How a crowd-favorite planet became the hellish world it is today

Only about 41 light-years from Earth, our planet has a hell of a cousin. It’s a strange world called 55 Cnc e, aka Janssen, which tests the limits of how close a planet can get to its host star before exploding; evaporating; melting. Janssen orbits its star close enough that if you were to travel there, a full year would last only 18 hours. It has a surface that is literally an ocean of lava.

And, as if that weren’t character enough, this orb doesn’t even revolve around its star in a flat trajectory.

In our solar system, of course, the planets orbit the sun in a uniform path like the rings around Saturn: a pancake of little kingdoms, though ex-planet Pluto technically does its thing. But Jansen? No. This globe is completely a planet and completely misaligned. For some reason, it mysteriously traverses an alternate plane and even shields itself from our telescopes.

So, unsurprisingly, this super-Earth (it can fit about eight Earths inside) caught the attention of astronomers around the world.

“55 Cnc e is a very interesting target and I dare say a crowd favourite!” said Lily Zhao, a researcher at the Flatiron Institute’s Center for Computational Astrophysics in New York City.

One of many concentrating on this orb, Zhao and his fellow researchers published a paper Thursday in the journal Nature Astronomy that appears to answer an obvious question about Janssen. We know it’s surprisingly hot and just plain weird, yeah, but What Did it become the scorching and strange place that it appears to be today?

Armed with a tool called the Extreme Precision Spectrometer, or EXPRESS, they discovered that the burning world likely formed in a relatively cooler orbit a long time ago (which was still extremely warm, to be clear) but was progressively pushed towards its star, called Copernicus. due to gravitational eddies created by the other four planets in the system.

Eventually, Janssen made it to the place he is now, sweltering next to beams of radiant stars and under humanity’s microscope.

An informative diagram showing how 55 Cnc e follows a strange orbit around its sun, Copernicus.

L. Zhao et al./Nature Astronomy 2022

Previously, scientists had suggested that the gravity of a nearby red dwarf star, rather than the adjacent planets themselves, was to blame for Janssen’s relocation. However, Zhao explained, “because we found that 55 Cnc e has an orbit aligned with the star’s equator, this favors more dynamically smooth forms of migration.”

Little nudges from the family, you could say.

Thanks to EXPRESS, this marks the smallest measurement of its kind to date. This means that, in the future, the promise of the machine could be limitless.

“EXPRES is part of a generation of instruments designed to be more precise and therefore sensitive to smaller signals, such as those from habitable or even Earth-like planets,” Zhao said. “We are now able to detect signals of the magnitude necessary to find Earths in other parts of the universe, planets that would be hospitable to life.

“Now it’s just a matter of getting enough data to find them!”

A strange place for planets.

When I first heard that the Copernican star system has planets following mismatched paths, I’ll be honest, I envisioned a bunch of worlds orbiting a star like the electrons in Jimmy Neutron’s atomic shirt revolving around a nucleus of protons. and neutrons.

The good news here is that maybe he was right.

An image of an atomic structure shows green electrons orbiting blue and red protons and neutrons in a variety of planes.

This is not an anatomically accurate image of an atom. But it’s what I assumed Copernicus would look like, in my wild imagination. The green bits are “electrons” and the blue and red bits are protons and neutrons in the “nucleus”. Also, Jimmy Neutron’s t-shirt has a picture like this on it.

fake images

Although scientists know that Janssen’s four brothers are also not aligned with Copernicus (ground-based telescopes don’t see them crossing between our planet and the star, even though Janssen does), we haven’t measured their trajectories accurately enough to figure out how they move.

“Since 55 Cnc e is the only transiting planet, it is the only planet for which measurements like this are possible,” Zhao said. “With astrometric data, we could learn the orientation of the other planets relative to 55 Cnc e and use this measurement to anchor the orbital alignments of the other planets, but the ability to make such a measurement has not yet been demonstrated.”

The bad news, however, is that he probably wasn’t right.

“From the information we have obtained, I think it is unlikely that the other planets are extremely varied,” Zhao said, referring to how EXPRESS discovered that Janssen was more closely aligned with its star’s equator. “A highly varied system would likely be the result of some chaotic process that would not result in 55 Cnc e being as well aligned.”

Other angles of physics also seem to be incorrectly proving my fantastic theory of the atom, such as the fact that in order for planets not to transit between Earth and their star, they Really it has to be very misaligned. They could be a bit off-road.

“Because they orbit well beyond 55 Cnc e, they actually only have to get slightly misaligned so they don’t pass between us and the star anymore, so there’s not a strong constraint on the other planet’s orbits that way either.” Zhao said. .

Also, in general, star systems tend to form more aligned like ours and mix over time, if at all. That’s because planets usually arise from what’s known as a protoplanetary disk of random bits of gas, dust, rock—whatever, really—that eventually condense into floating spheres.

But gravity has a mind of its own, pushing and pulling things until it finds a balance you like, even though that balance may or may not be very different from the starting point of the system.

An illustration of the planetary trajectories of our solar system.  They are all in line except Pluto, but of course Pluto is no longer a planet.  Sad.

An illustration of the alignments of the planets in our solar system. You can also check out Pluto’s weird antics here. The Line of Nodes is the intersection between the orbital plane of Pluto (purple) and that of Earth (white). It occurs at intervals of 87 and 161 years.

Ana Verbiscer/NASA

Fortunately, according to Zhao, the solar system seems to already have that special balance, and therefore probably won’t push Mars into the skies and bury Earth in the basement.

Nonetheless, it’s incredibly intriguing to see an unstable solar system unlike our own, highlighting just how different every corner of the universe must be, and how quickly they can evolve. and now that we can detect them, it’s much more interesting.

“It’s exciting to now have this measurement in hand that shows that the instrument we built is working and is delivering the kind of results we built it for,” Zhao said.

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