This is another installment in my continuing coverage of KIC
8462852 or Boyajian's star for January
25, 2017 . Several new developments have come out that are offering fresh
takes on just what's causing the mysterious dips in brightness observed to be
occurring at this bizarre star. One involves a new natural explanation to
consider and the other expands on a specific type of alien activity that could
explain a very unique and odd feature contained within the Kepler light curve.
Observations of the star continue with no new dimming events
yet detected. This is unfortunate as actually capturing a dimming event and
studying it in more detail than Kepler could is key to solving the mystery, or
would at least clear a lot of things up, see my previous videos on this subject
for information on that. But it may not be too much longer before the next
dimming event if one prediction holds true. More on that in a minute.
The first development came in the form of a paper by Brian
Metzger and his colleagues at Colombia
University in New
York . This theory is noteworthy because their paper manages
to merge two really odd aspects of the phenomenon that is happening at KIC
8462852, link to the paper in the description below. Boyajian's star isn't just
dimming, it's doing it in two different ways and that's been difficult to
reconcile with the previous natural explanations that have been offered.
On the one hand, we have the large, deep dips that the
Kepler spacecraft observed that drew scientist's attention in the first place.
But on the other, we have an apparent trend of the star dimming over all over
the course of a century based on a study of photographic plates and confirmed
by another study of the Kepler data. So we have a star that dims on both
long-term and short-term timescales. Very mysterious indeed, and Occam's razor
leads us to conclude that the two phenomena are almost certainly linked and
that places a lot of constraints on just what could be causing it.
But Metzger and his team offer an answer that has a bit more
plausibility than most of the natural theories so far put forth. They offer
that Boyajian's star has recently torn apart and eaten a planet. This would
create a situation where the star would brighten for a short period of time and
then comparatively quickly calm back down fitting the long-term dimming trend
observed with the star. It would simply be a star recovering after recently having
had a burst of energy just after dinner.
But there would also likely be debris leftover after such an
event that would block starlight more or less like what we would see in the deep
dips in the Kepler light curve. This could be disassociated material from the
torn apart planet itself or its moons and if it were in the right kind of highly
elliptical orbit it would solve a further mystery involving the lack of
infrared radiation which should be present from any small particle dusty
material orbiting the star the bulk of which the Columbia team point out could
have been blown far out into space by solar radiation where it's now simply too
cool to see in IR.
Other than one feature, the day 792 dip which is still a bit
of a head-scratcher, the Kepler light curve does look much like a young star
system surrounded by dust and gas looks. The trouble is, KIC 8462852 does not
appear to be a young star and shouldn't have this sort of debris disc around it
any longer.
That's what makes this particular theory attractive because
it allows a star like Boyajian's star which appears to be old to have a debris
disc, dim and then brighten again overall, and also undergo brief, deep dimming
events yet show no infrared heat radiating off the material.
But, as with all theories involving KIC 8462852, there's a
problem. And it's a big one. This would be a very short-term event, the planet
would have fallen into Boyajian's star between 200 and 10,000 years previous to
the dips, remember we're seeing KIC 8462852 as it was over 1200 years ago as
that's how long its light takes reach us.
This is a conspicuously short period in geologic time scales.
And while such events are bound to happen, gravity is gravity and it's a safe
bet that planets do indeed fall into stars, it should be statistically very
hard to catch such a thing in the act because it happens very quickly as far as
geologic time is concerned. You'd just have to be looking at just the right
moment to see the aftermath of a star eating a planet making this an
exceedingly rare event. You have better odds of winning the lottery than
catching something like this as it was occurring.
One thing we don't really know is how often planets fall
into stars, so it's possible that this is a more common event than we currently
think, in which case we'll have to revise our thinking on the frequency of these
sorts of events and look for more examples to corroborate it. As Dr. Jason Wright
points out on his blog, link in the description below, most stars in KIC
8462852's class would need to be regularly eating planets and they'd also have
to do it by going into highly eccentric orbits and you'd need a somewhat implausible amount of planetary material in
the universe to fit the bill. Once again, Boyajian's star throws us a curve
ball and only time and more study will clear that up.
But even if the star ate a planet, then the mysterious day
792 dip from the Kepler data is going to
take a bit more explaining than the other features in the Kepler light curve.
It really is odd and that leads us to the second development.
This one stems from something I covered in my previous
update in December and deals directly with the day 792 dip and the potential
activity of an alien civilization if this is in fact what we're seeing, which
is still on the table, though I caution remains highly unlikely, partially
because of the same problem that the planet eating theory suffers from; you'd
have to just be really lucky and happen to catch the aliens in the act which is
highly unlikely unless aliens are far more common than the Fermi paradox would
suggest. But people do win the lottery, so it's possible.
As I covered in my previous update, Dr. Eduard Heindl has
advanced a hypothesis that the activity we're seeing at Boyajian's star could
be due to stellar lifting, a hypothetical method that advanced civilizations
might employ to harvest materials from their star.
In his blog, link in the description below, he offers models
on the different dips observed by Kepler especially the odd day 792 dip that
suggest that the behavior of Boyajian's star could be indicative of an advanced
alien species using a beam to lift material from their star. But not only that,
he goes further to suggest that it would be possible to calculate the
rotational period of that beam. If this is the case, then the next dip should
begin on or around February 21st of 2017.
While I am always very cautious when I talk about the
potential for alien activity at KIC 8462852, I personally would bet money that
what we're seeing is a natural phenomenon, I would be remiss if I didn't admit
that this story would change very dramatically and become even more interesting
if that predicted dip occurs on schedule. We shall see.
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