Montag, 22. Mai 2017

Dip in May brings Ideas away

What changed due to 2017 May Dip?


The most exciting thing of the May Dip is, that we now know for sure, the dips at KIC 8462852 are not a Kepler measurement artifact, the Dips are real.
This helps a lot, because there is nothing as frustrating as a stupid measurement. I remember the neutrino experiment in Italy, where the speed of light as defined in Einstein's theory was in doubt, only to learn a few weeks later, that a cable was not connected as proposed.

Time and timing

The next big thing is, that the timing of the dip was not unexpected. The main dips of Kepler happened at day 792 (2011/03/05) and in a time window between day 1518 and 1570, with a strange symmetric peak at day 1539. If the time between this events is in some sense the same, and I try hard not to be to specific, than we can propose a period somewhere in the range of 750 to 770 days. Assuming, that we missed a dipping event in 2015 due to the late detection of the strange star by citizen scientists, the next events should take place in the first half year of 2017

Dips during the second big dip period between d 1518 and d1570 [1]

But the new dip seems not to be a deep dip beyond 10% flux reduction. The measurement suggests only a <3% dip. 
The dip has about 98% at peak dipping. (Source: Jason Wright, Twitter)
It should be noted, there have been many dips during the four year period of the Kepler mission with dips of less than 1%, at Tabby's Star, for details see "Meditation over Tabby's Star".

The second interesting thing is the length of the new dip, it seems to last about seven days, when we assume the soft start at 16 May 2017 and the sharp end at 19 May 2017 as shown in the graph above. This timing matches the mysterious  dip of day 792 [2] very well, a dip that lasted also seven days! It is hard not to believe that this is not a coincidence.

Superposition of dip d792 and the May 2017 dip. Be aware of the scaling and sorry for the poor design.
As long as we don't register a stronger peak we can hardly say anything about the internal shape. It may be, that the combination of all available results from multiple sources reduce the error bars significant. 

The spectrometric results are not public in the moment, the only information I could gather is, that there is no significant absorption line and infrared might show a lower absorption as visible light.


Which Hypothesis get stronger, which one loose?

There is a very long list of hypothesis [2] what is going on at KIC 08462852. Let me give my judgement, what has changed at the state of our knowledge today (22 May 2017):

  • A object in our local solar system: This seems not to be the case, given the periodicity of 2 years and the knowledge of our solar system. Hypothesis gone!
  • A cloud in the interstellar medium (ISM) in between us and the star. Due to repeated measurement of the signal very low possibility.  Hypothesis not worth to mention any more!
  • Black hole, Hypothesis gone!
  • Comets: This is a tricky one, there are no new supports to a comet, but an other observation should here be mentioned: Beside the new dip event, it seems, that the star is still under a global dimming regime as observed by large telescopes. This could hardly be explained by comets. Hypothesis very low chance!
  • Planet collision: The big question is, where is the infrared signal! Hypothesis very low chance!
  • Star is changing its behavior: We have no model, how a star of that size and age could do that, in addition, the new dip does not support this hypothesis. Hypothesis gone!
Remaining: 
  • Something we have not thought about
  • Very special thin dust cloud (ring structure) interacting with a magnetic field
  • Large scale Dyson structure of unknown shape (not very good matching the data)
  • Star lifting by natural or artificial cause (My favorite)
Star Lifting: Eduard Heindl, A physically inspired model of Dip d792 and d1519 of the Kepler light curve seen at KIC8462852, 2016, https://arxiv.org/abs/1611.08368

Comments?

I am very happy, if you comment on my ideas.

References
[1] Gary D. Sacco, https://www.reddit.com/r/KIC8462852/comments/56kdfw/95_day_abnormal_equilibrium_of_periodicity_and/
[2] Jason T. Wright, Families of Plausible Solutions to the Puzzle of Boyajian's Star
    https://arxiv.org/abs/1609.03505
[3] Eduard Heindl, Blogpost 2017, Dip 792 http://some-science.blogspot.de/2017/05/dip-792-at-boyajian-star-kic-8462852.html


Kommentare:

  1. Star lifting by natural or artificial cause is my favority too. Great!

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  2. hi Dr Handel! this was really interesting to read, thank you for writing it up. :) i don't know if you were including the photometry in your analysis of the spectroscopy results, but in case you weren't -- Dr Boyajian says that there was more of a dip in the blue filter and less dipping in the i' filter (https://twitter.com/tsboyajian/status/866390381063229441). what do you make of that, if you have any thoughts on it?

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    1. oh my goodness i just caught that i completely messed up your name -- Dr Heindl! i apologize, i must have zoned out while writing my comment, haha

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    2. If it is star lifting, the dust part should absorb more blue than red light. I have no timing information about the spectras to give a valuable comment at the moment.

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  3. If the Calcium H and K lines did not change, does that rule out sunspots? I mean starspots

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  4. To me the so-called SR71 event looks like the light curve signature of a planet with a somewhat dense ring structure oriented 90 degrees to our line of sight. Not so?

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    1. The light curve of day 1539 (SR71) is compatible with a Saturn like system. But it does not help for the other strange dips.
      I think a 90 degree shift is also hard to understand using celestial mechanics.

      It seems not very probable, that we see two very different things at the same star by accident.

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  5. An idea i wouldn't have heard yet, but not sure if that would be possible:
    What if there are 2 gasgiants that rarely get very very close to each other. Could their gravitational force be strong enough to "stretch" their gasatmospheres over a long distance until the 2 seperate again and the planets take some time to recapture their gas ?

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  6. You mention natural or artificial star lifting as your preferred hypothesis. What is a possible natural cause of star lifting?

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    1. We see protuberance phenomen at our sun, mater is lifted by magnetic fields. I can imagine some special magnetic circumstances guiding the mater up to an orbit.

      Not clear in detail, but research worth.

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    2. I came back to this article specifically to ask that question, Steven Frank. Thanks!

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