protoplanetary disk dynamics

In a dense cloud of gas and dust where massive stars are born, two young stars recently passed very close to each other. Their dance has lasted only about sixty years, and astronomers have now seen it in detail for the first time.

A filament of the cosmic web stretches through the young universe, and strung along it like beads on a necklace are galaxies. In the core of the SSA22 protocluster, which in a few billion years will become the center of a massive cluster, these beads are still hot and dusty: stars are being born inside them, and cold gas serves as fuel.

A vortex in a magnetic disk usually behaves like a large spinning top: to keep it from toppling, you need a spacious platform and a strong self-field that returns it to the center. But what if you shrink the platform to the size of a virus? Then the usual support disappears, and the vortex should fall apart.

In the coldest, darkest corners of space, dust grains get covered in ice, like a window on a frosty day. This ice isn't just frozen water: it also contains carbon monoxide and carbon dioxide. From such ice, comets and planets may eventually assemble. But until now, it was unclear how the dust grain itself affects the ice that forms on it.

In the dark kitchen of the Taurus molecular cloud, 450 light-years away, dozens of planetary systems are being prepared. Each young star is a chef, and its protoplanetary disk is a counter piled with flour-like dust and steam-like gas.

After a supernova explosion, a dense ball the size of a city remains at the center — a newborn neutron star. It is hot, compressed, and rings like a bell after being struck. These tremors, the star's oscillations, emit gravitational ripples that sensitive detectors on Earth can catch.

The birth of a moon is a cosmic car crash. Two young planets collide, and a cloud of scorching debris swirls around the surviving world. From this disk, like clay on a potter's wheel, a satellite gradually takes shape. That's probably how our Moon came to be.

In the furnace of star formation, the heat reaches 900 degrees Celsius, like a glowing blast furnace. It is in this hellish heat that cosmic crystals are born. Astronomers have for the first time caught the moment when crystalline dust appears right during an accretion flare (when the star gobbles up surrounding gas) at the very young star EC 53, still cocooned in dense gas.

A stone falls into still water, and smooth rings spread across the surface. If the stone doesn't just fall but also spins, tiny whirlpools, vortices, appear on the surface. Light can do the same, only instead of water, it's space and time themselves.

Seventy-two protoplanetary disks, swirling cocoons of cosmic dust and gas, came under the gaze of the MIRI instrument on JWST. Most of them shoot outflows into space: dense conical structures and narrow, high-speed jets. They blast like fountains. This process is not accidental.

Two cities endure a series of fires. In one, the wind carries ash far beyond the outskirts, leaving the sky clear. In the other, ash settles as a dense veil, painting sunsets crimson. Roughly the same thing, just on a galactic scale, happens with supernova explosions, the final flares of massive stars.

In a single star system, two teams of planets orbit. Some follow neat paths, like figure skaters on an ice rink, avoiding collisions. Others crowd together, their trajectories cross, and sooner or later a cosmic accident occurs — a giant impact.

A tiny satellite, like a swimmer, cuts through invisible layers of gas in the bloated envelope of a red giant. Each orbit excites an acoustic wake — compression waves traveling through plasma.

Among the scorching exoplanets that circle perilously close to their stars lies the secret of their birth. Nearly three decades ago, Michel Mayor and Didier Queloz discovered the first such world, and since then astronomers have been tormented by the question: how does a gas giant end up pressed against…

Around some young stars where star formation has recently ended, there swirl not just dust rings but actual planetary battlefields — extreme debris disks.

Like an exquisite clockwork mechanism, a multi-planet system responds sensitively to the slightest nudge. And when the star at the heart of this mechanism dies, shedding its envelope and turning into a white dwarf, even a modest kick at a speed of 0.75 km/s can trigger a cascade of events, flinging entire worlds into interstellar emptiness.

Two million years away, around the young star CI Tau, a gas-dust disk whirls — a protoplanetary cradle. ALMA observations have already shown rings and gaps in it, but the finest details remained invisible: their width is smaller than the instrument's resolution.

WASP-121 b is not just a hot ball. It's a world where iron vaporizes and the sky glows with its own heat. A fresh look at it has revealed what 'ingredients' went into making it. The James Webb Space Telescope has for the first time clearly detected vaporized silicon monoxide in its atmosphere — a refractory substance usually locked inside dust grains.

A scorching rocky planet is like a pot of boiling soup, except its lid is the atmosphere. Gases escape from the magma, wrap the world in a thick blanket, and in turn influence how quickly the celestial body cools. For GJ 1132 b, which orbits so close to its star that a year lasts just one and a half Earth days, this connection is especially important.

A pot of boiling soup is shaken hard — the liquid sloshes, waves crash against the walls. Something similar happens inside a gas planet when it swings past its star on an elongated orbit. The star's gravity excites powerful internal waves in the planet, known as tidal fundamental modes. These waves can completely change the planet's fate.

A thick stew slowly cools in a pot. Suddenly, the flame beneath it flares up, and the stew begins to boil, breaking into many small whirlpools. Much the same happens to the disk of gas and dust around a young star when it experiences a flare — a sudden influx of matter from the disk onto the star.

Putting together the Solar System is like crafting a high-end tasting menu: the recipe isn't always set in stone — sometimes the final ingredient is added while the dish is already cooking.

A pot of boiling porridge, where instead of grains there are layers of oxygen and silicon, and the fire beneath is about to go out, and the star will collapse in on itself. Until now, astrophysicist cooks have used a simplified recipe: they assumed that bubbles and eddies in the porridge obey one and the same average temperature throughout the depth.

A massive star collapses, and a black hole is born, surrounded by a disk of incandescent plasma. For narrow jets to burst out of this disk, an ordered magnetic field is needed. But inside the star, it's tangled.

A spinning top that wobbles as it rotates: that's roughly how astronomers picture the neutron star in the binary system Hercules X-1. It completes one full turn on its axis every second, but its axis slowly traces a cone with a period of 35 days.

Planet WASP-121 b always shows the same face to its star, like a rock in a campfire. The dayside is so hot that ordinary hydrogen, the very stuff most of the universe is made of, can't take it: its molecules tear apart into individual atoms, and the temperature flips upside down: the higher you go, the hotter it gets.

In the scorching solar corona, where temperatures soar past a million degrees, float cold, dense clouds — solar prominences. They hang for weeks, neither falling nor dissolving, like icebergs in a boiling ocean. How they got there is a question that has puzzled astronomers for decades.

A neutron star is a spinning top with the mass of the Sun, crushed to the size of a city. It's born in the fire of a supernova and usually only slows its spin. But sometimes, for no apparent reason, it suddenly speeds up — such a jerk is called a glitch.

In a pot of boiling water, steam bubbles rise and pop. In the quantum world of a superfluid, bubbles behave differently: they can collide and give birth to vortices — tiny swirling flows, like whirlpools in a river. Scientists modeled such a liquid using a holographic approach.

In a disk of gas and dust around a young star, dust particles behave like sand grains in a stream of water: the gas flows faster, the dust lags behind, and friction arises between them. This friction can rock the magnetic waves that run through the disk. The galaxy is full of such disks: it is precisely in them that planets are born.

In cold clouds of interstellar gas, long, dense filaments stretch out. Inside them, like overcrowded incubators, future stars are maturing. For a long time, it was thought that within such filaments, everything was governed by gravity: matter smoothly flows toward the centers, where density increases and eventually a star ignites.

Young planetary systems resemble an orchestra that has just started rehearsing: all the musicians strive to play in the same rhythm.

Lithium is like a thermometer dipped into a star's interior. This light element is destroyed at temperatures around 2.5 million degrees, so its abundance on the surface tells us how deeply the star's material has been mixed.

The James Webb Space Telescope is gazing more and more at exoplanets — worlds orbiting alien stars. Some of them are scorching rocky spheres, tidally locked with one side forever facing their star. There, rock melts into oceans of liquid lava. How does this lava move?

The young star HL Tau is surrounded by a disk of gas and dust — the cradle of future planets. Inside this disk, the gas is not static: it orbits the star, but it also trembles and churns, like water in a raging river. Astronomers have now directly measured the strength of this churning for the first time.

In the cold outer reaches of the Solar System, water is considered the main building material for ices. But some comets and distant icy bodies have an unusually high ratio of carbon monoxide (CO) to water, as if a scoop of ice cream suddenly had too much syrup. The authors of a new study set out to find where this imbalance comes from.

In the cold gas clouds where giant stars are born, everything is churning with motion. Gas compresses, swirls, and fragments into clumps — the future stars. For a long time, it was thought that the magnetic field brought order here: like invisible threads, it stretched clumps perpendicular to itself. But new observations showed the opposite.

Planets are born from dust. In a disk around a young star, tiny dust grains collide, stick together, and gradually grow like a snowball rolling down a hill. But there's a catch: the gas in the disk moves faster than the dust and drags on it, preventing it from clumping into large chunks. For dust to stick together, there needs to be enough of it.

In a protoplanetary disk, a cloud of gas and dust around a young star, dust grains don't just fly in circles. They are carried by the gas flow, like sand by the wind, and in turn alter that flow. Layers emerge, sliding past each other, and at their boundaries an instability arises — waves and vortices.

Dust grains in the disk around a young star stick together, grow, and will eventually become planets. But to know how much planet-building material each disk holds, you need to measure its mass and size. You can't weigh a distant cloud directly: you have to infer it from the dust's radiation.