(ORDO NEWS) — Astronomers have discovered thousands of exoplanets in recent years. Most of them were discovered by the transit method, when an optical telescope measures the brightness of a star over time.
If the star’s brightness dims slightly, it could mean that a planet has passed in front of it, blocking some of the light. The transit method is a powerful tool, but it has limitations.
One is that a planet must pass between us and its star in order for us to detect it. The transit method relies on optical telescopes. The new method could allow astronomers to detect exoplanets using radio telescopes.
Most planets do not emit as much radio emission as most stars do. Radio light from stars can also be quite variable due to stellar flares.
But large gas planets like Jupiter can be radio bright. The brightness does not come from the planet itself, but from its strong magnetic field.
The charged particles of the stellar wind interact with the magnetic field and emit radio light. Jupiter is so bright in radio emission that it can be detected even with a homemade radio telescope.
But there was no clear radio signal from a planet like Jupiter orbiting another star. In this new study, the group looked at what such a signal might be.
The scientists created their model in magnetohydrodynamics (MHD) and applied it to a planetary system known as HD 189733.
The scientists simulated the interaction of the stellar wind with the planet’s magnetic field, and calculated what the planet’s radio signal would be.
Scientists have found that the planet will produce a distinct curve of light – a radio signal that changes due to the planet’s motion.
This is great news because radio traffic observations are extremely accurate. The researchers also found that radio observations can detect the passage of a planet in front of its star.
There should be specific features in the radio signal showing how the planet’s magnetosphere passes in front of the star.
Both of these signals will be very weak, so a new generation of radio telescopes will be needed to see them.
But if we can detect them, then planetary radio signals will give us an accurate orbital measure of at least one planet in the system and help us understand the exoplanet’s composition. This would be a big leap forward in our understanding of exoplanetary systems.
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