What caused the betelgeuse dimming anomaly?
Updates Betelgeuse has been a center of attraction
and research for the scientific community in recent years.
The red supergiant Betelgeuse, 642 light-years distant, inexplicably started to dim around
the end of 2019, losing up to 60% of its regular brightness.
Something really remarkable for a star that is among the ten brightest visible from Earth,
and had led scientists to assume that its supernova explosion is near.
The initial explanations and theories talked about some kind of large emission from the
star that produced lots of dust and blocked the light coming from it, causing the strange
dimming effect.
We also made a video about the most recent explanation observed from the data obtained
from Hubble, so make sure to check that out too.
Even if this is precisely what happened here, we still don't know why this happened or why
the star had such an extraordinary emission.
The real impact was fairly dramatic; the star on the right is what it looked like at its
darkest, making this one of the most intriguing mysteries of the previous several decades.
Could it be a passing black hole that might have caused the emission from the star? or
a swallowed planet?
Let’s talk about all that and more.
The star Betelgeuse faded by roughly 60% in late 2019.
While no one can tell for certain what caused the emission from the star, fresh study reveals
that a roaming companion may have had a role.
The intruder may have caused a tidal bulge by swinging near to the big star, causing
the surface of Betelgeuse to darken.
While this scenario cannot account for the whole amount of dimming seen, it may have
had additional impacts on the star that exacerbated the situation, according to researchers in
a recent report.
Betelgeuse is one of the most readily identified stars in the night sky.
It is seen as Orion's blazing red shoulder and is normally the 10th brightest star in
the sky.
In our solar system, the red supergiant would swallow all of the inner rocky planets and
spread from the sun to the asteroid belt between Mars and Jupiter.
Betelgeuse is nearing the end of her life.
It's massive because it long ago ceased fusing hydrogen in its core and moved to fusing helium.
A shell of burning hydrogen surrounds the center.
The energy from the fusion events in and around the core pushes the outer layers of the atmosphere
outward, pushing the star to expand.
When the star reaches the end of its red giant phase, it will explode as a Type II supernova,
which occurs when the core of a star can no longer generate enough energy to "sustain"
its enormous mass, which collapses due to its own gravity until the star, unable to
withstand the immense pressure, explodes, releasing an enormous amount of energy.
When the star started to fade for no apparent reason towards the end of 2019, scientists
assumed the end was near.
Betelgeuse's brightness continued to fall until early 2020, but the dimming ended in
February of that year, when its brilliance was just 60% normal, and the star gradually
started to recover.
Today, its brightness has returned to normal levels.
These photos, obtained with the SPHERE instrument on the Very Large Telescope of the European
Southern Observatory, depict the surface of the red supergiant star Betelgeuse during
its exceptional dimming in late 2019 and early 2020.
The picture on the far left was obtained in January 2019 and shows the star at its typical
brightness, but the subsequent photographs were taken in December 2019, January 2020,
and March 2020, when the star's brightness had declined significantly, particularly in
its southern quadrant.
In April 2020, the brightness restored to normal.
Astronomers have Betelgeuse data dating back half a century, and they found no precedence
for the 2019 occurrence.
So whatever caused the "Great Dimming," as it became known, had to be something spectacular.
Whatever caused the dimming has to have occurred from somewhere outside the star, rather than
from a fundamental alteration in Betelgeuse's internal activities.
This is due to the fact that modifications to the fusion processes do not occur in a
matter of months.
The core just has too much mass, and the energy generated by fusion processes are simply too
great, to sustain such rapid fluctuations.
Many theories have been advanced by astronomers, including star explosions and enormous clumps
of orbiting material.
One explanation is that the form of Betelgeuse's outer atmosphere altered, creating a brightness
shift.
The brightness of a star's atmosphere is determined by the distance between the outermost layer
and the nuclear core (and any surrounding shells) at the centre.
This is due to the fact that stars are not solid things, but rather massive balls of
gas.
The weight of their own gravity holds the stars together, but that force is counterbalanced
by the (literally) explosive energy unleashed at their cores.
As a result, the surface of a star is constantly balanced between these two forces.
The location of the equilibrium point affects the temperature of the star, and the temperature
controls its brightness.
When stars revolve too rapidly, astronomers can observe the consequences.
When they do, the rotating force causes their equators to bulge out relative to their poles.
As a result, the star's equator moves farther from the core, lowering temperatures and,
as a result, brightness.
Because of this "gravity darkening," certain stars look brighter near their poles than
in their centres.
Betelgeuse isn't spinning rapidly enough for this to be a concern, but other factors may
cause bulges on the side of a star.
If a chance visitor, such as a tiny black hole, swung too near to the star, it might
generate tides on the surface in the same manner as the moon does on Earth.
With the tidal bulge in place, the equator would darken, as would the star's overall
appearance.
However, after the visitor had departed, Betelgeuse could return to normal, with all of its atmosphere
in the proper locations, and begin its typical abundant radiation production.
This scenario was explored by a group of astronomers, and their findings were published in the journal
Monthly Notices of the Royal Astronomical Society.
The scientists decided that the mass and velocity of an unknown, concealed guest quickly swinging
into the Betelgeuse system couldn't account for the whole 60% dimming.
However, the visitor's passage might have resulted in other impacts, such as a powerful
star outburst.
A massive volume of ejected debris, together with gravity darkening induced by tidal processes,
might have momentarily blocked our vision of Betelgeuse, explaining the Great Dimming.
Another plausible explanation of the emission from the star is that it might have swallowed
a planet.
Betelgeuse has evolved over the past many thousand years.
It seems to have changed its color in comparison to some of the previous views from Chinese
observers, suggesting that Betelgeuse may have just recently reached this stage and
implying that it will remain in this stage for a very long period.
In other words, if these observations are right, it will not go supernova for thousands
of years.
If it has just recently reached this very active and relatively big stage, there is
another very significant inference from all of this, and it has something to do with what
you could observe near Betelgeuse.
It's possible that some planets formed organically here early on.
It's evident that it never had planets, and there's probably no direct way to find out
right now, but presuming that it did, it most likely ended up swallowing some of them as
it grew, quite recently within the past few hundred years.
This was explained in considerable detail in an interesting recent publication.
It basically outlined what happens to certain stars enormous stars when they swallow certain
planets, and they discovered that if the planet is really huge and massive, the star itself
would begin to have unexpected effects on the surface and maybe even act in extremely
chaotic ways.
This, in particular, may disrupt the star's spin and potentially modify its chemical makeup.
It can really generate a lot of unbinding energy, which ends up releasing massive amounts
of atmosphere.
It's possible that a large planet was swallowed by Betelgeuse in the last few hundreds of
years, and that planet is generating part of the disturbance we're witnessing with the
piece then going loose.
Because the planet was devoured and is now churning the star from inside, some of the
pieces of the star were practically pushed off and escaped into deep space.
However, for the most dramatic consequences, the planet would need to be extremely big,
essentially a brown dwarf.
A terrestrial planet would very certainly not enough, but if Betelgeuse was orbited
by a Jupiter-like object or perhaps something more massive than Jupiter, namely a high Jupiter,
this may explain at least some of these phenomena.
Astronomers may never completely comprehend what occurred in late 2019.
After all, that occurred just once in all of the great star's records.
More observations of Betelgeuse and other red supergiants like it might lead to an answer.
While the combination of gravity darkening from a tidal bulge caused by a near encounter
with a black hole and the accompanying eruption of shrouding material may seem far-fetched,
we can only invent the best narrative we can with the facts we have.
SO what do you think about this mysterious dimming of Betelgeuse?
Let us know what you think in the comment section below and share the video with your
friends!