Scientists Detect Radio Signals From an Exoplanet for the First Time in History

They’re lying. It’s always aliens

Oh shit, Trump is going to be bragging about listening to alien FM radio in about an hour.

So, it was Electronica?

It says “drink your ovaltine”

“Be quiet! They’ll hear you!”

Please don’t decode the signal and make a virus out of it.

How to Serve Man…..is a cookbook

The radio signal apparently translated as, “We’ve been trying to reach you about your car’s extended warranty”

Many planets have naturally occurring magnetic fields which can produce radio signals. Jupiter is a good example. It’s very cool to detect this in other solar systems!

We are all going to become “they”

It’s the alien am radio sports channel. “Borg passes to Borg… passes to Borg… Borg shoots. He scores!”

Astronomer here! I’m third author on this paper and am co-adviser of the PhD student who is first author! TL;DR- Still not aliens, but really fucking cool if you ask me!

So, first up, this has NOT been published yet- we submitted to the journal, and are currently undergoing the peer review process. But the paper prepint was posted to the ArXiv and is getting some press (like from the link), and we are starting to get some press, so I got permission from the lead author to post here!

So, radio emission from exoplanets! As some longtime followers may recall, radio emission is detectable from every planet in our solar system that has a magnetosphere. Most famously, Jupiter is SO radio bright that when its beam of radio emission is pointed at us (caused by particles trapped in its magnetic fields), it’s actually brighter than the sun! So others have tried to spot this sort of radio emission, and there have been some promising cases, but to date nothing definitive has shown up- turns out exoplanets are really far away, and it can be really difficult to distinguish between the star (of which many are also radio bright) and the planet.

One way to get around this is to focus on directly imaged exoplanet systems- that is, systems where we have taken a literal picture of where the exoplanet is compared to the star- because this can then allow you to look with high resolution radio telescopes at the system and pinpoint where the emission is coming from. I actually did this years ago with the VLA, and we detected nothing where we looked. But, funny thing, you of course can’t see the entire sky from the northern hemisphere… and there’s directly imaged systems in the south! And took us awhile to convince the MeerKAT telescope in South Africa, but they finally gave us the time! So we took a look at Beta Pictoris (“Beta Pic”), which is about 63 light years from us.

So, what did we see? In that first test observation, there was a detection from the Beta Pic system! (Fig 1 in the paper.) Ok, let’s get a longer observation… it’s a periodic signal! About 8 hours long, which is as long as the rotation period is for the exoplanet Beta Pic b! (We also noticed the emission was highly polarized, just like what we see from magnetospheres in our solar system, hence the conclusion this isn’t aliens.) The emission is also detected in the 1-3 GHz range- unfortunately MeerKAT can’t go above 3 GHz.

But then, for all my joking of “if this was a northern hemisphere object I would have found it,” the lead author, my student Kevin Ortiz Ceballos, did an AMAZING bit of work to definitively show this emission came from the exoplanet and not the star. (Like, I’m not sure I could have done it- there’s nothing quite like a great student!) He utilized astrometry, which is taking the TINY difference in signal arrival between the antennas, to pinpoint the origin of the radio emission in the system. He then did a bunch of other corrections- from the Gaia satellite, a bright quasar in the field whose position is super well known, and a bunch of other stuff- and finally got a localization you can see here! (Fig 2 in the paper) As you can see- this is DEFINITELY not from the star, but from the location of Beta Pic b!

So what does this tell us? We know because this is a well studied exoplanet that it’s about 10x the mass of Jupiter, and the radio detection allows us to calculate its magnetic field. We end up with a >1200 Gauss magnetic field- for comparison, Jupiter is about 10 Gauss!- and it scales up perfectly from what we see in our solar system! (Figure here) So once again, looks like a magnetosphere, not aliens. 🙂

Next steps are getting through peer review, and hoping MeerKAT gives us our 50+ hours we requested to confirm its periodicity! But I’m really excited that an entirely new exoplanet area is opening up to us! Magnetospheres might not sound exciting at first glance, but they tell us a ton about how these exoplanets formed and even potentially about habitability on them- our own definitely protects life on Earth from harmful solar flares and the like- so I think this is the start of something wonderful.

Also, final note if you’ve read this far- Kevin actually became my student after reading my Reddit post on how to be an astronomer. Per him, he was from a background in Puerto Rico where he wouldn’t have known how to do it, but he just did all the things I said there, and that’s how he got into Harvard grad school for astronomy and that’s how we met. So, that’s awesome- we did it, Reddit!