This Planet is Too Hot to Hold Alien Life — But Just Gave Astronomers Hope for It Elsewhere

What that signifies for the hunt for existence is as follows.

Even though the planet in question is not, in and of itself, livable, a recent finding on a rocky little world [this far] away may give some promise in the hunt for viable exoplanets.

A team of scientists headed by Pineda and Vassar College astronomer Jackie Villadsen hypothesize that YZ Ceti b may have a magnetic field that interacts with its star and causes the system to emit radio waves despite orbiting its star at a distance that makes it impossible for it to support liquid water on its surface. The existence of a rocky exoplanet with a magnetic field may also hint at a tiny part of the solution to an urgent habitability conundrum.


Three and possibly a fourth rocky exoplanets, all of which circle their stars too closely to be livable, are illuminated by the faint reddish light of the small star YZ Ceti. The nearest member of the group, YZ Ceti b, travels around the star in just over two days and has surface temperatures that vary from just below the boiling point of water to more than 400 degrees Fahrenheit. It's not the kind of location where you'd typically search for information about life or inhabited worlds.

However, when Pineda and Villadsen used the Karl G. Jansky Very Large Array radio telescope in New Mexico to study the neighborhood star, they discovered recurring radio wave flashes emanating from the system. No, it isn't extraterrestrial life; however, it might be proof that YZ Ceti b has a magnetic field. If Pineda and Villadsen are right—and they say they need more information before they are sure—then at specific places in the planet's trajectory, the magnetic field of the planet reacts with the magnetic field of the star to generate radio waves.

Their results were reported in the journal Nature Astronomy by Pineda and Villadsen.

Despite YZ Ceti b's hot surface, finding a solid, Earth-like world with a powerful magnetic field of one's own would be very exciting for habitability in general. Other stony exoplanets may have magnetic fields if YZ Ceti b does. And if that's the case, then the likelihood of discovering a solid planet with an atmosphere in a red dwarf's habitable zone just rose (even though we don't yet know enough to estimate by how much).


It's most likely going to be somewhere like TRAPPIST-1 or LP-890-9, also known as SPECULOOS-2: rocky, Earth-sized planets circling cool stars referred to as red dwarfs. If we're going to discover life, or even a habitable world, orbiting another star, it's probably going to be there.

One of the main hotspots in the hunt for habitable worlds is TRAPPIST-1. Three rocky exoplanets, out of a total of seven, are present in the region of livable space surrounding the red dwarf star. There is a downside to the star system, however. Some research hypothesized that the red dwarf star may have drained these planets of their atmospheres, leaving them without oxygen and most likely uninhabitable. The habitable zones of red dwarfs are located near by and are known to produce powerful star outbursts.

If so, that wouldn't be good for our odds of discovering extraterrestrial species or even a world that is obviously habitable.

The innermost planet of the TRAPPIST-1 system, TRAPPIST-1 b, was revealed to have no atmosphere, or only a very weak wisp of one, last week, according to a team of scientists. Given how near TRAPPIST-1b is to its star (it is essentially the TRAPPIST-1 version of Mercury, so it gets bombarded with more radiation and stellar wind than its planetary siblings), this shouldn't come as a total surprise, but it's still depressing.

According to NASA scientist Taylor Bell, a co-author of the TRAPPIST-1b study, "I would have been more optimistic for the cooler planets if TRAPPIST-1b had shown clear signs of an atmosphere in our observations."

This summer, JWST scientist Nikole Lewis of Cornell University and her group will direct its potent sensors at TRAPPIST-1e, one of the system's three habitable zone planets.


However, a magnetic field can act as a barrier to prevent charged ions from stealing a planet's atmosphere.

According to NASA astrophysicist Thomas Greene, who wasn't engaged in the YZ Ceti research, "having an organized magnetic field (like Earth's) could make it more likely that a planet could retain its atmosphere." "A field like that could slow or stop charged particles from the star (analogs to our own solar storms)."

Our world is able to support life thanks in large part to the Earth's magnetic field, even at our comparatively close proximity to the Sun. Because of the molten metal in our rotating center, which makes the globe essentially into a gigantic electromagnet, Earth has a pretty powerful magnetic field. Surprisingly, Mercury also has a magnetic field and a liquid center. Venus, on the other hand, lacks magnetic fields as a result of their innards having hardened and cooled over a very long time.

As a result, scientists are unsure of how frequently stony planets can sustain magnetic fields for any length of time, much less long enough to support life. Simply put, we lack sufficient instances.

And that's why YZ Ceti b is so significant. In addition to serving as yet another illustration, it also demonstrates to scientists what to search for in order to discover other rocky planets that might have magnetic fields: radio bursts.

If we can confirm YZ Ceti b's magnetic field and start learning from thousands of exoplanets instead of being limited to a handful of Solar System objects, it would be a big step forward for our understanding of how frequently planets can power and sustain, for billions of years, a strong magnetic field, says Remo Burn of the Max Planck Institute for Astronomy, who was not involved in the YZ Ceti study.

YZ Ceti b produces radio waves when its magnetic field interacts with that of its star, but that interaction is only made feasible by the planet's daringly near orbit. The habitable zones of red dwarf stars like TRAPPIST-1, SPECULOOS-2, and others contain planets that are too far from their stars to produce radio bursts like the ones Pineda and Villadsen observed from YZ Ceti. Planets in these zones include TRAPPIST-1, SPECULOOS-2, and others. In other words, scientists won't be able to use radio bursts to detect worlds with magnetic fields that may be livable. Still, it's beneficial:

We could determine the strength of the magnetic fields on more temperate planets by learning how prevalent magnetic fields are, according to Burn.

Pineda and Villadsen intend to continue watching YZ Ceti in the interim. The possibility that the radio blasts observed with the Very Large Array were not totally powered by the star itself, without assistance from a planet's internal electromagnet, cannot yet be ruled out.

Furthermore, just because a planet, such as YZ Ceti b, has a magnetic field does not mean that it will also have an atmosphere. That relies on the mass of the planet, the density of its atmosphere, the strength of its magnetic field, as well as how frequently and intensely the star flashes.

It's even conceivable that a star like TRAPPIST-1's strong outbursts could heat a planet's core sufficiently to keep it geologically active and generate a shielding magnetic field. Just yet, we don't know. Time and additional evidence will reveal, as always. However, even though it isn't a certainty, it is probable that any habitable planets we discover will have a powerful magnetic field protecting their atmosphere.

"We believe that a balanced environment, neither too heavy nor too light, is essential for existence. But without the safety of a magnetic field, precisely those atmospheres would be lost most effectively," claims Burn. Because of this, it becomes a vital component of existence as we know it.