The mysterious dimming of Betelgeuse has been solved!
The mysterious event began back in 2019 and we already made some videos about the reasons for
this last year. But new evidence and data from Hubble has come to light that explains
the dimming of this Red Giant and answers the question about what caused this event.
Now NASA’s Hubble telescope has released new data and
information about this red giant’s mysterious phenomenon. Let’s talk about that and more.
Betelgeuse is one of the closest large stars to Earth, located around 700 light years distant.
It's an ancient star that has reached the stage where it radiates a dull red and expands, with the
hot core's gravitational grasp on its outer layers very fragile. The star has a heartbeat, albeit
one that is incredibly sluggish and erratic. The star's surface expands and shrinks at different
times over time. One of these cycles is quite regular, lasting little more than five years.
A shorter, more irregular cycle follows, lasting from less than a year to 1.5 years. Even though
these cycles are easy to track with ground-based telescopes, these shifts do not cause the radical
changes in the star’s light as was observed during the dimming event? What caused it then?
Betelgeuse appears as a dazzling, ruby-red, sparkling pinpoint of light
on the upper right shoulder of Orion the Hunter in the winter sky. Close inspection reveals
it to be a seething beast with a 400-day-long pulse of regular pulsations. This aging star is
classed as a supergiant because it has grown to an incredible diameter of around 1 billion miles. If
put at the center of our solar system, it would reach Jupiter's orbit. The ultimate phase of the
star Betelgues is a Supernova. When this occurs, it will be so strong that it would be visible in
the midday sky from Earth. But, before the ultimate detonation, scientists have been
observing a lot of fireworks already going off. With the help of Hubble and other observatories,
Astronomers determined that the star blasted off a large portion of its visible surface out into
space in 2019. This was a first time thing for a star, astronomers had seen nothing like this.
Our irritable Sun frequently undergoes huge ejections of its outer atmosphere,
the corona. However, such events usually known as Coronal mass ejections are orders of magnitude
weaker than what was observed for Betelguese.Scientist were puzzled over the
phenomenon and wondered whether the star was going to explode soon as a supernova. They were able to
narrow down the possible explanations to two: a short-lived cold area on the star's southern
surface (similar to a sun spot) or a clump of dust making the star appear dimmer to viewers on Earth.
When more observations about the star were made using other frequencies such as infrared,
it was found that not much had actually changed around the star suggesting that it wasn’t going
through a major change and it would most definitely not explode as a supernova,
not until the next 10,000 years at least. Following several major observations at various
frequencies and very thorough investigations by some of the world's best scientists,
it was more or less confirmed that what was happening to Betleguese was most likely the
result of a mid-remission from the surface, which resulted in a relatively large dust cloud.
When this dust cloud was ejected from the surface, it obstructed the star very effectively,
thus causing the overall dimming effect. This theory was accepted by everyone, as it made sense
and was backed up by observations from multiple telescopes. But there was still one question:
what precisely occurred to Beetlejuice three years ago that might have caused this phenomenon? And
more importantly will it happen again? That’s what a recent NASA paper aims to answer.
This study was conducted by the famous scientist who was the first ever to image the surface of
Betelgeuse using the Hubble telescope back in 1996. They were even able to produce the beautiful
images of Betelgeuse resolving the sunspots on its surface. So the same group of scientists observed
this star again to resolve this mysterious event. In this case though, they used many
observatories apart from Hubble. This includes new spectroscopic and imaging data from the STELLA
robotic observatory, the Tillinghast Reflector Echelle Spectrograph (TRES) at the Fred L. Whipple
Observatory, NASA's Solar Terrestrial Relations Observatory spacecraft (STEREO-A), NASA's Hubble
Space Telescope, and the American Association of Variable Star Observers (AAVSO). But the data from
Hubble was the most helpful in this case and the one that was able to help us resolve it.
In terms of physical mass Betelgeuse has at least 16 times the mass of our sun and is not especially
spherical, as is typical of very massive stars. In fact, there was a research not long ago, just
a few months ago, that demonstrated that for these really, really huge stars, determining where their
core is often rather difficult. In astronomy, scientists normally search for the center of
brightness to locate the core of the star, however for a typical red giant starlight beetlejuice,
the real center of brightness, the point of greatest luminosity, tends to hop about
or practically dance around, making establishing where the actual star is located and so measuring
its distance difficult, implying that these stars are just incredibly active. They're quite
unexpected, and they're not especially stable in terms of form and activity on the surface.
They're highly dynamic and change all the time, which is why it doesn't appear like a sphere here
and more like an interesting blob, a blob that's not especially thick.
Analyzing the data from Hubble, scientists were able to confirm that Betelgeuse was shedding a
significant portion of its visible surface and causing a massive Surface Mass Ejection.
This has never been seen before with any type of star. As compared to the Coronal mass ejections
of our sun, Betelgeuse’s Surface Mass ejection blasted 400 billion times more mass into space.
When such a massive amount of mass left the star's surface,
it very likely fractured a large portion of the star's photosphere, with the gas then cooling down
to form a dust cloud, which essentially blocked the light from the star as seen from Earth,
with the dimming effects lasting only a few months. This particular event,
the first of its kind ever observed, has also had a significant impact on the star, with Betelgeuse
still recovering from it all. For example, various convection cells present inside the star that
normally drive pulsation and material circulation may have been disrupted by this event and are
still sloshing around uncontrollably, unable to produce regular pulsations.
These new findings provide light on how red stars lose mass when their nuclear fusion furnaces burn
out before exploding as supernovae. The quantity of mass lost has a big impact on their fate.
Betelgeuse's uncharacteristically petulant behavior, on the other hand, is not proof
that the star is poised to explode anytime soon. As a result, the mass-loss event is not always
indicative of an impending explosion. Scientists are now piecing together the jigsaw pieces of
the star's obstinate behavior before, during, and during the eruption to form a cohesive tale
of a never-before-seen colossal convulsion in an aged star. A convective plume more than a million
miles broad, boiling up from deep within the star, may have generated the 2019 epic outburst.
It generated shocks and pulsations that blew the chunk of photosphere away,
leaving the star with a big cold surface area beneath the dust cloud created
by the cooling portion of photosphere. Betelgeuse is now recovering from this injury.
The broken portion of the photosphere, which weighed about several times as much as our Moon,
flew off into space and cooled to create a dust cloud, which obscured light from
the star as seen by Earth watchers. On top of this, the supergiant’s 400-day pulsation rate
has vanished, at least for now. For about 200 years, astronomers have seen this pattern in
fluctuations in Betelgeuse's brightness and surface movements. Its destruction attests to
the blowout's intensity. According to Dupree, the star's internal convection cells, which
cause the regular pulsing, may be swirling around like an unbalanced washing machine tub.
The TRES and Hubble spectra indicate that the outer layers have returned to normal,
but the surface is still bouncing like a dish of gelatin dessert while the photosphere rebuilds.
Betelgeuse has grown so large that if it replaced the Sun at the center of our solar system,
its outer surface would stretch beyond Jupiter's orbit.
In 1996, Dupree utilized Hubble to resolve hot regions on the star's
surface. The first direct picture of a star other than the Sun was obtained.
To know even more about the mysterious events we can also use NASA’s James Webb Space telescope
to detect the ejected material in the infrared spectrum as it continues to move away from the
star. And just to be clear once again the outburst does not indicate that Betelgeuse will become a
supernova very soon, but it does demonstrate how ancient stars lose material. If Betelgeuse dies
in a stellar explosion, the light will be visible from Earth during the day, but the star is too far
away to have any further effects on our planet. So what do you think about this mysterious dimming:
Will the James Webb be used to further observe the star? Will we ever be able to solve the mystery?
Let us know what you think in the comment section below and share the video with your friends!