We all know how endless our Universe is and that is the main reason why the astronomers
want to dive deeper and deeper into it in order to discover something new.
Because one thing for sure is that the more you study the universe the more you will find
out about it.
Although it is difficult to give an exact explanation what the universe is, we need
to mention that we can detect the stars, the moon, the Sun the planets that give life to
the Universe and make us always wanting to learn more and more.
This couldn’t happen without the help of astronomers who enjoy studying intergalactic
events that give answers to many astronomical questions.
In this video scientists need to give answers to something that has been discovered and
it is considered to be a mystery.
Suddenly a massive star disappeared ! Let’s start with our topic that has to do
with a Unique star.
When we look up in the sky, we can see the Sun, the Moon and the Stars and as we have
mentioned before the stars are astronomical objects consisting of a luminous spheroid
of plasma held together by their own gravity.
Consequently, the study of the birth, life, and death of stars is central to the field
of astronomy and what we know is that they are huge celestial bodies made mostly of hydrogen
and helium that produce light and heat from the churning nuclear forges inside their cores.
Stars are the most widely recognized astronomical objects, and represent the most fundamental
building blocks of galaxies.
Imagine that our galaxy, the Milky Way, contains an estimated 300 billion stars and we are
able to perceive with the naked eye, around 2.000-2.500 stars.
It is worth mentioning that stars have life cycles based on their initial mass.
For instance the larger a star, the shorter its life, although most massive stars live
for billions of years.
We do know that Stars form in huge clouds of gas and dust.
Gravity causes these clouds to contract thus drawing the gas closer.
As these materials accumulate in the center, density raises and pressure increases.
This causes the matter to heat up and glow while the mass increases.
Temperatures and pressure continually grow until hydrogen can be fused.
The heat generated by this nuclear fusion causes the gas to expand and when hydrostatic
equilibrium is reached, the star is born and we are able to observe and analyze them.
One of these stars, is known as Kinman Dwarf or PHL 293B.
The reason why we are going to pay attention to this specific star, is because something
extraordinary happened…and our job here is to give further details as what happened
seem to be difficult to comprehend.
So let’s take things from the beginning and let the journey begin.
Before we continue with our exploration to PHL 293B star, be sure to like or dislike
the video so that we can continue improve and make these videos better for you the viewer.
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The PHL 293B star belongs to the dwarf galaxy in the constellation of Aquarius and it lies
approximately 75 million light-years away.
Let’s see on a closer look this galaxy.
A dwarf galaxy is a small galaxy composed of about 100 million up to several billion
stars.
Dwarf galaxies' formation and activity are thought to be heavily influenced by interactions
with larger galaxies.
Astronomers identify numerous types of dwarf galaxies, based on their shape and composition.
A good example of a dwarf galaxy is the Large Magellanic Cloud, located about 160,000 light-years
from Earth.
It contains about 1/10th the mass of the Milky Way, and has about 10% of its stars.
Two other dwarf galaxies are even closer to the Milky Way, and have been captured by our
galaxy’s gravity.
Other dwarf galaxies are just remnants that have been torn apart by the Milky Way’s
gravity, and are currently being incorporated into the structure of our galaxy.
The massive star called PHL 293B, is one of the brightest and largest star known until
today and many astrophysics claim that we may have detected one of the most massive
stars of the local Universe going gently into the night.
In this point we need to mention that massive stars are among the most important sources
of ionizing photons and chemical elements, producing a significant proportion of the
elements currently present in the Universe.
They are instrumental to the understanding of a variety of astrophysical topics, including
the link between supernova and gamma-ray bursts to the nature of their respective progenitors
as well as the early evolution of the Universe.
Let’s go back to the PHL 293B star now.
The star is considered to be 2,5 million times brighter than our sun and scientists have
been studying PHL 293B for a long period of time.
To be more specific, in the 2000-2010s, astronomers started observing the giant star and all these
ten years they have been studying this mysterious star in this galaxy and their observations
indicated that the star was shining brightly especially between 2001 and 2011.
Different teams of astronomers were regularly observing this star to obtain more information
and they discovered that this star is in a late stage of its evolution.
So you can understand that there was curiosity for this star for some reason.
And astronomer’s curiosity led to a discovery that would become the beginning of another
scientific exploration.
What I am saying is that in 2019 Eso’s very large telescope couldn’t find the star.
When they tried to study it once again PHL 293B was no longer at its place and there
was no trace.
For some reason it suddenly disappeared and they could no longer find signatures of the
star.
It came as a surprise the fact that the star had disappeared.
And something really interesting is that there were no signs of a star explosion.
The star was located 70 million light-years away from our planet but still we were able
to detect it.
And astronomers aren’t sure why the star is invisible.
It's a little hard to figure out exactly what happened and it is even harder for astronomers
to understand why this star vanished.
And the reason why it is difficult for them to understand how it disappeared, is because
stars cannot disappear like this in an instant moment especially this star that was observed
by astronomers for over a decade.
It would be highly unusual for such a massive star to disappear without producing a bright
supernova explosion.
Typically, at the end of a star's life, it will go supernova before turning into either
a black hole or neutron star.
This violent stage is hard to miss and can last for years.
Astronomers likely would have caught sight of the explosion.
A question that needs to be answered is how were we able to detect the vanishing of the
star?
Being located 75 million light-years from Earth means that astronomers are unable to
distinguish individual stars within the Kinman Dwarf galaxy, but they are able to determine
signatures from those stars, and crucially, in this case, can tell when one of those signatures
is missing.During the observations made between 2001 and 2011, the signature of a luminous
blue variable star was distinguishable in the galaxy’s light output.
Astronomers were also able to determine that the blue variable star in question was around
2.5 times brighter than our own star.Even though blue variable stars such as this one
are unstable and show sometimes dramatic shifts in their spectra and brightness, even with
these changes accounted for researchers can spot the traces of such an object.The team
used the Echelle SPectrograph for Rocky Exoplanet and Stable Spectroscopic Observations (ESPRESSO)
instrument attached to the VLT to make their initial observations in August 2019.
Failing to find the star’s signal with ESPRESSO — one of the most powerful and precise planet-hunting
devices on Earth — the team followed up this initial investigation with VLT’s X-Shooter
instrument.
This follow-up search confirmed their findings.
Using the European Southern Observatory's Very Large Telescope (VLT), astronomers have
discovered the absence of an unstable massive star in a dwarf galaxy.
This discovery wouldn’t have been made without using the powerful ESO 8-metre telescopes,
their unique instrumentation, and the prompt access to those capabilities following the
recent agreement of Ireland to join ESO.
It is worth mentioning that Ireland became an ESO member state in September 2018.
Based on their observations and models, the astronomers have suggested two explanations
that could be distinct possibilities for the star's disappearance and lack of a supernova,
related to this possible outburst.
The outburst may have resulted in the luminous blue variable being transformed into a less
luminous star, which could also be partly hidden by dust.
So it has been suggested the star may have been shrouded in a thick fog of gas and dust,
obscuring it from view.
Near-infrared observations taken in 2009 suggest this cloud of gas and dust would need to be
extremely cold in order to shade the star undetected
Alternatively, the team says the star may have collapsed into a black hole, without
producing a supernova explosion.
, however, evidence has started to emerge that stars can indeed collapse directly into
black holes without undergoing a supernova explosion.
It's not impossible that the star underwent an undetected supernova, but such a massive
star as a luminous blue variable would be expected to produce a supernova afterglow
that shines in the sky for at least five years following.
This would be a rare event: our current understanding of how massive stars die points to most of
them ending their lives in a supernova.
So there's a really exciting possibility that the star collapsed down into a black hole,
without the supernova that has previously been thought a necessary component of such
events.
The old data indicated that the star in the Kinman Dwarf could have been undergoing a
strong outburst period that likely ended sometime after 2011.
Luminous blue variable stars such as this one are prone to experiencing giant outbursts
over the course of their life, causing the stars' rate of mass loss to spike and their
luminosity to increase dramatically.
If something like this is true, that means that this would be the first direct detection
of such a monster star ending its life in this manner.
It would be part of astronomical history as If this is the case, then not only must these
events be extremely rare, it could challenge what we know about the death of stars!
Something new to be added to the discoveries of astronomy!
I think it is very fashinated.
It's impossible to know for certain with the current data.
Only future observations across a range of wavelengths can shed light on the mystery
of the missing star.
Future studies are needed to confirm what fate befell this star.
Planned to begin operations in 2025, ESO's Extremely Large Telescope (ELT) will be capable
of resolving stars in distant galaxies such as the Kinman Dwarf, helping to solve cosmic
mysteries such as this one.
Fortunately, investigations into this stellar disappearance are set to continue.
The ESO’s Extremely Large Telescope (ELT) is due to begin operations in 2025, and it
should be powerful enough to resolve individual stars.
Based on these findings, the ELT will undoubtedly be turned towards the Kinman Dwarf galaxy
in search of this missing star to determine its final fate.
As we are coming to an end, we need to say that this isn't the first time a star has
completely vanished without a trace.
In 2017, astronomers were stunned when a red giant star 22 million light-years away in
the Fireworks Galaxy suddenly disappeared.
Thanks for watching everyone!
I would really like to know your opinion regarding PHL 293B star disappearance.
I want to know your feelings about the disappearance.
Do you think it is something that makes sense?
Do you feel like we are going to find an answer to what happened to this star?
Let me know, in the comments below, be sure to subscribe, and I’ll see you next time
on the channel!