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Space Science

Second Irregularly Dimming Star Found (phys.org) 151

Posted by EditorDavid from the star-search dept.
Long-time Slashdot reader RockDoctor writes: Remember the screaming and welcoming of our Dyson-Sphere-Dwelling 1500 LY distant Overlords that accompanied the news that star KIC 8462852 was irregularly dimming on both short and longer timescales? A second star with a similar light curve has been discovered and reported on ARXIV.

With the euphonious names "EPIC 204278916" and "2MASS J16020757-2257467", the star is a young M1 (red) star, traveling as part of a group of stars which haven't had time to disperse from their place of formation. The age is estimated at 5 — 11 million years. Analysis of 70+ days of data from the K2 mission epoch shows a rotation of 3.6 days, but a period of 25 days near the start of the observation epoch showed dips in intensity of up to 60% lasting for up to about a day each. Details are in the Arxiv paper linked to above, particularly figures 1 and 4.

If confirmed, this discovery changes the situation with interpreting the so-called "Tabby's Star". Firstly with a second object in the class, the odds of it representing a class of naturally occurring objects compared to a unique, unusual object is greatly increased. Secondly, the different celestial mechanical situations around the different stars allows a better estimate of plausible formation mechanisms. One potentially important point is that clumps of debris that could produce these dimmings seem to be quite large. "It is also important to note that the resulting size for the transiting and occulting clump would be quite large at with the clump being in the order of 1.5 times the radius of the Sun. Sadly, this appears to be a new class of "dirty young planetary system." no alien Overlords, no screaming in the streets. Just business-like astronomy.
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Second Irregularly Dimming Star Found More

Second Irregularly Dimming Star Found

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  • Dyson-Sphere-Dwelling (Score:3)

    by hcs_$reboot ( 1536101 ) on Saturday September 03, 2016 @08:44PM (#52823041)
    It's a Dyson. It shines in a shop window. It dims when you start using it.
    • Since Mr Dyson is a competent engineer, I would be pretty surprised if he didn't know of the "classic" Dyson Sphere. Whether the Marketing Department (to each, their own skills) has canned the idea of using the name as "too geeky", or whether they're keeping the name in the "pool" but haven't found the right product to put it to yet, I don't know. And I doubt that we'd get an answer if asked.

      OTOH, I'll file the question in case I ever see Dyson doing a Q&A session here.

  • If you are an advanced alien race that needs more living space, it's much more practical to construct a partial dyson sphere in your own back yard, than to colonize other star systems. Our galaxy is big enough that there should be multiple inhabited star systems out there, and possibly multiple partial dyson spheres. But the laws of physics make visits from flesh and blood aliens highly unlikely.

    • Re:of course, no alien overlords (Score:4, Funny)

      by CanadianMacFan ( 1900244 ) on Saturday September 03, 2016 @10:07PM (#52823241)

      No other civilization is going to use a Dyson sphere. Their products are so user unfriendly. I bought one of their fans and had to return it because it was so badly thought out. There's no way that company could design a sphere to enclose a sun properly.

    • But the laws of physics make visits from flesh and blood aliens highly unlikely.

      I suspect becoming a truly spacefaring species means the ability to alter your flesh and blood to forms more suitable to space and alien environments at will, for example through mind uploading. There are potential additional benefits as well, such as intelligence boost or true multitasking.

    • If you are an advanced alien race that needs more living space, it's much more practical to construct a partial dyson sphere in your own back yard,

      I really doubt it. If you're an advanced race (hoomin, alien, or our current feline overlords) living within the laws of physics, then the need for living space can be much more easily accommodated by turning asteroids into large numbers of hollow, spin-stabilised structures. It's much simpler, incredibly more fault tolerant, and doesn't require the disassembly a

  • "
    If confirmed, this discovery changes the situation with interpreting the so-called "Tabby's Star"."

    The most important reason why this deprecates Tabby's Star as an alien megastructure is that at 5-11 million years, this new star is far too young to have undergone planet formation, let alone a highly developed civilization. If we can identify a natural mechanism for its odd light changes, Occam says this is the most likely explanation for Tabby's Star also.

    Meanwhile, we ourselves are making these observatio

    • We have known for quite some time that young stars can behave this way. The reason Tabby is odd is because it DOESN’T appear to be young. I doubt the same mechanism will explain both unless Tabby’s age is radically down graded. I suppose that could happen, but the reason I believe it won’t is the highly symmetric first dip and the another dip indicating a huge ring structure object, then came the wacky random fluctuations that without the other two anomalies would like a young planetary

    • The most important reason why this deprecates Tabby's Star as an alien megastructure is that at 5-11 million years, this new star is far too young to have undergone planet formation, let alone a highly developed civilization.

      The civilization that build the megastructure may have evolved elsewhere and then migrated to this star. The lack of planet formation is an advantage since the first step in building a dyson sphere is to ... disassemble the planets. It would be much easier to start with a cloud of comets and asteroids. That may have been one reason they chose this star for their project.

      • Re: (Score:2)

        by Zocalo ( 252965 )
        While I do think this is just some new natural phenomenon, just to play devil's advocate for a minute, which of these is likely to be the simplest and provide the longest return on investment for a suitably advanced civilization to construct a Dyson sphere from, assuming (as would be likely) that interstellar travel isn't a significant problem:

        A: A mature star system, where most of the raw materials for construction have already coalesced into planets, and may only have 2/3 of its stellar life left.
        B: A
        • Comment removed based on user account deletion

          • Some other factors:
            1) You haven't exactly built thousands of Dyson Spheres, so each one is still a big project and a big risk. Better to do it on some young star without any inhabited planets.
            2) Maybe a small, young star represents a lower engineering challenge than a larger star, much like a space elevator is a huge engineering challenge to us on Earth because of the necessary material strength, whereas building one on the Moon would be far, far easier and well within our materials technology.

        • A: A mature star system, where most of the raw materials for construction have already coalesced into planets, and may only have 2/3 of its stellar life left.
          B: A new star system, where most of the raw materials for construction are still drifting around in the form of large rocks and the star has its entire life left.
          Pretty sure it's "B" -

          In your "B" scenario, don't forget that you've got a LOT of volatiles still floating around, unless you've already built your gas giants. In which case, you're into scena

          • Re: (Score:2)

            by Zocalo ( 252965 )
            Yeah, it would be all in the timing. You'd definitely want the first stages of planetary accretion completed in order to to get most of the initial gas and dust into a form that can be turned into asteroid sized building blocks, yet avoid things reaching the point where you have proto-planets that are binding up most of your heavy metals in a mostly molten state. I suppose that you *could* get in earlier than that if your construction tools and processes were to include a "Space Balls" style cosmic vacuum
            • Given the comparative difficulty of turning asteroids into living space versus building a Dyson object {sphere, ring, cup, mesh ... whatever), I honestly cannot see how any space-faring species woud waste effort on building a Dyson [whatever]. Until they have literally run out of places to live in their entire galaxy, it's a non-starter. IMHO.

              • Maybe they've already built asteroid-habitats and are bored of that, and want to build something much bigger and fancier. After all, if they've figured out how to eliminate aging and have virtually unlimited lifespans, maybe they have little better to do than come up with fantastic new construction projects. And with no significant death rate, maybe they're having fun breeding as many new baby aliens as they can so they need lots of space for them.

      • The civilization that build the megastructure may have evolved elsewhere and then migrated to this star.

        When SF authors make this sort of suggestion, they normally have some sort of hand-wavey McGuffin [wikipedia.org] to explain why the civilisation in question stopped migrating. What's your McGuffin?

        (The most cringe-worthy I saw recently was "We're the dinosaurs that left Earth to it's Cretaceous asteroid fate, and we haven't stopped migrating." No names, no pack drill on that one, but it dirtied the hands of both colla

        • Did it? It seemed plausible to me. The Sun had a companion star, and they utilized it to build a Bowl of Heaven that could be used to travel the stars. The second book actually went into that they caused the Cretaceous disaster by returning with their "ship".

          I am wondering where they were/are going with the destination system though, that sounds...weird.

          • Well, taking off with the Bowl would itself have been sufficient to cause the K-Pg impactor, not necessarily the returning. But its probably the thick end of a year since I read it, and I'd rather given up by the time I waded though to that, so I'm not 100% sure on what was exactly the wind up. It didn't make much sense to me either.

            I don't think I'll buy the third book - if there is one. Might get it from the library, if I see it there.

    • t 5-11 million years, this new star is far too young to have undergone planet formation, let alone a highly developed civilization.

      Agree on the "highly developed civilisation". Disagree on the planets.

      Our current better models for the formation of the Solar system have it taking in the order of 20-100 Myr to have put the bulk of the planets together including forming the Moon, though locally we had a (probable) re-arrangement of gas giants at about 0.6-1.0 billion years after formation leading to the "Late

  • This star is different, it has a disk.

  • oh oh (Score:2, Funny)

    by Tablizer ( 95088 )

    EPIC 204278916

    Rats, you guessed my password!

  • By the mere fact that we have noticed this twice now (and we've looked at very few stars) would suggest this is not terribly uncommon. Even if it's one in a million, there are thousands in just our own galaxy.

    • By the mere fact that we have noticed this twice now (and we've looked at very few stars) would suggest this is not terribly uncommon.

      It's up to ten now [iop.org]. I didn't follow the references.

      Sorry, twelve, including this star and the original "Tabby's Star." Time to split the genus into species.

      • My OpenAthens subscription doesn't cover IOP, but sci-hub did the business [sci-hub.cc] for getting the full paper. And WOAH!, look at EPIC (that's the catalogue for the K2 missions) 204137184 in figs 2 and particularly 3 where it's light curve is folded onto it's principal component ! That is some seriously lumpy eclipsing variable! We live in interesting times!
  • They are two different things. The young star system would have a lot of debris in it and the star itself would be still unstable. So it is reasonable for its light output to vary. The other star was old.
  • Wouldn't a Dyson sphere require a vastly considerable amount of resource material?

    I wonder if there is not enough material in all 8 known planets plus asteroid belt to construct a Dyson sphere around our own star.
    Not to mention the inconceivable amount of other resources needed to process and construct the thing; like workers and manufacturing facilities.

    My money would be on a more naturally occurring phenomena. Perhaps a dark object(s) occluding view, or an as-yet unknown type of core reaction.

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