Scientists suggest distant object may have an atmosphere
Astronomers have detected a repeating radio signal from an exoplanet and the star it orbits, located 12 light-years from Earth. The signal suggests that an Earth-sized planet might have a magnetic field and possibly even an atmosphere.
Earth's magnetic field protects the planet's atmosphere, essential for life to survive, by deflecting energy particles and plasma that emanate from the sun. Detection of atmospheres around planets located outside our solar system could point to other worlds that could potentially support life, says CNN.
Scientists noticed strong radio waves from the star YZ Ceti and a rocky exoplanet orbiting it, called YZ Ceti b, while observing with the Carl G. Jansky Very Large Array of Telescopes in New Mexico. The researchers believe the radio signal was created by an interaction between the planet's magnetic field and the star.
The study, detailing the results, was published Monday in the journal Nature Astronomy.
“We saw the initial surge and it looked beautiful, – study lead author Sebastian Pineda, a research astrophysicist at the University of Colorado Boulder, said in a statement. – When we saw it again, it was very revealing that, ok'maybe we really have something here”.
According to Pineda, magnetic fields can prevent shrinkage and significant destruction planet's atmosphere over time as particles are released from the star and bombard it.
For radio waves to be detectable on Earth, they must be very strong, the researchers say.
“Whether a planet survives with or without an atmosphere may depend on whether the planet has a strong magnetic field or no”,– says Sebastian Pineda.
Previously, researchers have detected magnetic fields on exoplanets similar in size to Jupiter, the largest planet in our solar system. But finding magnetic fields on planets smaller than Earth is more difficult because magnetic fields are virtually invisible.
“What we do, – it's looking for a way to see them”, – study co-author Jackie Villadsen, assistant professor of physics and astronomy at Bucknell University in Pennsylvania, said in a statement.
“We are looking for planets that are really close to their stars and similar in size to the Earth, – she said. – These planets are too close to their stars to be a place where you could live, but because they are so close, the planet sort of pushes through a bunch of stuff coming from the star. If a planet has a magnetic field and passes through enough stellar matter, it will cause the star to emit bright radio waves”.
As CNN notes, the planet YZ Ceti b takes only two Earth days to complete one revolution around its star. Meanwhile, the shortest orbit in our solar system is the planet Mercury, which takes 88 Earth days to make a complete revolution around the Sun.
While the exoplanet YZ Ceti b orbits its star, the star's plasma collides with the planet's magnetic field, bounces off and interacts with the star's magnetic field. All of these energy reactions create and emit strong radio waves that can be detected on Earth.
The researchers measured the radio waves they detected to determine the strength of the planet's magnetic field.
“This gives us new information about the environment around the stars,– Sebastian Pineda says – This idea – what we call «extrasolar space weather».
In our solar system, solar activity can create space weather that affects the Earth. Energy bursts from the sun can disrupt satellites and global telecommunications and cause dazzling light shows near the Earth's poles, such as the northern lights.
Scientists speculate that the interaction between YZ Ceti and its planet also creates an aurora, but this light show is actually happening on a star.
“We do see an aurora on the star – that's what this radio emission is, – Pineda said. – The planet should also have an aurora if it has its own atmosphere”.
Researchers believe that YZ Ceti b – the best candidate for a rocky exoplanet with a magnetic field discovered so far.
“That may indeed be true, – Willadsen notes. – But I think it will take a lot of follow-up work before there is really conclusive confirmation of the radio waves caused by the planet”.
New radio telescopes that are about to be commissioned this decade could help astronomers more often, researchers say. detect signals indicative of magnetic fields.
“The search for potentially habitable worlds in other solar systems depends in part on being able to determine whether rocky Earth-like exoplanets actually have magnetic fields, – comments Joe Pesce, program director at the National Radio Astronomy Observatory, in a statement. – This study shows that not only is this particular rocky exoplanet likely to have a magnetic field, but also provides a promising method for finding more”.