Colliding magnetic fields reveal unknown planets

Ph.D. candidate astronomer Rob Kavanagh has developed mathematical fashions to raised perceive the interactions between exoplanets and stellar winds and to outline options of exoplanets.

Exoplanets are planets that orbit round different stars than the sun. They’re typically tough to detect, however now it seems that interactions between exoplanets and stellar winds produce indicators that radio telescopes can detect. Stellar winds are scorching streams of charged particles that constantly escape from the surfaces of stars such because the sun.

“When stellar winds collide with the magnetic fields of orbiting planets, the interplay can produce a vibrant emission. On the Earth, we are able to see such emission because the northern lights,” says Kavanagh.

Modeling stellar winds

Final yr, hints of such interactions occurring in different stellar techniques have been detected with the radio telescope LOFAR (Low-Frequency Array) for the primary time. “Round twenty dwarf stars have been discovered that emit radio emission. This might be attributable to exoplanets orbiting round these stars, though they aren’t at present recognized to host any planets,” says Kavanagh. In mathematical fashions he simulates stellar wind environments. That manner, Kavanagh hopes to raised perceive the indicators which can be generated by the interplay between exoplanets and stellar winds.

“Kavanagh’s analysis additionally helps to interpret LOFAR’s new observations,” says his supervisor Aline Vidotto of the Leiden Observatory.

Exploring exoplanets

Kavanagh’s fashions are usually not solely helpful for detecting new exoplanets. Radio emission additionally offers all types of details about, for instance, the scale of the planet and its orbit round its parent star. Kavanagh mentioned, “Wanting on the planets inside our personal solar system, we anticipate that giant planets, orbiting near their guardian star, will produce the strongest radio indicators.”

As well as, the energy of the emission also can reveal one thing in regards to the properties of the stellar winds themselves and the scale of the magnetic area round an exoplanet. “Necessary info, as a result of it’s possible that the Earth’s magnetic area has ensured that we now have an environment,” Kavanagh acknowledged. The presence and measurement of a magnetic field due to this fact offers astronomers with a sign of the habitability of a planet. “And that turns out to be useful within the seek for extraterrestrial life.”

On to ASTRON

Kavanagh is now working as a postdoc at ASTRON, the Netherlands Institute for Radio Astronomy. “Right here I’ll proceed to develop fashions and I will even begin trying into brown dwarf stars. These stars emit an enormous quantity of radio emission, which is puzzling. The extra I give it some thought, the stranger I discover it,” Kavanagh laughs.

In the meantime, Vidotto is completely satisfied that Kavanagh is staying within the Netherlands, trying ahead to future collaborations. “We began our analysis collectively in Eire, however midway via Kavanagh’s Ph.D., I moved to Leiden to make it simpler to collaborate with my colleague-astronomers,” says Vidotto. After some doubt, Kavanagh joined his supervisor. “It was an enormous problem to all of a sudden to migrate in the course of a pandemic, however I am glad I did.”