It’s no secret that the James Webb Space Telescope has been a resounding success delivering,
so far, even better images, science and even new mysteries than was expected.
The long wait for that telescope was worth it.
And while not a comprehensive list, here are 10 interesting observations JWST has performed
so far, and what they might mean.
Number 10.
The Free Floating Brown Dwarf
On December 13, 2023 it was announced that the smallest free floating brown dwarf has
been discovered by the telescope that may call into question some models of star formation.
Located in the star cluster IC 348 at a distance of about 1000 light years in a star forming
region in the constellation perseus, this particular brown dwarf is somewhat puzzling
in that this brown dwarf is likely very young, at just 5 million years old.
The study actually found three brown dwarfs ranging from three to eight times the mass
of Jupiter.
At such a young age, the brown dwarfs are hot and bright in the infrared, Webb’s speciality.
This particular one, the smallest, however was only about three to four times the mass
of jupiter.
This is very small for that, and the group actually creates a question because they fall
within the size range of very large planets, so are they freely formed brown dwarfs or
are they ejected giant exoplanets from a star system?
This is in current debate because it can’t be ruled out, but seems unlikely due to giant
planets being rare for ejection and the cluster’s really young age hasn’t left much time for
that, so it may create more questions about star formation itself.
Mysteriously however, the observations also revealed a spectral signature of some kind
of hydrocarbon, which remains unidentified, within the atmospheres of two of the brown
dwarfs.
Number 9.
The Ringed Asteroid
Chariklo is a centaur asteroid, a class that sit in usually unstable orbits between Jupiter
and Neptune.
This particular one orbits outside Saturn’s orbit, and is fairly small at 250 kilometers.
This asteroid sports a rather interesting mystery.
It has rings, when only planets should have them.
The rings were discovered in 2013 through the occultation method, meaning that the asteroid
passes in front of a star and that allows you to do precise measurements of an object’s
position and size.
Here however, there was a double blink after the occultation had finished, indicating a
pair of rings about 400 kilometers from the asteroid’s core.
In october 2022, there was an opportunity to make the first measurement of an occultation
with Webb with the target being Chariklo, and sure enough the rings appeared again.
The JWST measurements should yield data on how thick the rings are, their color and particle
size and may even discover additional rings, but most importantly will help astronomers
try to determine just why a body this small has a ring system.
It may be that Chariklo was hit by an icy object at some point and the rings are a remnant
of that collision.
Number 8.
The Silicate Clouds of VHS 1256b
One of the areas where JWST was expected to greatly expand our knowledge is in the arena
of exoplanet atmospheres and what they contain.
A fine example of this is the exoplanet VHS 1256b.
This planet orbits a double star system about 40 light years away, but it does it very distantly
to the point that its year is equivalent to 10,000 earth years.
This actually made it a good target for Webb because of that distance, its signal doesn’t
get diluted by the direct light of the parent stars allowing for a clean spectrum.
It’s a young, hot planet, only about 150 million years old and as such has a somewhat
strange atmospheric makeup that’s in disequilibrium.
Detected were water vapor, methane, carbon monoxide and carbon dioxide.
This holds the record for the most molecules ever detected on an extrasolar planet thus
far.
But there was another.
Silicon.
This planet sports silicate clouds, basically dust on size ranges starting from the size
of a particle of smoke up to very hot small grains of sand.
The disequilibrium suggests heavy atmospheric mixing, so this is a somewhat tumultuous world.
This entry is proof of concept of what Webb can do with exoplanet atmospheres.
Number 7.
The Temperature of Trappist 1b
One of the more enticing discoveries of the last decade in exoplanet science was the discovery
of the Trappist 1 system, which has multiple planets, several of which are in the habitable
zone of the star.
These were among the prime candidates for JWST to look at to try to determine exactly
what these worlds are like.
The first on the list was the closest planet to the star in this system, Trappist 1b, which
is not in the habitable zone, rather it’s closer to the star and not a good candidate
for life.
As was expected, the observations showed Trappist 1b to have no atmosphere at all, and is very
hot at 230 degrees celsius.
This was actually the first time an exoplanet in similar circumstances to our own inner
solar system has been analyzed, and now the task will be looking at the other planets
in the system to try to get a profile of them, but that gets harder the further you get from
the star.
No guarantees, but we may soon know a lot more about this intriguing star system.
Number 6.
The Fomalhaut Asteroid Belt
The star fomalhaut is known to have a very dusty environment since it’s still relatively
young, and it’s close at just 25 light years.
Before JWST the complexities of this belt of dust was not known, but it was thought
that we might in part have been seeing an extrasolar asteroid belt, not unlike our own.
Dust glows in infrared as it absorbs light from its star and radiates it in heat, which
is what JWST as an infrared telescope is primarily designed to study.
This will be important for entry number one.
As it turns out however, the belts around fomalhaut are very different and far more
complex than those of our star system.
As it turns out, Fomalhaut has three nested asteroid belts extending out to about 23 billion
kilometers from the star.
That’s very distant in comparison to the solar system.
The belts are debris from the collision of larger accreting bodies, not unlike our own
asteroids and comets.
The outermost belt, which is enormous, had been photographed previously, but not the
two inner belts.
What’s responsible for forming or shepherding material in the disk into belts is quite simple,
it’s young unseen planets.
This happens here, Jupiter is still corralling our own asteroid belt, and Neptune does similar
for the interior edge of the Kuiper belt and there are mysteries there because something
may be shepherding its outer edge as well, in other words an undiscovered planet in the
solar system.
There’s also a further feature with Fomalhaut.
There’s an unusual dust cloud in the outer ring that might be evidence of a planetary
collision at some point in the past, which is actually the second such detection.
Hubble saw something similar in 2014 that actually seems to have dissipated.
Number 5.
The Giant Enceladus Plume
Enceladus plumes have been known for years.
What happens is that the subsurface liquid water ocean beneath its ice can escape through
cracks and spray into space from the equivalent of geysers here on earth, there known as tiger
stripes.
This is very lucky for us, in that it’s much easier to analyze a plume in space and
search for signs of life than it is to drill into an ice shell moon and see what’s there
effectively with a submarine.
But until JWST it wasn’t clear to what extent these plumes could eject water vapor.
As it turns out, it’s at least 6000 miles according to measurements by Webb, which also
reveal clues on just how Enceladus contributes to Saturn’s ring system.
It was known that Enceladus’ plumes spread material deep into space, but it wasn’t
known to what extent the actual plumes extended before dissipating, and it also revealed how
much water Enceladus is losing, which is about 79 gallons per second.
Number 4.
Organics in Deep Space
Organic chemistry is the basis of life on earth.
The vast chemistry of carbon is why we’re here, it is as far as we know the one really
good path towards life in the universe, though in fairness there are questions about silicon.
Naturally, whenever we look to the heavens for evidence of the potentials for life, we
tend to look for carbon.
But that long ago proved to be common, the stuff of life pervades the milky way and the
reason for carbon being so common are well understood.
Yet verification for other galaxies is needed.
And JWST has found a major benchmark in that search.
Observations with the telescope have shown a very distant galaxy, about 12 billion light-years
away, shows the chemistry of carbon.
Carbon was around when the universe was a mere 1.5 billion years old.
This discovery was interesting.
It was actually the signature of an Einstein ring, a very distant galaxy gravitationally
lensed by a foreground galaxy that itself was 3 billion light-years away.
The carbon compounds seen were very similar to soot or ash, and the presence of these
types of molecules in this case is a bit puzzling and hint that our ideas of organic molecule
and star formation may be too simplistic.
But that’s not the only discovery.
In an area within the milky way, known as the Orion bar of the Orion nebula, Webb was
able to see how stellar radiation erodes the bar over time leading to the creation of carbon-based
molecules and the chemistry of protoplanetary disks.
Number 3.
Carbon at Europa
Europa is alluring.
We know it has a subsurface ocean, a vast one, at temperatures where life as we know
it is comfortable.
But that’s not enough, you also need the materials that make up life.
The most basic of these is carbon.
This had been an open question regarding Europa, there was no evidence for the existence of
carbon in the ocean itself.
Carbon is a common element, there’s an entire class of meteorite that’s defined by carbon
and those fall everywhere in the solar system, so it’s not surprising to have found it,
but recent JWST observations have proven that there is carbon at Europa.
The measurement was from an area of Europa’s surface known as Tara Regio and comes in the
form of carbon dioxide deposits.
Moreover, they were able to determine that this CO2 is very likely to have originated
in the ocean below, rather than having been delivered by meteorites.
And it’s recent, carbon dioxide is not stable on the surface of Europa over long periods.
Oddly however, previous evidence for plumes of water vapor escaping cracks in the surface
of Europa similarly to Enceladus were not confirmed by the Webb observations suggesting
that plume activity may be intermittent at Europa.
But we won’t have to wait long for more information, two missions are set to explore
Europa in depth, one being the Jupiter Icy Moons explorer which is already launched and
set to arrive in the Jovian system in 2031, and the Europa Clipper mission is set to launch
on a falcon heavy in late 2024 and arrive in 2030.
Number 2.
The Atmospheres of WASP Worlds
The Wide Angle Search for Planets, or WASP is an effort in exoplanet detection that has
discovered well over 100 exoplanets.
Once discovered, these exoplanets, if they are suitable, can become prime targets of
Webb.
The first of three examples would be the hot jupiter WASP 17b.
Located about 1300 light-years away, this giant planet orbits its star verily closely,
and oddly in a retrograde orbit.
This planet too was found by Webb to have silicates in its atmosphere in the form of
quartz nanocrystals.
Interestingly, this planet is so hot that it’s possible for nanocrystals to form directly
from it’s constituent elements from gas, bypassing a liquid stage.
The second is WASP 107b.
This exoplanet has a mass comparable to Neptune, but a diameter approaching Jupiter, in short,
it’s puffy.
This actually eases the challenges of peering deep into this exoplanet, even more so than
for solar system gas giants.
Water vapor, sulfur dioxide and more silicate clouds were found, but no methane.
That provides a unique study of how heat works and traps on this exoplanet.
In contrast is the third, WASP 80b, where methane was definitely found.
This one is a warm Jupiter, with a size and mass comparable to Jupiter itself.
At 163 light-years away, this exoplanet shows a different temperature profile than our gas
giants, and also sports detectable methane.
This will probably be a repeated object for Webb to observe, due to the unique circumstances
in that it may allow us the biggest bang for the buck in studying a gas giant atmosphere
outside the solar system.
Number 1.
KIC 8462852
One of the most enigmatic discoveries in recent years was KIC 8462852 or Tabby’s star.
The behavior of this star has defied explanation to the point that the activities of an alien
civilization are still on the table, though not as strongly as when the story first broke.
The star’s periodic mysterious dimming continues, and it still defies explanation.
Whatever is blocking the light from the star is consistent with submicron dust, but it
does not appear to be in a periodic orbit of the star.
One enigma however is that an observation in infrared showed that whatever the material
is, it must be cold because it was not detectable in infrared, leading to hypotheses about cold
comets breaking up, but that would require an implausibly large number of comets in the
system to account for it.
One of the more common questions I get in the comments section here and at Event Horizon
is will JWST turn its eye on Tabby’s star and take an observation?
The answer is yes.
And it’s already happened.
Last summer between June and August JWST took a series of three spaced out images of the
star in infrared at a much higher resolution than the previous measurement.
The scientists involved have not yet released their findings, but it’s possible that it
might settle the question and pick up the missing infrared emissions.
What will be interesting however is if it comes up null again.
Given the curveballs the star has given us at every turn, it wouldn’t surprise me if
the mystery deepens with the Webb observations.
Thanks for listening!
I am futurist and science fiction author John Michael Godier currently looking forward to
a new year of JWST observations, imagine what we’ll see, but also first light of the Vera
Rubin observatory which is set to be a mystery factory as it picks up everything from asteroids,
potential undiscovered outer solar system planets and even interstellar object cooking
through.
It’s going to be good and be sure to check out my books at your favorite online book
retailer and subscribe to my channels for regular, in-depth explorations into the interesting,
weird and unknown aspects of this amazing universe in which we live.