The Strangest (and Second-Strangest) Star in the Galaxy

By Corey S. Powell | June 30, 2017 11:25 pm
Two ways to look at Tabby's Star: as intriguing data, or as an invitation to flights of fancy. (Credit: Tabetha Boyajian, left;, right)

Two ways to look at Tabby’s Star: as intriguing data, or as an invitation to flights of fancy. (Credit: David Kipping, left;, right)

There’s an old saying: “Great discoveries don’t begin with ‘eureka!’; they begin with ‘that’s funny…’” I’ve long attributed the quote to the renowned science popularizer Isaac Asimov. Jason Wright gently corrects me. He has researched the line, he explains, and could find no evidence that Asimov ever spoke or wrote those words. It was a tidy encapsulation of what Wright is about. He is attracted to the peculiar side of science, and he is also a relentless sleuth.

Wright, an astronomer at Penn State, is one of the lead researchers investigating the decidedly peculiar flickering object commonly known as Tabby’s Star or, in the popular press, as the “alien megastructure star.” The star’s behavior is so puzzling that Wright included among the possible explanations that a huge construction project is orbiting around it. (Note that he never suggested aliens were the best explanation, merely that the hypothesis could not yet be ruled out.) Lately Tabby’s Star has been acting up again, providing intriguing new data but, so far, still no definitive answers.

While Tabby’s Star continues to vex and excite the astronomical community, Wright is busy thinking about other puzzles as well. I was particularly intrigued by another misbehaving star, by the mouthy name of Przybylski’s Star (pronounced “jebilskee,” roughly). If Tabby’s Star is the most mysterious star in our galaxy–an epithet endorsed by Tabetha Boyajian, who first described the star’s irregularities–then Przybylski’s Star may qualify as the second-most strange and mysterious star around. In this case, the puzzle is the star’s composition, which appears to be filled with radioactive actinides, short-lived elements normally found only in nuclear experiments on Earth.

I’m a sucker for unexplained scientific anomalies, so I caught up with Wright to hear his thoughts on these astronomical outliers. What follows is an edited version of our conversation. [For astronomy updates, follow me on Twitter: @coreyspowell]

Tell me about Przybylski’s Star: What is it that makes this object so unusual?

Its spectrum is extremely peculiar. Everyone who’s seen it says it’s the strangest stellar spectrum they’ve ever seen. It’s got an abundance pattern that is very hard to understand. In terms of exactly what abundances of what elements it’s showing us, I don’t know. Some people say there are so many lines you really can’t tell what you’re looking at. [Lines in a star’s spectrum are used to identify its chemical composition.] But, they have to be the lines of some elements! And that’s what people try to figure out.

Some of those elements appear to be short-lived radioactive isotopes, which makes no sense; such atomic nuclei should long ago have decayed and vanished. How can that be?

The identification of short-lived isotopes seems like it must be wrong, because there’s no way to generate them. There is one clever way to hypothesize how they could be generated, however. [The hypothesis is that Przybylski’s Star contains as-yet undiscovered ultraheavy elements, which then decay into the short-lived byproducts we see.] It takes short-lived actinides being in there from being impossible to not totally impossible. The spectroscopic evidence points toward the short-lived nucleotides really being there. Our standard model for stars implies that the observation is probably wrong. But there’s a small possibility that some really cool nuclear physics is going on in this star.

There’s another even further-out possibility, that intelligent aliens put the radioactive elements in there as a kind of chemical signpost…

Carl Sagan and Iosef Shklovskii, along with Frank Drake, had raised the idea of looking for radioactive elements like promethium in stars as a possible alien signal. I found that sort of silly; why would aliens dump their promethium in stars? What would the point be? To get our attention, I guess, but I think there are easier ways to get our attention. It’s neat that somebody said, Hey we should look for it, and then somebody else found something that seems to match what they predicted. But I wouldn’t put alien technology on a serious list of things that might be going on with Przybylski’s Star. [Note: I fixed a transcribing error in the original version of this passage. For more on the Sagan/Shklovskii idea, see Wright’s blog post.]

Jason Wright really enjoys a cracking good astronomical puzzle. (Credit: J. Wright)

Jason Wright really enjoys a cracking good astronomical puzzle. (Credit: J. Wright)

How do you make progress understanding an object that seems to exist in a category of one?

Przybylski’s Star is not entirely alone. It’s the most peculiar of peculiar A stars [white-hot stars, brighter and more massive than our sun]. Other A stars are also peculiar, so it does seem to be part of a family. Like Tabby’s Star, it’s telling us that there are some phenomena out there that we just don’t have a good handle on yet. It means we’re missing something important somewhere, and that’s neat. When you find the anomalies, whatever the answer is it’s interesting.

There are a lot of anomalies that get swept aside with a ‘who cares?’ There’s a triple-star system found by the Kepler space telescope. At least, the pattern of light dips looks a lot like it’s a triple star system of some kind, but no one’s been able to figure out what the three stars are doing. It’s called “the impossible triple.” People just throw their hands up and say, we’re just not clever enough to figure out exactly what we’re seeing. It’s probably just something ordinary we haven’t thought of yet.

The peculiar A stars felt like that to me for a while: curious and but who know why. But if the island of stability [hypothetical ultra-heavy, quasi-stable elements] might be involved, that feels like a high enough reward that it’s worth investigating. Nobody has yet figured out how to generate those elements on Earth. If they are just sitting there in Przybylski’s Star, presumably we could study them there, in a way that’s hard to study them here in the lab. These stars turn out to be a natural laboratory for something really interesting. Or it could all be a mistake!

And what about the more famous mystery star, Tabby’s Star? What’s the latest there?

Telescopes are taking data of the star every day; Tabby [Boyajian] is really in charge of that. Everybody is observing, including AAVSO and the Fairborne Observatory. We just want to catch more of those 10 percent dimming events, and when it happens gather lots and lots of spectra of it as it dips. [Latest updates here.]

We’re looking for spectral changes: When the star is getting dimmer, is that because something is in front of it? If it’s because something’s in front of the star, we want spectra in case it’s absorbing certain wavelengths—that would tell us what it’s made of—and we want to know how much dimmer it is in different wavelengths over time. SWIFT can measure the ultraviolet emission, Las Cumbres and other ground-based observatories can measure optical, Spitzer can measure infrared. Put all that together and we should be able to put a picture together of what we’re looking at!

Everyone wants to know what is making the star flicker. Comets, gas cloud, black hole, aliens. How will we tell?

If diffuse material is passing in front of the star, then it will leave spectral fingerprints [as the light goes through]. We’ll take spectra and look for the usual suspects: hydrogen, sodium, magnesium, the elements that have the strongest fingerprints that we expect to see. If it’s dust, we expect the dips to be deeper in the blue than they are in the red. In blue light or ultraviolet light it will get very dim, and in red or infrared it will hardly get dimmer at all.

If the star gets dimmer the same at all wavelengths, that means we are looking through something very optically thick, meaning that light doesn’t penetrate at any wavelengths. That could be a thick disk with some well-defined edge where we don’t see any diffuse part of it blocking the star. If it’s the star itself getting dimmer, then we’ll expect to see changes in the spectral features of the star as it gets cooler or smaller or whatever it is doing.

What if you don’t see any obvious spectral changes?

Hmmm…I don’t know! If Tabby’s star just gets dimmer but the spectrum doesn’t change, that would be quite a puzzle! You’d have to think of a very dense annulus or something. Right now we’re waiting to see where the data take us. From a SETI perspective, if the spectrum didn’t change but the whole thing got dimmer, that would suggest a large opaque object. But that still wouldn’t prove it.

You drew up a provocative list of potential explanations for Tabby’s star. How do you evaluate what is plausible and implausible when you are dealing with such an unusual object?

We admitted that our list was subjective. You can only do it subjectively. We were trying to stay open minded. One way to do it is to count unicorns. How many unicorns do you have to invoke [to make your explanation work]? There are all those horses out there, and maybe one is a unicorn. Maybe you are allowed one. But once you invoke three of them, your answer becomes so contrived that you look for other explanations. Basically we were counting unicorns. For each explanation, how many crazy things would have to be tricking us?

What draws you to scientific oddballs like Tabby’s Star and Przybylski’s Star?

I like puzzles that not a lot of people are working on. Peculiar A stars were once a hot topic, but there’s a whole younger generation of astronomers who’ve never even heard about them. I thought it was neat to pick it up again and show just how bizarre these things are, and hopefully get some people thinking about it. And indeed, I’ve discovered a few younger astronomers who have recently rediscovered them and are working on them. That’s neat.


  • stargene

    For Tabby’s Star, I was going to suggest a ring of material around the
    star, being perturbed by one or more massive planets. Then I saw the
    wikipedia entry which mentioned Ballesteros’ “Large ringed planet followed by Trojan swarms” hypothesis. Not bad.

    • Corey S Powell

      What makes Tabby’s Star so intriguing is that there are several hypotheses that *almost* match what we are seeing, but so far none of them can explain all of the star’s oddities.

  • Uncle Al

    What could be aperiodically, messily eclipsing Tabby’s star absent a conventional spectral signature? Tangles of spacetime topological defects; gravitationally-bound clouds of magnetic monopoles or dark matter; feh.

    Perhaps the problem is internal. Tabby’s star swallowed a primordial little black hole and it has a perpetual wandering tummy ache.

    • asdfasd

      You don’t swallow a black hole. The black hole swallows you!

      • Uncle Al

        No. A primordial microscopic black hole convecting within Tabby’s star would be stable over time. Megatonnes of matter trying to swirl into a pinprick while being blasted out by potential energy conversion and angular momentum conservation would be a pseudo-equilibrium situation playing aperiodic Hell with the star’s energy output.

        Cf: Thorne–Żytkow objects. Admittedly, one would expect brightening and darkening.

  • Mike Richardson

    Przybylski’s star sounds like something that might happen if a younger star merged with an older white dwarf or neutron star without exceeding the Chandrasekhar limit that would trigger a supernova. Maybe that would generate some of the unusual heavy elements they are detecting.

    As for Tabby’s Star, I’d love for it to be an artificial construct that’s causing the unusual dimming, but the leading theory discussed in the last issue of Sky & Telescope was that it may be a particularly dense localized interstellar dust cloud near the star, and passing between it and our line of sight. That could account for why the dimming appears to be following no predictable pattern, such as what you would expect from an orbiting structure. Though for the record, the astronomers studying the star haven’t completely ruled out aliens!

    • Martin

      Przybylski’s star currently requires a hypothesis of an extra period of the Periodic Table to provide the super-heavy elements that will decay into the actinides observed. We can only make isotopes of these in the lab which last for mere microseconds in some cases, but it is assumed the natural process has an abundance of neutrons for both the Island of Stability elements and their decay products. But none of this has been observed anywhere else in the universe, so it’s a very special kind of supernova. I’m favoring nature here, because lanthanide abundances are also abnormally high, but the relative abundances of each are similar to the Sun, more even-numbered Atomic number than odd.

      Tabby’s star, “constrained dust” seems like an oxymoron. Also, the star is dimming gradually on a timescale of many years besides the transit dips. Few hypotheses explain both.. one of these is aliens.

      • Joshua Golden

        Sounds like I’m supposed to talk to u.. So u know about the magnetic bottles we use here for fusion? Why can’t a star do that? And when they do, wouldn’t they be so much better at fusion that we would see them pulse… He he..

  • 6Doctor6Strangelove6

    Greetings from Arthur C. Clarke and Stanley Kubrick. I want to inform you that Stanley and I conducted a secret experiment using quantum entanglement and telepathy to communicate with an interface. Aliens do indeed exist in another realm now and the Akashic Records. The interface with GOD/ Grand Galactics and aliens is on Facebook. Although, he has not seen the aliens physically, he talks to the ones that have lost their forms in evolution. This experiment was so secret, that even the United States government did not know about it. Stanley insisted on the independence and secrecy of the project. Namely, talking with the dead and/or aliens. It brings me great joy and pleasure to inform you that the experiment was a total success. The interface’s telepathy with us has verifiable proof on Facebook and he is willing to undergo a battery of tests and scrutiny to show his evolution to a higher state of consciousness. No other private or governmental agencies have been successful in talking to formless aliens, Grand Galactics / GOD. Our interface is a Photographer, United States Marine, Artist, Underwater Explorer, Aviation Technician, Lawyer, Humanities major and has direct DNA links to Shamans and Rulers at Gobekli Tepe , Anatolian / Armenian Kings , Biblical Heroes and interestingly for Stanley, he is also related to Napoleon, Jefferson, Franklin and one of the interface’s favorite minds, Tesla. Aliester Crowley/ 666 was also instrumental in the evolutionary development of the telepath’s higher state of consciousness. We are now at the Fifth Seal in Revelations.

    Arthur C. Clarke

    Stanley Kubrick


    • John C

      Sounds like the average Rachel Maddow monologue.

    • SirWilhelm

      You lost me with the Akashic Records. Come back when your writing improves, or you find an editor that understands what you’re trying to say.

    • Joshua Golden

      Carefully who u tell buddy, and how.. U got a start slow.. Find someone on the same page, have a co experience, compair notes.. Ect ect.. Have fun! But a place like this is only going to get u poked at and scorned… So don’t waste ur time confusing these guys.. UV got better thingss to do right! U could be learning about ANYTING IN THE UNIVERSE!!!!! so go! And bring back the best for us! Thanks!

      • 6Doctor6Strangelove6

        Take your own advice JACKASS.

      • 6Doctor6Strangelove6

        Take your own advice.

      • 6Doctor6Strangelove6

        My friends are up in space in low hovering satellites. All you have to do is discern the bull from reality.

  • John C

    “Great discoveries don’t begin with ‘eureka!’; they begin with ‘that’s funny…’”

    Looking forward to the data when it comes in.

    Maybe Tabby’s star will be the pulled thread that opens up a whole new rich area of science.

    • Don Huntington

      “Great discoveries don’t begin with ‘eureka!’; they begin with ‘that’s funny…’”

      Great! It was so good, in fact, that I added it to my collection of quotes: (Send my your last name and I’ll complete the brief citation.)

  • zerobit

    What if aliens didn’t dump their radioactive elements into the star to be discovered. maybe it came from alien satellite probes from distant galaxies that orbited the star or some sort of leftover alien space junk. Could even be from a old civilization that fell into the star.

    At some point in time some alien civilizations probably did the same things human space explorers have done. Left junk floating around.

    • Corey S Powell

      It’s an intriguing idea. There is a whole sub-field of SETI research devoted to looking for relics of alien civilizations that might survive even after they are gone. (The words ‘sub-field’ might give a false impression, however; the entire community of SETI researchers is quite small…but very dedicated!)

      • Razor

        Wish SETI could get ahold of some of the tapes (yes tapes) of unknown sounds at the VLA here in NM. Having dealt with their fire systems we were down there and the guy showing us around to test the various rooms was very chatty and loved showing stuff off. He showed us a whole room of tapes that he claimed all contained signals that “are really cool and bizarre, and a lot we still can’t explain”. But I doubt they will ever see the light of day.

  • 8675310

    I should think that being a scientist from Penn State, the hockey stick university, would, by now, be tainted credentials. Rest assured that if they can figure out a solution that guarantees them an ongoing source of funding, hot damned if this isn’t “settled science.”

  • May Jim

    ”Our standard model for stars implies that the observation is probably
    wrong. But there’s a small possibility that some really cool nuclear
    physics is going on in this star.”


    there is also the possibility that the standard model for stars is wrong! Why is it that the paradigm is never questioned?

    • Joshua Golden

      U got a theory? I’m going with a magnetohydrodynamic acceleration of nucliosynthisis.. And it would also bring them up to the surface..

  • Randy Elble

    I don’t think you will find nucleotides in any star but one that dwells in the sea. You will find nuclides however.

  • Stoic1944

    All this endless talk. Why doesn’t somebody just go there and check it out?

    • SirWilhelm

      You first.

  • jtrollla

    I think God is teasing us.

  • claymore cluepile

    i find astronomy and conundrums like tabby’s star to be the least useful of all the sciences and the most wildly self-indulgent in terms of inventing fabulisms to explain the inexplicable using the untestable. If i was emperor i would divert all the money spent on hubblish telescopes and deep space rockets and give it to the researchers working on doubling the rice harvest and trying to treat cancer.

    • OWilson

      Did you ever consider climate science? :)

      To go to work every day knowing that all the science is settled, and all you have to do is manipulate it to scare the heck (and the money) out of the rubes! :)

      • Scoopjoop

        @OWilson — right, by telling them that climate science is somehow a conspiracy to get more funding. That will get the rubes out to contribute to political campaigns.

        • SirWilhelm

          Isn’t “climate science” just about the money, just as all politics are?

    • Scoopjoop

      Part of what makes us human is wonder and awe at creation. If we don’t care what’s outside of our bubble, if we don’t try to understand the fundamental nature of things, our society and our species—we’re just complicated ants. Making workers and breeding and maximizing the harvest.

      Also, what we live on today and what shapes our world were the untestable conundrums of the early twentieth century. Relativity and quantum mechanics –which were then the purview of daydreaming theoretical physicists –are now the basis for 90% of our technology. Some of which –GPS satellites for example– increase the flipping rice harvest. Dude, how myopic.

  • SirWilhelm

    Even this scientist, Wright, seems unaware of the role electricity plays in the Universe: For instance, evidence has brrn found that fusion takes place in lightning:

    Electricity is scalable. On Earth, it ranges from a spark of static electricity, to lightning. Imagine the power a cosmic scale lightning bolt would have, that extends over many light years? Or, what if stars are really ball lightning, where fusion takes place on the surface of them, and not in their core? Aren’t these things to be considered, instead of rejected out of hand, because conventional science believes electricity is neutral in the Universe, and plays no role in space?

    • Joshua Golden

      U can’t assume they no nothing or ignore it.. Maybe they just don’t follow all the new fusion tech much… Tho that seems hard to imagine.. Hey people have their niches.. I’m sure u do to…

      • SirWilhelm

        Or, maybe they are taught electricity is neutral and plays no role in the Universe, and continue to believe it because it has become dogma for them? Maybe my niche is to question dogma wherever I perceive it?

  • DG

    Man is the only ‘alien’ we know of. Speculation can lead to scientific confirmation, but in itself speculation (e.g., as to alien intelligent life) is not science.

  • JeffCorkern

    Could be a manufacturing facility and we’re seeing the residue. An alien civilization is drawing power from the star to make elements. Given the presence of short-lived isotopes, artificial manufacture is quite likely. Far more likely than Tabby’s Star.

    Makes far more sense to make elements than to mine for them . . .

    • Joshua Golden

      Some elements yes, others idk.. Still its hard to imagn a people so advanced that they can’t use the energy fro those elements..

      • Joshua Golden

        Even if they have like awesme fusion tech, itd b like throwing away all ur batteries just cuz UV got a mostly wireless system.. They can still come in VERY handy..

  • Joshua Golden

    Awesome article. Magnetohydrodynamic modes could support highly focused fusion events ramming enough protons/neutrons in and at the same time also helping to transport the new atoms up to the surface.. The 12 min variation in its luminocity could be a clear indication of a vibrational mode being supported by just such a feed back loop in its core.. How rare is it for stars to have such a composition? I mean close to it.. Like is there a star with just as much or more thorium ect ect.. Thanks!


Out There

Notes from the far edge of space, astronomy, and physics.

About Corey S. Powell

Corey S. Powell is DISCOVER's Editor at Large and former Editor in Chief. Previously he has sat on the board of editors of Scientific American, taught science journalism at NYU, and been fired from NASA. Corey is the author of "20 Ways the World Could End," one of the first doomsday manuals, and "God in the Equation," an examination of the spiritual impulse in modern cosmology. He lives in Brooklyn, under nearly starless skies.


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