Thursday, January 14, 2016

Episode 27 - The Slow and Fast Dimming of Tabby's Star

Released: 14 January 2016
Duration: 62 minutes 4 seconds

Download the .mp3 audio file

Host Paul Carr talks to Dr. Bradley Schaefer about his research showing a dramatic dimming of
Bradley Schaefer
Tabby's Star over a century. This all but rules out any explanation anyone has put forth so far for the short term dimming of the star found in the Kepler data by Boyajian, et. al.


KIC 8462852 Faded at an Average Rate of 0.165+-0.013 Magnitudes Per Century From 1890 To 1989
Where's the Flux? (paper by Boyajian, et. al.)

Centauri Dreams Discussion
KIC 8462852 - The Infrared Flux
IRTF/SPEX Observations of the Unusual Kepler Lightcurve System KIC8462852
Constraints on the Circumstellar Dust Around KIC 8462852


I'm Not Saying it Was Aliens (Unseen Podcast panel discussion of Tabby's Star)


No Signal Found from KIC8462852

Bradley E. Schaefer

Update: Hippke and Angerhausen disagree:  KIC 8462852 did likely not fade during the last 100 years

Further Update: Schaefer responds to Hippke on Centauri Dreams.

Further, further update: Hippke paper is revised in response to comments & We interview DASCH PI Josh Grindlay.

Host and Producer: Paul Carr
Music: Dj Spooky, Jason Robinson, Mike Griffin, George Hrab


  1. It all seems (to me) that there is "Insufficient Data". We need more observations. Ideas are good but there seems to be a lot of speculation going on here.

    1. There is certainly sufficient data for the findings of the paper.

  2. I don't understand how something can be "Identical with the exception of timescale. The timescale is critical to me. Am I wrong about this?

  3. Excellent work by Paul Carr in getting this episode recorded and published on the very same day that the pre-print of the academic paper appeared on the online Astro-ph
    I love a good mystery, and this seemingly ordinary F type main sequence star has certainly provided us with one. I find the subject matter to be fascinating and in the absence of a compelling reason for the observed dimming of this star I fully expect this story to run and run.
    Bravo to Dr Schaefer for his heroic trawl through the archived Harvard photographic plates of the night sky. His work proves that the DASCH project to digitise these plates has provided astronomers with a treasure trove of data.

  4. Thanks, Adam. The Wow! Signal production staff is pretty sleepy this morning, but that's why they get the big bucks.

  5. Great episode !
    I suppose the lack of IR excess rules out alien megastructures ?

    I disagree about the use of Occam's Razor here though. The two different timescales seem so different I can't see a good reason to connect the two - they might be related, they might not. Both possibilities should be given equal weight. Not that that makes comets any more likely though, for all the reasons given.

    Maybe a simpler way to rule out comets over a long timescale : why would they cause a steady dip ? I can see why they'd cause day-long dips in the brightness which then returns to its exactly pre-dip level, but why a slope in the overall brightness ?

    Fascinating object, whatever's really going on...

    1. Thanks, this was the first completely unscripted episode I have done, although I had multiple takes on some of the intro stuff, and edited out some rambling. I just felt I should jump on the story for some reason.

    2. I'm still trying to understand the IR excess story. There may be a little bit of IR excess, but so far nothing statistically compelling:

  6. So by inspection of figure 1 the present B is greater than 12.5?

    1. B magnitude been reported at 12.26 in Boyajian, et. al.. I don't the dates for this observations, but they were recent.

  7. You can not put a shell around a lightbulb, let alone a star and somehow make the energy vanish. You can use high quality energy to do work but the energy still exists as heat after the job is done. Even a super alien would find that keeping energy inside a shell is pretty impossible pretty quickly.

    Now if energy could be converted to matter...and that matter was used to build a shell...wouldn't it be interesting if it worked out to a dimming in the 0.15 mag per century range. Looks like magic but there it is

  8. I just saw Jason Wright's treatment of this on Centauri Dreams....Nevermind : )

    Great interview btw/ I could listen to Dr. Schaefer all day