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The James Webb Space Telescope
revealed the most detailed portrait of the Tarantula Nebula.
And I'm not going to lie, of all of the incredible images
that Webb has released thus far, this one’s my favorite.
Although there is a new image of the Orion Nebula
that I should probably tell you about,
but we'll get to that later, so make sure you stick around.
Like Orion, the Tarantula Nebula is a region of hot ionized gas that's
being blasted by a group of recently formed hot, massive young stars.
Such regions are called H II regions because the Roman number two
is how we designate that an atomic element has been stripped
out of one of its electrons because of ionization.
So the whole thing is just glowing.
H II regions are not only beautiful, but they are natural laboratories
in which to study star formation.
And 30 Doradus is a particularly interesting laboratory
because it's chemically similar to the gigantic star forming regions
that existed when the universe was only a few billion years old.
This period is known as the Cosmic Noon because it was the peak of star formation
in the early universe.
But not only is the tarantula a throwback to the good old days of star
formation, but it's close enough for us to study it in some detail.
The Nebula resides 160,000 light years away in the large
Magellanic Cloud, which itself is a satellite of the Milky Way Galaxy.
The Tarantula gets its nickname from its spider-like appearance.
And it's a very giant spider indeed.
At nearly 1900 light years across the Tarantula
dwarfs nearby H II regions like the Orion Nebula.
In fact, if the Tarantula were at the Orion Nebula's distance from Earth,
it would be bright enough to cast shadows at night.
But even at its actual distance of 161,000 light years,
the Tarantula is still much too large for Webb to image all at once.
However, Webb was able to bring three of its instruments to bear
on the central region and pierce through the veil of much of the obscuring gas.
The NIRCam mosaic captures a region about 340 light years across.
The result is the clearest and most detailed look at the clouds, the.
protostars within them, and the winds and jets that these stars are generating.
In fact, it really does look like an enormous spiderweb.
Oh, and if you haven't done so already, I invite you
to download the nearly 15,000 by 8400
pixel full resolution image and just get lost in it for a while.
The image is dominated by a large central cavity.
This region is being swept out by the large cluster of massive stars
to the right.
In fact, the Webb data is so detailed, it kind of looks three dimensional,
as if you were going into a cosmic tunnel.
The central cluster, dubbed R136,
consists of
72 Type-O and Wolf-Rayet stars
that are crammed within a five parsec-wide region
that's only 16 light years across.
Yet the stars within it produce the majority of the intense ultraviolet
radiation that is ionizing the surrounding nebula.
And not only that, but the stars blast the surrounding gas with stellar winds
that are really more like stellar hurricanes.
Any low density gas is either completely ionized
or pushed away, opening up the cavity.
Only the very densest clouds that immediately surround the stars
of the cluster remain, but they're still getting blowtorched.
So come back in a few ten thousand years and all of that gas will probably be gone.
The stars of the R136 cluster are truly, staggeringly massive.
In fact, recent work showed that its largest star, R136
a1 has a mass anywhere from 169
to perhaps as much as 230 solar masses.
Even at that lower range, his makes R 136 a1 the most massive star that we know of.
R 136 is just that central part of a much larger
cluster called NGC 2070.
The Hubble Space Telescope showed that there are at least
two clusters in the process of merging.
The clusters mass is estimated at around 450,000 Suns.
Models show that mergers of giant clusters
like these can over time lead to a collapsed core
at the center, surrounded by a spherical distribution of stars.
In other words, we may be seeing a Globular star cluster under development.
That alone is an amazing prospect because all modern globular
clusters are made of stars that are much older than our Sun.
All of their massive, hot, blue stars that formed In
the cluster would have exploded as supernovae billions of years ago.
The stars that remain the globulars today are of the cooler, less
massive variety that are able to live much longer.
But the stars of NGC 2070 are no older than 2 million years.
And that gives us a rare chance
to watch a globular cluster forming in the present day universe.
But there is one notable exception to the hot blue stars
that dominate the Tarantula.
At the top of the main cavity is an evolved red giant star
that's near the end of its life.
In Webb's NIRCam image, the star becomes the brightest object in the picture.
And that's because its surface temperature is much lower
than the surrounding stars.
So the red giant is actually the brightest in the near-infrared,
and it outshines everything else in the image.
In fact, it's so bright
that it's able to generate Webb's eight-spike diffraction pattern.
If we follow the top spike, we arrive at another large
bubble of gas that surrounds a mini cluster of protostars.
These protostars are still enclosed by dusty material,
but they're blowing out this enormous bubble.
So in a real sense, what we are looking at is effectively
the next generation of stars that are forming
within the nebula farther from the central region.
The gas is cooler and becomes much more dense,
and this gas radiates at even longer wavelengths.
So it takes on a red, rusty color in the image.
And this longer wavelength light tells us that the nebula is rich
with complex hydrocarbons; think smoke and light dust.
And this material is getting
piled up by the winds from the hot, massive stars in the center.
Most of these dense clumps will later collapse and form future stars.
But to see even deeper into these clumps, Webb used its MIRI instrument
to view the region at mid infrared wavelengths.
The bright stars largely disappear because they produce very little of their
light at these longer wavelengths, while the cooler hydrocarbon gas brightens.
Because this is taken with a different instrument, the hydrocarbon gas is colored
blues and purples, while cooler gases are colored red.
MIRI lets us glimpse protostars that are embedded in these knots
and we're seeing these stars for the very first time.
These stars are still accreting matter from their surrounding cocoons.
As they do so, they gain mass and are squeezing their cores harder and harder.
One day the temperatures in the cores will rise to the point where hydrogen
will begin fuzing the helium, producing energy in the process.
At that point, the star will officially be born.
Now, because MIRI sees at longer wavelengths,
its images simply can't be as sharp as NIRCam’s
because the longer the wavelength, the lower the resolution.
So on the one hand, MIRI is always going to be fuzzier than NIRCam,
but thanks to Webb's six and a half meter mirror,
MIRI's images are the sharpest ever made at these longer wavelengths.
The whole MIRI image just takes on this ghostly, ethereal vibe,
and all of the structures within just make the Tarantula feel
even more three dimensional.
But if that weren't cool
enough, MIRI (correction: Webb) used its Near Infrared Spectrograph
to find out what's really going on inside a particular region in the nebula.
This structure has been hypothesized to be a large bubble
that's being blown out by the protostar within.
As protostars get closer to igniting fusion in their cores,
they generate ever more powerful stellar winds.
Eventually, the winds become strong enough to push away the surrounding material.
So the presence of bubbles typically
indicate a late-term maturing protostar.
To test this hypothesis, NIRSpec used a special
imaging mode called Integral Field Unit Spectroscopy,
and this allowed it to image the region at a set of very specific wavelengths.
They found that atomic
hydrogen, shown here in blue, is separated from the protostar.
And this is pretty much what you'd expect to see if this were entirely a bubble
that was being blown outward.
But molecular hydrogen and hydrocarbon dust shown in green and red, respectively,
are both present at all distances from the star.
In other words, there's no bubble.
The only thing that's been pushed away is the atomic hydrogen, but
that's the lightest element in the universe.
The NIRSpec images are telling us that these are not
images of a late protostar blowing out a bubble,
but rather of a much younger protostar that's still very much in its cocoon.
The curved shape of the surrounding structure is instead
being caused by the winds and radiation of the nearby stars.
In other words, this is a pillar that's slowly being eroded,
even as the fledging protostar draws the remaining matter into it.
It's this combination of sensitivity and high resolution in the infrared
that makes JWST so well-suited for studying star formation.
There's so much about how stars form.
that we just don't understand very well,
precisely because the process is hidden from view.
Now that Webb shows how well it can pierce the veil, astronomers can begin
designing future observations to better understand this process.
Although actually, Webb is already hard at work doing just that.
One of its Early release Science programs was to investigate
parts of the Orion Nebula, only 1300 light-years down the road.
Near the center of the nebula is a line of three stars
that lead to a kind of ridge called the Orion Bar.
And the ERS team released Webb's
first image of the Orion Nebula!
The bright star right next to the bar is called Theta 2 Orionis A.
It's actually a triple star system with a combined mass of about 39 Suns.
Their winds are disrupting the immediate surrounding region,
but the greater bar is largely intact.
And that's because there is a much larger cluster of stars called the Trapezium
that lies in the center of the nebula toward the northwest.
The Trapezium lies outside of NIRCam's field of view,
but they're pushing material into the bar.
So the bar is kind of like a mountain range of gas that's been
built up over time, and we just happen to be looking along its edge.
To the northeast of Theta 2 is a protostar that's still enshrouded in its cocoon
that's being eroded by the much Brighter Theta 2 star.
In the northwest is another protostar surrounded by its cocoon.
However, NIRCam lets us see through the cocoon to reveal
that the star is surrounded by a protoplanetary disk
that extends roughly out to Neptune's orbit from the Sun.
The goal of this project is to make the first ever infrared
observations of the regions where massive stars disrupt
their natal environments and dissociate the once molecular gas
and dust into hot, ionized and warm, neutral hydrogen gas.
And as is the case with all Early Released Science, NIRCam, NIRSpec, and MIRI’s
observations of Orion are being put out there into the public domain
so astronomers can revisit and figure out what kind of follow up observations
they want to make next.
Thanks to Webb, the field of astronomy is entering into a new golden age.
Okay, bad pun, but you get my point.
We now have an incredible new window into the universe.
And best of all, anyone can learn how to make sense of it.
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And as always, thanks to my patrons for helping to keep
Launch Pad Astronomy going, and I'd like to welcome my new supporter,
Logan Fredricksen, who supports me at the Galactic level.
Thank you so much, Logan.
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Until next time, stay curious, my friend.