Speaker 1: Welcome to Bedtime Astronomy. Explore the wonders of the cosmos
Speaker 1: with our soothing Bedtime Astronomie podcast. Each episode offers a
Speaker 1: gentle journey through the stars, planets, and beyond, perfect for
Speaker 1: unwinding after a long day. Let's travel through the mysteries
Speaker 1: of the universe as you drift off into a peaceful
Speaker 1: slumber under the night sky.
Speaker 2: I want you to take a second and just imagine
Speaker 2: looking through a viewing portal, but you're not looking at
Speaker 2: the universe as it is today. You are watching a
Speaker 2: mirror image of our very own solar system, but at
Speaker 2: the exact moment of its like chaotic, violent birth. You're
Speaker 2: not seeing Earth and Mars and Jupiter all neatly sorted
Speaker 2: into their stable orbits. You were watching this swirling, turbulent
Speaker 2: delivery room of a cosmic neighborhood. And the craziest part
Speaker 2: is you are watching it actively unfold right this second.
Speaker 3: Yeah, and for the vast majority of astronomical history, trying
Speaker 3: to understand how planets formed was basically an exercise in forensics, right,
Speaker 3: like a crime scene exactly. I mean, we had our
Speaker 3: own mature solar system to study, and we were essentially
Speaker 3: just investigating the aftermath of a massive.
Speaker 2: Explosion, just looking at the debris.
Speaker 3: Right, we had to look at this coal debris, you know,
Speaker 3: the current orbits of the planets, the makeup of asteroids,
Speaker 3: where the comets are distributed. And from that we had
Speaker 3: to try and reverse engineer the exact placement and like
Speaker 3: the yield of the original dynamite.
Speaker 2: Which sounds impossible, it's incredibly difficult.
Speaker 3: I mean, we had theoretical physics models running on supercomputers, sure,
Speaker 3: but we lacked the direct observational evidence of the process
Speaker 3: actually occurring. But now, well, the paradigm has completely shifted.
Speaker 3: What's fascinating here is we are transitioning from guessing how
Speaker 3: planets form to actively watching it happen. We basically have
Speaker 3: a camera recording the blast.
Speaker 2: Okay, let's unpack this, because that shift is exactly what
Speaker 2: makes late more Arch of twenty twenty six such a
Speaker 2: landmark moment for astronomy.
Speaker 3: Oh.
Speaker 2: Absolutely, Telescopes pointed at the constellation Aquila, which is about
Speaker 2: four hundred and thirty seven light years away, have captured
Speaker 2: the most detailed, structurally complex view we have ever seen
Speaker 2: of a new solar system forming. It's stune in and
Speaker 2: the anchor of this whole system is a baby star.
Speaker 2: They needed it, whisp it too, right, And surrounding it
Speaker 2: is this colossal disk of gas and dust. Embedded in
Speaker 2: that disk are two confirmed heavyweight planets, and they are
Speaker 2: actively gorging on material and carving out their orbits, which.
Speaker 3: Is just wild to see in real time, it really is.
Speaker 2: So our objective today is to explore exactly how those
Speaker 2: chaotic clouds of dust actually transform into structured worlds. We're
Speaker 2: going to look at what these newly discovered giant baby
Speaker 2: planets look like, and how this five million year old
Speaker 2: star holds the secrets to our own four point six
Speaker 2: billion year history.
Speaker 3: Yeah, the transition from theoretical modeling to direct observation, it
Speaker 3: really just cannot be overset.
Speaker 2: Here because it used to just be math on a chalkboard.
Speaker 3: Exactly for decades. The intricate mechanisms of planetary accretion. You know,
Speaker 3: how microscopic dust grains overcome electrostatic barriers, how they stick
Speaker 3: together to grow into pebbles and then planetesimals and eventually
Speaker 3: into massive gas giants. All of that mostly lived in
Speaker 3: fluid dynamics equations and magnetohydrodynamic simulation, which is a mouthful,
Speaker 3: it is, but basically we knew the math worked. The
Speaker 3: problem was ground shooth verification was really scarce.
Speaker 2: We could just go out and take a picture of it, right.
Speaker 3: But whisp It two offers us this multiplanet laboratory where
Speaker 3: we can finally test those models against reality. We can
Speaker 3: measure the exact mass, the temperature, the orbital kinematics of
Speaker 3: these planets as they are actively being forged.
Speaker 2: Okay, so let's start with the anchor of the whole thing,
Speaker 2: the star itself, whisp It too. Okay, it's characterized as
Speaker 2: a pre main sequence star and it's roughly five million
Speaker 2: years old. Now to you and me, five million years
Speaker 2: sounds ancient, right sure, But against the four point six
Speaker 2: billion year age of our own Sun, whisp of two
Speaker 2: is basically a newborn, very much so. But the metric
Speaker 2: that really caught my eyes it's mass. It's clocked at
Speaker 2: one point zero eight solar masses.
Speaker 3: Yeah, that's the crucial number.
Speaker 2: Because it makes it a near perfect analog for what
Speaker 2: our Sun looked like when it was a baby. It's
Speaker 2: essentially a twin exactly.
Speaker 3: It's that one point arrow eight solar mass metric. That
Speaker 3: makes it so valuable because its composition and size mirror
Speaker 3: our Sun. The surrounding protoplanetary disk that's swirling reservoir of
Speaker 3: leftover gas and dust is the perfect proxy for the
Speaker 3: primordial soup that build Earth.
Speaker 2: Right, But you mentioned it's a pre main sequence star,
Speaker 2: meaning it hasn't turned on yet.
Speaker 3: Basically, yes, it hasn't achieved the internal pressure and temperature
Speaker 3: required to ignite sustained hydrogen fusion in its core.
Speaker 2: So if wisp it iiO hasn't turned on as core
Speaker 2: hydrogen fusion yet, where's the thermal budget coming from? Like
Speaker 2: is the surrounding material colder or is the violence of
Speaker 2: gravity providing the heat? How is it generating enough energy
Speaker 2: to keep the disc from just freezing into solid ice?
Speaker 3: That is a great question, and it goes straight to
Speaker 3: the thermodynamics of how stars are born. Okay, while wispit
Speaker 3: two lacks that sustained hydrogen fusion, it's driven by something
Speaker 3: we call the Kelvin Helmholtz mechanism.
Speaker 2: The Kelvin Helmholtz mechanism, got it, What is that?
Speaker 3: So the star is still in the process of gravitational collapse.
Speaker 3: It formed from a vast cold molecular cloud, and as
Speaker 3: that immense volume of gas falls inward on itself, gravitational
Speaker 3: potential energy gets converted into kinetic.
Speaker 2: Energy because it's moving faster, exactly.
Speaker 3: And as those gas particles compress and collide at higher
Speaker 3: and higher velocities, that kinetic energy is converted into thermal energy.
Speaker 2: So it's essentially heating up because it's crushing itself.
Speaker 3: That is exactly the mechanism. It's glowing purely from the
Speaker 3: intense friction and pressure of its own gravitational contraction.
Speaker 2: Wow.
Speaker 3: Yeah, And according to the viurial theorem, about half of
Speaker 3: the gravitational potential energy released during this collapse radiates away
Speaker 3: as starlight and the other half remains trapped inside and
Speaker 3: it steadily raises the coret temperature. Eventually, millions of years
Speaker 3: from now, that core temperature will hit roughly fifteen million.
Speaker 2: Kelvin, which is when it finally turns on.
Speaker 3: Right, that's what's required to sustain hydrogen fusion, and whisp
Speaker 3: bit two will officially join the main sequence. But right now,
Speaker 3: the fact that it hasn't ignited fusion is huge.
Speaker 2: Why is that so important for the planets?
Speaker 3: Because it hasn't generated the intense sustained stellar winds yet
Speaker 3: that outward radiation pressure that eventually blows all the primordial
Speaker 3: planet making material out of the system. Oh I see, Yeah,
Speaker 3: So the protoplanetary disk around wispit two is still dense,
Speaker 3: it's rich, and it's undisturbed, so.
Speaker 2: It's prime real estate for building planets exactly. Now. I
Speaker 2: know this isn't the absolute first time we've caught a
Speaker 2: system in this phase. Back in twenty eighteen, there was
Speaker 2: the discovery of PDS.
Speaker 3: Seventy, Yes, a very famous system.
Speaker 2: Right, it's about three hundred and seventy light years away,
Speaker 2: and astronomers found two forming protoplanets there. That was the
Speaker 2: first proof that we could actually witness planetary birth. But
Speaker 2: when I was looking into this, it seems like PDS
Speaker 2: seventy is treated as a proof of concept, whereas wispit
Speaker 2: two is being treated as this comprehensive laboratory.
Speaker 3: That's a very fair assessment.
Speaker 2: I kind of think of PDS seventy as like finding
Speaker 2: a single blurry polaroid of a baby, huh, whereas whispit
Speaker 2: two is like finding an entire high definition home video
Speaker 2: with a wider cast of characters. But what specific data
Speaker 2: does whispit two provide that fundamentally elevates our understanding compared
Speaker 2: to PDS seventy.
Speaker 3: Well, PDS seventy was a watershed moment for sure. It
Speaker 3: gave us the first unambiguous direct images of protoplanets PDS
Speaker 3: seventy B and C sitting inside a transition disc. Right,
Speaker 3: we could measure their hydrogen alpha emission, which is basically
Speaker 3: a specific wavelength of light that acts as a direct
Speaker 3: tracer of hot hydrogen gas accreting onto the planets.
Speaker 2: So it proved that planets were actually gathering material.
Speaker 3: Yes, it proved the accretion models were fundamentally correct. However,
Speaker 3: PDS seventy had limitations when it came to visibility of
Speaker 3: the discs structure itself, like.
Speaker 2: The environment around the planets.
Speaker 3: Exactly the gaps were there, but the extended complex architecture
Speaker 3: wasn't as cleanly defined.
Speaker 2: So it was essentially just a narrow window into the process.
Speaker 3: Yes, whispit two, by contrast, has an extraordinarily extended disc.
Speaker 3: It has multiple highly distinct concentric rings and these deeply
Speaker 3: carved gaps that are clean enough to measure precise kinematic.
Speaker 2: Deviations, meaning we can see how things are moving.
Speaker 3: We aren't just seeing the planets glowing. We can measure
Speaker 3: the exact velocity field of the gas flowing around them.
Speaker 3: We can map the surface density gradients of the dust. Wow,
Speaker 3: Whispit too allows us to observe not just the existence
Speaker 3: of the planets, but the real time fluid dynamics of
Speaker 3: the environment they are manipulating.
Speaker 2: Okay, so let's talk about the planets too in the manipulating,
Speaker 2: because the scale of these bodies is just staggering.
Speaker 3: They are massive, right.
Speaker 2: The first one confirmed, Whispit two B, was directly imaged
Speaker 2: in twenty twenty five. This is a gas giant with
Speaker 2: a mass roughly four point nine times that of Jupiter,
Speaker 2: and its orbital location is way out in the deep
Speaker 2: frieze of the system. It's sitting at a distance of
Speaker 2: fifty seven to sixty astronomical units from the host star.
Speaker 2: And for context for you listening, Neptune sits at thirty AU.
Speaker 2: So Whispit two B is orbiting at twice the distance
Speaker 2: of the furthest major planet in our own Solar system.
Speaker 3: Yeah, and a four point nine juper mass object at
Speaker 3: sixty AU poses a significant challenge to our standard formation models,
Speaker 3: which we can get into later.
Speaker 2: Right, but physically what is it doing out there?
Speaker 3: Well, regarding its physical state, Whispit two B is currently
Speaker 3: operating as a massive gravitational sink. Okay, at sixty AU.
Speaker 3: The orbital period is vast, meaning the planet takes hundreds
Speaker 3: of years to complete a single revolution around the star.
Speaker 2: Just one year for that planet is centuries for us exactly.
Speaker 3: And as it slowly plows through the outer disc, it
Speaker 3: is accreting gas and dust within its hill sphere.
Speaker 2: It's hillsphere.
Speaker 3: Yeah, the hill sphere is the region where the planet's
Speaker 3: gravity dominates over the gravitational pull of the host star.
Speaker 2: Oh so anything that enters that sphere is basically getting
Speaker 2: sucked in pretty much. And that accretion process itself is
Speaker 2: generating a massive amount of in red radiation. Correct, Yeah,
Speaker 2: I mean the heat isn't just coming from the star,
Speaker 2: It's coming from these colossal, glowing babies hidden in the dust.
Speaker 2: The material isn't just gently falling onto the planet, it's
Speaker 2: slamming into it.
Speaker 3: Yes, the physics of accretion are incredibly violent.
Speaker 2: How violent are we talking? Well?
Speaker 3: Gas falling toward the planet accelerates to supersonic speeds.
Speaker 2: Wow.
Speaker 3: And when it finally strikes the denser atmosphere or the
Speaker 3: surface of the growing proto planet, it creates an accretion shock.
Speaker 2: Oh man.
Speaker 3: The kinetic energy of that in falling gas is instantaneously
Speaker 3: converted into heat. It raises the local temperature to thousands.
Speaker 2: Of degrees, So even out in the deep freeze, it's
Speaker 2: scorching hot.
Speaker 3: Exactly. That is why a planet out at sixty AU,
Speaker 3: a region where the ambient temperature of the disk is
Speaker 3: barely above absolute zero, is glowing brightly enough in the
Speaker 3: near for red spectrum to be detected four hundred and
Speaker 3: thirty seven light years away, because.
Speaker 2: It's radiating its own formation. Here. Yes, okay, so that's
Speaker 2: the outer planet. But that brings us to the March
Speaker 2: twenty twenty six data which confirmed the second planet Wispit
Speaker 2: to C. And here is where it gets really interesting.
Speaker 2: The architecture of this system becomes highly counterintuitive. It does
Speaker 2: Whispit two c orbits much closer to the star at
Speaker 2: roughly fourteen AU, yet it is estimated to be between
Speaker 2: eight and twelve jupiter masses. It is roughly twice as
Speaker 2: massive as the outer planet.
Speaker 3: Yes, it's a heavyweight.
Speaker 2: But confirming this required spectroscopic data, specifically looking for carbon monoxide,
Speaker 2: walking through the physics of that detection. Because finding something
Speaker 2: at fourteen AU seems way harder than finding something at
Speaker 2: sixty AU.
Speaker 3: It is significantly harder. Confirming wispit two C was a
Speaker 3: huge triumph of high resolution spectroscopy.
Speaker 2: Why is it so difficult.
Speaker 3: Because at fourteen au the angular separation between the planet
Speaker 3: and the star is incredibly tight. The glare of WISPIT
Speaker 3: two is overwhelming.
Speaker 2: It's just blinding that telescope, right.
Speaker 3: So to prove that this faint point of light wasn't
Speaker 3: just a background artifact or like a localized clump of
Speaker 3: hot dust, astronomers utilized integral field spectrographs. Okay, they needed
Speaker 3: to analyze the specific wavelengths of light being emitted. They
Speaker 3: targeted the K band in the near infrared, and specifically
Speaker 3: they were looking for the row vibrational absorption bands of
Speaker 3: carbon monoxide, which occur around two point three microns.
Speaker 2: Wait, why carbon monoxide that? Why not look for hydrogen
Speaker 2: or methane.
Speaker 3: That's a good point. So carbon monoxide is an exceptionally
Speaker 3: stable molecule and it's a dominant carbon bearing species in
Speaker 3: the hot, high pressure environments of forming gas giant atmospheres.
Speaker 2: Oh okay, so it survives the heat exactly.
Speaker 3: Methane, on the other hand, requires much cooler temperatures to
Speaker 3: remain stable in large quantities and hydrogen. Hydrogen is abundant, sure,
Speaker 3: but its emission lines can often be confused with stellar
Speaker 3: activity or just general accretion flows in the broader disk.
Speaker 2: So it's not specific.
Speaker 3: Enough, right, But the specific roe Vibe rational signature of
Speaker 3: carbon monoxide acts as an unequivocal chemical fingerprint for a
Speaker 3: dense planetary mass atmosphere.
Speaker 2: It's the smoking gun exactly. But finding the molecule isn't
Speaker 2: enough on its own, is it. I mean you have
Speaker 2: to prove it actually belongs to something orbiting the star
Speaker 2: and not just gas floating around.
Speaker 3: Yes, and that is where the kinematics come into play
Speaker 3: the movement right By observing the K band spectrum with
Speaker 3: incredibly high spectral resolution, astronomers can measure the Doppler shift
Speaker 3: of those carbon monoxide.
Speaker 2: Lines, like how a siren sounds different when an ambulance
Speaker 2: drives past you.
Speaker 3: Exactly like that, but with light as the planet orbits
Speaker 3: the star, its velocity relative to our telescopes on Earth changes.
Speaker 3: When it moves slightly toward us in its orbit, the
Speaker 3: Kban lines.
Speaker 2: Blue shift, and when it moves away a red shift.
Speaker 3: So by measuring this precise shift, astronomers can calculate the
Speaker 3: Keplarian velocity of the object the actual speed of its orbit. Yes,
Speaker 3: and the data showed that this glowing source of carbon
Speaker 3: monoxide was moving at the exact velocity required for an
Speaker 3: object in a stable bound orbit at fourteen AU.
Speaker 2: So it couldn't just be random gas.
Speaker 3: No, it was definitive proof of a massive eight to
Speaker 3: twelve jupiter mass planet.
Speaker 2: Okay, I see the logic in the detection, but the
Speaker 2: mass distribution still seems completely backward to me. How so, Well,
Speaker 2: Whispit two C is at fourteen AU, Whispit two B
Speaker 2: is at sixty AU. The circumference of an orbit at
Speaker 2: sixty AU is vastly larger, Right, Yes, it is so
Speaker 2: the outer planet has a much longer track to run,
Speaker 2: meaning as a much wider volume of space to sweep through.
Speaker 2: Given that, why is the inner baby so much hungrier?
Speaker 2: Shouldn't the planet further out have more room to sweep
Speaker 2: up material and get bigger.
Speaker 3: I get why you'd think that. It's a very common
Speaker 3: misconception to equate orbital circumference with available mass.
Speaker 2: Oh really yeah.
Speaker 3: In a protoplanetary disk, we have to look at the
Speaker 3: radial service density profile. The material, the gas, and the
Speaker 3: dust is not distributed even.
Speaker 2: Lanth It's not just a flat, uniform sheet, right.
Speaker 3: The disc is governed by fluid dynamics, and typically the
Speaker 3: surface density is highest near the star and falls off
Speaker 3: extonentially as you move outward.
Speaker 2: Ah. So the raw material is just thicker on the
Speaker 2: inside track.
Speaker 3: Thicker by orders of magnitude.
Speaker 2: Wow.
Speaker 3: To use a mechanical analogy, imagine driving a snowplow. Right,
Speaker 3: the outer planet at sixty AU is driving a massive
Speaker 3: sweeping route across a giant parking lot, but the parking
Speaker 3: lot only has a sparse half inch dusting of snow. Right,
Speaker 3: the inner planet at fourteen AU has a much shorter route,
Speaker 3: but it is driving through drifts that are ten feet high.
Speaker 2: Okay, that makes perfect sense. That tracks completely. But is
Speaker 2: it just a static distribution of density or is material
Speaker 2: actively moving toward the inner planet.
Speaker 3: It is highly dynamic. We have to consider radial drift,
Speaker 3: particularly for the pebble size solid particles in the.
Speaker 2: Disc radial drifts. So things are migrating.
Speaker 3: Yes, in the disc, the gas is partially supported by
Speaker 3: outward thermal pressure, meaning the gas actually orbit slightly slower
Speaker 3: than the cuplarian velocity.
Speaker 2: Slower than a purely gravitational orbit.
Speaker 3: Right, But the solid pebbles they don't feel that gas pressure.
Speaker 3: They want to orbit at the faster full caplarian velocity.
Speaker 2: Wait, so the pebbles are trying to go fast, but
Speaker 2: the gas is going slow exactly, meaning the pebbles are
Speaker 2: constantly fighting a headwind from the slower moving gas.
Speaker 3: That's the perfect way to visualize it, and that headwind
Speaker 3: acts as aerodynamic drag. Ah okay, it bleeds orbital angular
Speaker 3: momentum from the pebbles, which causes them to constantly spiral
Speaker 3: inward toward the star.
Speaker 2: Oh wow.
Speaker 3: So not only is wispit to see sitting in an
Speaker 3: inherently denser region of the disk to begin with, it
Speaker 3: is positioned in a cosmic bottleneck, a bottlenic right, where
Speaker 3: vast quantities of solid material from the outer discs are
Speaker 3: continually drifting inward, delivering an endless supply of mass right
Speaker 3: to the inner planet's feeding zone.
Speaker 2: So it's basically sitting at the end of a buffet
Speaker 2: line exactly.
Speaker 3: Whispit to C is gorging itself on this inward migration,
Speaker 3: and that allows it to rapidly balloon to ten times
Speaker 3: Jupiter's mass.
Speaker 2: Well, the outer planet is starving.
Speaker 3: Well, Whispit two B is forced to accrete from the
Speaker 3: much sparser depleted material out in the outer disc. So yes,
Speaker 3: it grows much slower.
Speaker 2: That aerodynamic drag mechanism completely changes how I view the disc.
Speaker 2: It's not a static ring. It's a conveyor belt. It
Speaker 2: absolutely is, and the planets are actively disrupting that conveyor belt,
Speaker 2: which naturally brings us to the visual architecture of the
Speaker 2: Wispit two disc. We talked about how we're seeing these
Speaker 2: visible scars these planets are leaving behind. We see these massive, bright,
Speaker 2: concentric rings of dust separated by deep, dark gaps. Right
Speaker 2: if we picture a giant vinyl record, the dust makes
Speaker 2: up the ridges, and the planets are the needles carving
Speaker 2: out the grooves, pulling in mass as gravity takes over.
Speaker 2: But how exactly does a planet's gravity physically clear a
Speaker 2: gap that is billions of miles wide. I mean, it
Speaker 2: can't possibly accrete all that material, can it?
Speaker 3: Oh? No, it doesn't accrete all of it. In fact,
Speaker 3: it it cretes relatively small fraction.
Speaker 2: So where does the rest of it go?
Speaker 3: The vast majority of the material is pushed away through
Speaker 3: gravitational torques.
Speaker 2: Yes.
Speaker 3: When a massive planet like Wisp it two B or
Speaker 3: two C orbits within a gaseous disc, it interacts gravitationally
Speaker 3: with the surrounding material and it launches spiral density waves.
Speaker 2: Spiral density waves, that sounds intense.
Speaker 3: They are. These waves are very similar to the wake
Speaker 3: created by a boat moving through water. As these density
Speaker 3: waves propagate away from the planet, both inward toward the
Speaker 3: star and outward into the deeper disc, they eventually shock
Speaker 3: the gas.
Speaker 2: They shock it, meaning they compress it and transfer momentum.
Speaker 3: Yes, the waves deposit angular momentum into the outer disc,
Speaker 3: which physically pushes the gas further away from the star.
Speaker 2: Oh okay.
Speaker 3: And conversely, they extract angular momentum from the inner disc,
Speaker 3: causing that gas to fall closer to the star.
Speaker 2: This is pushing material in both directions away from its
Speaker 2: orbit exactly.
Speaker 3: The net result is that the gas is actively repelled
Speaker 3: from the planet's orbit, creating a cleared region or a
Speaker 3: gar app.
Speaker 2: But the images we are seeing from the telescopes are
Speaker 2: primarily showing dust, not just gas, right, correct, So how
Speaker 2: does pushing the gas away create those incredibly sharp bright
Speaker 2: rings of dust on either side of the gap? Ah?
Speaker 3: This ties directly back to the aerodynamic.
Speaker 2: Drag we just discussed the headwinds. Right.
Speaker 3: When the planet pushes the gas away and creates a gap,
Speaker 3: it creates a localized pressure gradient at the edge.
Speaker 2: Of that gap, meaning the gas pressure spikes.
Speaker 3: Yes, the gas pressure increases sharply just outside the cleared zone. Now,
Speaker 3: remember that solid pebbles drift inward due to the.
Speaker 2: Gas headwind, right the spiraling in.
Speaker 3: But when those inward drifting pebbles hit that sudden spike
Speaker 3: in gas pressure at the outer edge of the gap,
Speaker 3: the headwind disappears. Oh, the pressure bump acts as an
Speaker 3: aerodynamic trap.
Speaker 2: So they just stop.
Speaker 3: The pebble stop drifting inward, and they pile up massively
Speaker 3: at the edge of the gap.
Speaker 2: So the planet is essentially building a dam.
Speaker 3: It is building a dam, and the bright rings we
Speaker 3: see and the telescope image are the reservoirs of dust
Speaker 3: trapped behind that dam.
Speaker 2: That is incredible.
Speaker 3: The gap itself is largely cleared of both gas and
Speaker 3: millimeter sized dust, making it look dark, while the edges
Speaker 3: glow brilliantly because of the concentrated dust accumulation.
Speaker 2: Okay, let me stop you there, though. If I'm playing
Speaker 2: Devil's advocate here, Okay, how do we know for sure
Speaker 2: that a dark gap equals a planet? Couldn't the gap
Speaker 2: be caused by something else? Like what, well, what if
Speaker 2: it's a snow line, like a region where a specific
Speaker 2: gas like carbon monoxide suddenly freezes into a solid, changing
Speaker 2: the opacity of the disk and just making it look
Speaker 2: like a gap? Or what about magnetic dead zones where
Speaker 2: turbulence drops off.
Speaker 3: That is a crucial distinction, and honestly, it's a major
Speaker 3: debate in planetary science all right. For years, when we
Speaker 3: only had lower resolution imagery, alternative theories like snow lines
Speaker 3: or magnetor rotational instability variations were highly viable explanations for disc.
Speaker 2: Gaps because we couldn't prove otherwise exactly.
Speaker 3: However, wisp it too provides the kinematic data to rule
Speaker 3: those out. Wow, Well, a snow line changes the chemical
Speaker 3: state of the disk, but it does not drastically alter
Speaker 3: the velocity of the gas flow. A massive planet, however,
Speaker 3: does By using high resolution spectroscopy, astronomers mapped the caplearian
Speaker 3: velocity of the carbon monoxide gas inside and around the gaps,
Speaker 3: and they found localized distinct deviations in the gas velocity,
Speaker 3: tiny twists or kinks in the kinematic map.
Speaker 2: Like the gas is swerving. Yes, so the gas is
Speaker 2: literally flowing around the gravitational well of the planet.
Speaker 3: Precisely. Those kinematic twists are the undeniable dynamic signatures of
Speaker 3: a massive, localized gravitational body. They prove we aren't just
Speaker 3: looking at a chemical illusion or a shadow.
Speaker 2: We are looking at the gravitational fingerprint of.
Speaker 3: A planet exactly. We don't necessarily have to see the
Speaker 3: planet to know it's there. Gravity leaves a fingerprint, and
Speaker 3: this fingerprint analysis is leading to even more discoveries in
Speaker 3: the wispit too system.
Speaker 2: We really there's more.
Speaker 3: Oh yeah, Beyond the massive gaps carved by two B
Speaker 3: and T who see, researchers have identified a third, much
Speaker 3: narrower and shallower gap further out in the disc and.
Speaker 2: The assumption is that this is a third planet just smaller.
Speaker 3: Exactly, the depth and width of a gap are directly
Speaker 3: proportional to the mass of the planet, carding it balanced
Speaker 3: against the viscosity of the disk trying to refill it.
Speaker 2: So what does the math say about this third one?
Speaker 3: The math suggests this third gap is being maintained by
Speaker 3: a planet roughly the mass of Saturn.
Speaker 2: A Saturn sized baby.
Speaker 3: Right, it is currently too low mass and therefore not
Speaker 3: generating enough accretion heat to be directly imaged by our current.
Speaker 2: Instruments, But the fingerprint is there.
Speaker 3: The dynamic signature is there. As Chloe Lawler, she's a
Speaker 3: PhD student at the University of Galway, she pointed out
Speaker 3: that this multi gap architecture strongly implies an entire planetary
Speaker 3: system is sequentially forming. The structure itself is a historical
Speaker 3: ledger of the system's evolution. She said, It's basically the
Speaker 3: best look into our own past that we have to date.
Speaker 2: That is just wild to think about, and it leads
Speaker 2: per into the technological reality of this discovery. I mean,
Speaker 2: I marvel at the fact that we can see a
Speaker 2: fingerprint four hundred and thirty seven light years away. We
Speaker 2: are analyzing the kinematic twists in gas flows and the
Speaker 2: thermal radiation of planetary accretion, all while fighting the blinding
Speaker 2: glare of the host star.
Speaker 3: It's a monumental engineering feed.
Speaker 2: The analogy I usually hear for this is trying to
Speaker 2: photograph a single firefly sitting next to a lighthouse from
Speaker 2: thousands of miles away.
Speaker 3: That's the classic one.
Speaker 2: Yeah, but given the physics of the cave in infrared
Speaker 2: and the adaptive optics involved, I feel like a better
Speaker 2: analogy is trying to detect the specific thermal signature of
Speaker 2: a single lit match sitting on the rim of an
Speaker 2: industrial blast furnace from thirty miles away through a torrential downpour.
Speaker 3: Huh.
Speaker 2: That is remarkably accurate, right, So how are the telescopes
Speaker 2: physically filtering out the blast furnace to see the match
Speaker 2: break down? The paparazzi gear for us?
Speaker 3: Okay, Well, the torrential downpour in your analogy represents Earth's atmosphere.
Speaker 2: Okay.
Speaker 3: Even on the highest dry peeps of the Atacama Desert
Speaker 3: in Chile, where the European Southern Observatory's very large telescope,
Speaker 3: the VLT is located, the atmosphere.
Speaker 2: Is turbulent, the air is always moving.
Speaker 3: Right, packets of air at varying temperatures act like thousands
Speaker 3: of tiny moving lenses. They are continuously refracting and distorting
Speaker 3: the incoming.
Speaker 2: Starlight, which is why stars twinkle.
Speaker 3: Exactly if you take a standard long exposure photograph, that
Speaker 3: turbulence smears the light of the star into a massive,
Speaker 3: fuzzy halo that completely engulfs any faint planets.
Speaker 2: So the first step is basically removing the atmosphere. How
Speaker 2: does VLT achieve that without actually going into space.
Speaker 3: Through advanced adaptive optics, primarily using an instrument.
Speaker 2: Called sphere sphere What does that do?
Speaker 3: Sphere relies on a shack Hartman wavefront sensor and a
Speaker 3: deformable mirror.
Speaker 2: The deformable mirror like it changes.
Speaker 3: Shape, Yes, literally, the telescope analyzes the incoming light from
Speaker 3: wisp it to the wavefront sensor, splits the telescope's pupil
Speaker 3: into thousands of sub apertures, and it measures exactly how
Speaker 3: the wavefront of the light has been warped by the
Speaker 3: atmosphere at that exact microsecond.
Speaker 2: So take a reading of the distortion.
Speaker 3: Right, and then it mechanically corrects it in real time.
Speaker 2: How fast is real time?
Speaker 3: It sends that data to a computer, which calculates the
Speaker 3: inverse of that distortion. The computer then sends electrical signals
Speaker 3: to thousands of microscopic actuators located behind a thin, flexible mirror.
Speaker 2: Wow.
Speaker 3: Those actuators push and pull the mirror, physically deforming its
Speaker 3: shape to exactly cancel out the atmosphereic turbulence. And it
Speaker 3: does this at a frequency of over a thousand times
Speaker 3: per second.
Speaker 2: A thousand times a second. That's unbelievable.
Speaker 3: It's incredible technology. It essentially flattens the wavefront, effectively removing
Speaker 3: the Earth's atmosphere and turning the blurry halo back into
Speaker 3: a sharp single point of starlight.
Speaker 2: Okay, but the star is still a blast furnace. You
Speaker 2: have a sharp point of light now, but it's still
Speaker 2: millions of times brighter than the planet. How do you
Speaker 2: block it?
Speaker 3: Once the light is corrected by the adaptive op it
Speaker 3: is fed into a coronagraph.
Speaker 2: A coronagraph, right at.
Speaker 3: Its most basic level, a coronograph is a highly engineered
Speaker 3: physical mask placed exactly at the focal plane of the paliscope.
Speaker 3: It functions as an artificial eclipse physically blocking the core
Speaker 3: light of the star.
Speaker 2: Oh clever, So you just put a dot over the
Speaker 2: bright part.
Speaker 3: Basically, yes. However, because light acts as a wave, simply
Speaker 3: blocking the center isn't enough. The starlight diffracts, It bends
Speaker 3: around the edges of the mask and creates bright, concentric
Speaker 3: rings that would still blind the sensors.
Speaker 2: So the light leaks around the edge exactly.
Speaker 3: But modern coronagraphs, like the appetized pupil leot coronographs used
Speaker 3: on Sphere utilize secondary masks and complex optical shapes to
Speaker 3: actively suppress those diffraction rings. Oh wow, this allows the
Speaker 3: faint infrared glow of the disc and the outer planet
Speaker 3: whisp It to be, to finally emerge from the darkness.
Speaker 2: Okay, so that covers Sphere and the discovery of the
Speaker 2: outer planet. But whisp it to see is at fourteen A.
Speaker 2: It's incredibly close to the star.
Speaker 3: A coronagraph alone isn't enough to resolve something that tight,
Speaker 3: is it?
Speaker 2: No? It is not. At fourteen AU, the angular separation
Speaker 2: is below the diffraction limit of a single eight meter
Speaker 2: mirror on the VLT.
Speaker 3: Meaning the mirror just isn't big enough to see it exactly.
Speaker 2: The resolving power of a telescope is fundamentally limited by
Speaker 2: the diameter of its primary mirror. To see something as
Speaker 2: tight as wisp it to see, you would need a
Speaker 2: mirror over one hundred meters wide, which of course doesn't exist.
Speaker 3: So what did they do?
Speaker 2: This is where the technological leap of the VLTI, the
Speaker 2: very large Telescope interferometer and the gravity plus instrument becomes
Speaker 2: the hero of the story.
Speaker 3: Interferometr that's essentially combining multiple telescopes to act as one
Speaker 3: giant one.
Speaker 2: Right, But how do you combine the light without losing
Speaker 2: the phase data? I imagine it's super delicate.
Speaker 3: That is the supreme engineering challenge. The VLTI takes the
Speaker 3: light collected from all four of the eight meter unit
Speaker 3: telescopes on the mountain. Okay, by combining that light, they
Speaker 3: synthesize a virtual telescope with an effective baseline or diameter
Speaker 3: of up to one hundred and thirty meters.
Speaker 2: Wow, that solves the size problem.
Speaker 3: It does, But to make that work, the light waves
Speaker 3: from each telescope must arrive at the central gravity plus
Speaker 3: instrument at the exact same time, down to a fraction
Speaker 3: of a wavelength of light.
Speaker 2: But wait, the telescopes are physically located in different places
Speaker 2: on the mountain. The light traveling from the star hits
Speaker 2: telescope A slightly before it hits telescope B exactly.
Speaker 3: There is an optical path difference, so how do you
Speaker 3: fix that? To correct this, the light from each telescope
Speaker 3: is routed into subterranean tunnels equipped with delay line delay line. Yes,
Speaker 3: these are essentially highly precise mirrors mounted on carriages that
Speaker 3: physically move back and forth along rails to artificially lengthen
Speaker 3: or shorten the path the light travels.
Speaker 2: Wait, they have carts on rails underground moving mirrors to
Speaker 2: catch the light.
Speaker 3: Literally. Yes, they continuously adjust, compensating for the rotation of
Speaker 3: the Earth, ensuring that the light waves from all four
Speaker 3: telescopes aligned perfectly when they're combined.
Speaker 2: That sounds like science fiction.
Speaker 3: It's brilliant engineering. And the recent gravity plus upgrade was
Speaker 3: specifically what pushed this over the edge to find Wispit.
Speaker 2: To C so without that upgrade we wouldn't have seen it.
Speaker 3: Without that upgrade, the inner planet would have remained entirely
Speaker 3: hidden by the star's overwhelming light. The upgrade vastly improved
Speaker 3: the fringe tracking capabilities. That's the system that actively locks
Speaker 3: onto the phase of the combined light waves, and it
Speaker 3: integrated new more powerful adaptive optics directly into the array.
Speaker 2: Amazing.
Speaker 3: It allowed gravity plus to suppress the starlight and increase
Speaker 3: contrasts at incredibly tight angular separations, revealing wispit to C
Speaker 3: in the KBAN spectrum.
Speaker 2: Okay, so now that we understand what we're seeing and
Speaker 2: how we're seeing it, what does this actually change for
Speaker 2: the future of science. We have the mass, we have
Speaker 2: the orbits, we have the spectroscopy and the instrumentation. Now
Speaker 2: we have to contextualize this. We have a four point
Speaker 2: nine jupiter mass planet at sixty AU and are roughly
Speaker 2: ten jupiter mass planet at fourteen AU, all forming in
Speaker 2: a system that is only five million years old. How
Speaker 2: does this architecture challenge the existing models of planetary evolution
Speaker 2: because from what I read, the timeline here is causing
Speaker 2: a major headache for the standard core accretion model.
Speaker 3: Oh, it is causing a profound reevaluation of the mass.
Speaker 2: Let's get into it.
Speaker 3: Okay, So in the standard model of gas giant formation,
Speaker 3: known as core accretion, a planet must first build a
Speaker 3: solid core microscopic dust grains in the disc collide and
Speaker 3: stick through electrostatic forces, growing into pebbles. These pebbles then
Speaker 3: undergo streaming instabilities, clumping together to form kilometer sized planetesimals,
Speaker 3: basically building blocks. Yes, these planetesimals collide and merge in
Speaker 3: a process called oligarchic growth until they form a rocky,
Speaker 3: icy core roughly ten times the mass of Earth.
Speaker 2: And once it hits that ten earth mass threshold, what happens?
Speaker 3: Well, at that point, the gravity is strong enough to
Speaker 3: trigger runaway gas accretion starts pulling in the hydrogen and
Speaker 3: helium to become a jupiter.
Speaker 2: But you said there's a problem with the timeline.
Speaker 3: Yes, the rate at which planetesimals collide and grow depends
Speaker 3: heavily on their orbital velocity and the density of material
Speaker 3: close to the star. Orbital periods are short and density
Speaker 3: is high, so a core can build relatively quickly.
Speaker 2: Makes sense.
Speaker 3: But at sixty AU, where WISPIT two B is located,
Speaker 3: the orbital periods are centuries long and the solid material
Speaker 3: is sparse. Right, standard core accretion models suggest it should
Speaker 3: take tens of millions of years to build a ten
Speaker 3: earth mass core at sixty AU but Wispit two is
Speaker 3: only five million years old.
Speaker 2: And Whispit two B is already a fully formed five
Speaker 2: jupiter mass giant exactly, so the timeline doesn't work. The
Speaker 2: planet is too big, it's too far out, and it's
Speaker 2: too young. Does that mean the alternative theory, disk instability,
Speaker 2: is the answer.
Speaker 3: Well, disk instability posits a completely different top down mechanism.
Speaker 3: It argues that if a protoplanetary disk is massive enough
Speaker 3: and cold enough, the gravity of the gas itself overwhel
Speaker 3: olms the thermal pressure keeping it stable.
Speaker 2: Okay, so the gas just collapses on.
Speaker 3: Its own exactly, portions of the disk fragment and collapse
Speaker 3: in on themselves directly. It rapidly forms massive gas giants
Speaker 3: without ever needing to build a solid core first.
Speaker 2: And is that fast enough?
Speaker 3: Yes, this process can happen in a few thousand years,
Speaker 3: easily satisfying the five million year age limit of Whispit too.
Speaker 2: Wow. Okay, but there's a catch with disk instability too,
Speaker 2: isn't there.
Speaker 3: Always a catch? The catch is thermodynamics, Of course, it is.
Speaker 3: For a clump of gas to collapse under its own gravity,
Speaker 3: it must be able to cool rapidly. Why because as
Speaker 3: it collapses, it heats up, increasing thermal pressure, which causes
Speaker 3: the clump to bounce back and dissipate. It can only
Speaker 3: permanently collapse if the cooling time is shorter than the
Speaker 3: dynamic time scale of the.
Speaker 2: Collapse, so it has to cool off faster than it
Speaker 2: heats up.
Speaker 3: Exactly now, at sixty AU, the disc is cold and
Speaker 3: optically thin enough to cool efficiently, making disk instability a
Speaker 3: highly viable mechanism for wispit to b.
Speaker 2: Let me guess at fourteen AU, where whisp it two
Speaker 2: C lives it's too hot to cool efficiently.
Speaker 3: You nailed it. At fourteen AU, the disc is optically
Speaker 3: thick and much warmer. The cooling times are generally too
Speaker 3: long for disk instability to function. A clump would heat
Speaker 3: up and expand before it could ever form a planet.
Speaker 2: So wait, whisp it two C sits too close for
Speaker 2: disk instability, but whispit two B sits too far for
Speaker 2: standard core accretion. Yes, the system is defying both models simultaneously.
Speaker 3: Which is precisely why co author Christian Ginsky described whisp
Speaker 3: it too as a critical laboratory for the entire planetary system.
Speaker 3: It's forcing us to rethink everything.
Speaker 2: So how are they reconciling this. What's the leading hypothesis?
Speaker 3: The current leading hypothesis to reconcile this is an accelerated
Speaker 3: version of core accretion driven by the aerodynamic drag we
Speaker 3: discussed earlier.
Speaker 2: Oh, pebble acretion the.
Speaker 3: Head one thing again exactly if the ten earth mass
Speaker 3: core isn't built by slowly crashing massive planet tesimals together,
Speaker 3: but instead by sweeping up millions of millimeter sized pebbles
Speaker 3: that are constantly drifting inward, the growth rates skyrocket.
Speaker 2: Oh, because it's just gobbling up a steady stream of food.
Speaker 3: Right, Pebble accretion bypasses the traditional timescale bottlenecks. It potentially
Speaker 3: allows a core to form at sixty au within a
Speaker 3: million years, triggering the gas runaway fast enough to explain
Speaker 3: wisp it to.
Speaker 2: B That is just incredible.
Speaker 3: And if we connect this to the bigger picture, moving
Speaker 3: from one anomaly like PDS seventy to now having multiple
Speaker 3: systems proves this is a common cosmic process. We are
Speaker 3: actively building a catalog of birth sites.
Speaker 2: And we have even better tools coming online soon.
Speaker 3: Oh. Absolutely, wispit iiO is now a prime target for
Speaker 3: the James Webs based telescope to probe the disc chemistry
Speaker 3: and atmospheres, and the upcoming extremely large telescope might even
Speaker 3: be able to image that suspected the planet.
Speaker 2: I can't wait to see those images, but I have
Speaker 2: to ask about planetary migration. So what does this all
Speaker 2: mean for the layout? We have these two massive bowling
Speaker 2: balls orbiting in the disc. Once the gas fully dissipates
Speaker 2: and the disc is gone, are they going to stay
Speaker 2: put in these orbits of fourteen and sixty au or
Speaker 2: will they act like cosmic bowling balls, migrating inward and
Speaker 2: disrupting the formation of other worlds.
Speaker 3: Migration is almost a certainty. The current orbits are heavily
Speaker 3: influenced by the mass of the gas disc. Because WISP
Speaker 3: pit to B and two C are massive enough to
Speaker 3: carve deep gaps, they enter what is known as type
Speaker 3: two migration.
Speaker 2: What does that mean?
Speaker 3: It means they become gravitationally locked to the viscous evolution
Speaker 3: of the disc itself. As the disc slowly accretes onto
Speaker 3: the star over millions of years, the planets will be
Speaker 3: dragged inward with it.
Speaker 2: So WHISP two C could migrate from fourteen AU down
Speaker 2: to five AU or even become a hot Jupiter skimming
Speaker 2: the surface of the star.
Speaker 3: It is entirely possible. Furthermore, once the gas dissipates, the
Speaker 3: dampening effect it has on the planet's eccentricities disappears.
Speaker 2: Meaning their orbits could get wild.
Speaker 3: Yes, if wisp IT two, B and T c end
Speaker 3: up in a gravitational resonance where their orbital periods align
Speaker 3: in a simple integer ratio, the gravitational perturbations will amplify
Speaker 3: This can lead to chaotic scattering.
Speaker 2: What happens during chaotic scattering.
Speaker 3: Well, one planet could be flung into a highly elliptical
Speaker 3: orbit while the other is ejected from the system entirely.
Speaker 2: Just thrown out into deep space.
Speaker 3: Exactly, and this kind of violent orbital reshuffling is exactly
Speaker 3: what we believe happened in our own Solar system during
Speaker 3: the Grand Tach and the Nice Model scenarios, where Jupiter
Speaker 3: and Saturn migrated inward and then outward, scattering rocky material
Speaker 3: and icy comets throughout the inner Solar.
Speaker 2: System, fundamentally shaping the environment that allowed Earth to form.
Speaker 3: Exactly, that is the.
Speaker 2: Perfect connection to make. As we synthesize this entire discussion,
Speaker 2: the monumental effort required to map the KBAN spectroscopy of
Speaker 2: whisp It two C, to utilize the delay lines of
Speaker 2: the VLTI underground tunnels, and to actively deform mirrors thousands
Speaker 2: of times a second to cancel the atmosphere. All of
Speaker 2: it serves a singular purpose.
Speaker 3: It really does.
Speaker 2: When we look at whisp It too, we aren't just
Speaker 2: looking at random gas giants in equila. We're not just
Speaker 2: cataloging abstract physics. We're looking into to a five million
Speaker 2: year old mirror reflecting the chaotic, highly complex, and violent
Speaker 2: four point six billion year old origin story of the
Speaker 2: very ground we stand on.
Speaker 3: We are watching the raw materials of existence organize themselves exactly.
Speaker 3: And you know, the most profound aspect of that mirror
Speaker 3: is what we currently cannot see. What do you mean, Well,
Speaker 3: with all of our adaptive optics, the coronagraphs and the interferometry,
Speaker 3: we are only capable of resolving the outer massive gas giants,
Speaker 3: the five and ten jupiter mass titans sitting way out
Speaker 3: at fourteen and sixty AU right, But the region within
Speaker 3: five AU of the star, the terrestrial planet formation zone
Speaker 3: equivalent to where Earth, Venus and Mars sit in our
Speaker 3: system that remains hidden.
Speaker 2: Behind the glare of the young star.
Speaker 3: Yes, and behind the thickest, most optically dense regions of
Speaker 3: the inner disc. Within that unseen intercrucible, tiny grains of
Speaker 3: silicate dust and iron might be quietly colliding right now.
Speaker 3: Oh well, as we observe the majestic orbital dance of
Speaker 3: those outer gas giants, we have to acknowledge that hidden
Speaker 3: deep within the blinding light, the microscopic foundations of a rocky,
Speaker 3: potentially habitable Earth like world might be violently forging itself,
Speaker 3: just patiently waiting for the dust to clear.
Speaker 2: It is a truly remarkable realization. The fact that we
Speaker 2: have the technological capacity to observe a solar system taking
Speaker 2: its first breath, and the theoretical frameworks to understand the
Speaker 2: mechanics driving it is a testament to the golden age
Speaker 2: of astronomy who are currently living it.
Speaker 3: It really is an exciting time for the field.
Speaker 2: Thank you for joining us on this rigorous exploration of
Speaker 2: whisp it too and the mechanics of planetary genesis. Keep
Speaker 2: looking up and keep questioning the universe around you.