Tau Boötes. “We learned from our own Jupiter what this kind of detection looks like. We went searching for it and we found it,” Turner said. “There remains some uncertainty that the detected radio signal is from the planet. The need for follow-up observations is critical.”
Turner and his team have begun a campaign using multiple radio telescopes to follow up on the Tau Boötes signal.
The Daily Galaxy, curated and edited by Sam Cabot, via Cornell University
Image credit: top of page, radio source 3C 75 in the cluster of galaxies Abell 400 taken with the Very Large Array (VLA) at Socorro, New Mexico, at a wavelength of 20 cm (8 inches). Red shows regions of intense radio emission, while blue shows regions of fainter emission. The image consists of two twin jet radio sources. The jets bend and appear to be interacting. NRAO/AUI and F.N. Owen, C.P. O’Dea, M. Inoue, & J. Eilek