Scientists have found a new way to detect alien worlds in the universe

Deepak Gupta August 18, 2022
Updated 2022/08/18 at 4:18 PM

With powerful telescopes, we have been able to discover thousands of exoplanets in recent years. Most of these worlds were found via the transit method, where an optical telescope measures a star’s brightness over time. If the star dips very slightly in brightness, it could indicate that a planet has passed in front of it, blocking some of the light.

The transit method is limited and can now be replaced by the use of radio telescopes.

Alien worlds now under the eye of radio telescopes

The transit method is a powerful tool, but it has limitations. One of which is that the planet has to pass between us and its star for us to detect it. The transit method is also based on optical telescopes.

But a new method could allow astronomers to detect exoplanets using radio telescopes.

It is not easy to observe exoplanets at radio wavelengths. Most planets don't emit much radio light, and most stars do. Radio light from stars can also be quite variable due to things such as stellar flares.

However, large gas planets such as Jupiter can emit radio light. Not from the planet itself, but from its strong magnetic field. The stellar wind's charged particles interact with the magnetic field and emit radio light.

Jupiter is so bright in radio light that it can be detected with a homemade radio telescopeand astronomers detected radio signals from several brown dwarfs.

But there is no clear radio signal from a Jupiter-like planet orbiting another star.

Method uses magnetohydrodynamics

In this new study, the team wondered how it might achieve that. The team based its model on magnetohydrodynamics (MHD), which describes how magnetic fields and ionized gases interact, and applied it to a planetary system known as HD 189733which is known to have a Jupiter-sized world.

They simulated how the star's stellar wind interacted with the planet's magnetic field and calculated what the planet's radio signal would be. In this exercise they managed to find several interesting results.

For one, the team showed that the planet would produce a clear light curve. It is a radio signal that varies because of the movement of the planet.

This is great because observations of radio motion are extremely accurate. Even more accurate than optical Doppler observations.

They also found that radio observations could detect a transit of a planet passing in front of its star. There would be specific features in the radio signal showing how the planet's magnetosphere passes in front of the star. Thus, astronomers could better understand the strength and size of the planet's magnetosphere.

Both of these signals would be very weak, so a new generation of radio telescopes would be needed to see them.

According to the researchers, if we can detect them, planetary radio signals will give us an accurate orbital measurement of at least one planet in the system and help us understand the composition and interior of an exoplanet.

Together, these would be a huge leap forward in our understanding of exoplanetary systems.

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