gas giant

In the depths of sub-Neptunes, the most common type of planet in the Galaxy, though not one you could stand on, silicate magma and hydrogen mix into a single supercritical cocktail. Previously, it was thought that beneath the dense hydrogen atmosphere lay a sharp boundary with molten silicate, like oil on water.

Deep inside a sub-Neptune, where pressures reach a hundred thousand bars and temperatures hit four thousand degrees, rock behaves like boiling soup. Heavy vapors of silicon and magnesium rise, cool, and fall back as a rain of solid particles.

On a sunny street, there's a house with a big family: a giant father who always sits by the window and a small child running around the yard. That's the TOI-4468 system: a gas giant hot Jupiter hugs the star, while a bit farther out circles a sub-Neptune — a planet smaller than Neptune but larger than Earth.

Two stars, AF Lep A and ε Indi A, have become the focus of close attention. Using the GHOST spectrograph on the Gemini telescope, astronomers split their light into colors and, from absorption lines, determined how much carbon, oxygen, sulfur, and thirteen other elements are in the stars' atmospheres.

A star is not just a distant sun. It's a cradle for planets, and its light carries the birth story of the entire system. The chemical composition of a star is its DNA. Astronomers peer into this DNA to understand why some stars host rocky worlds like Earth, while others host gas giants.

Jupiter's atmosphere resembles a layered cake, where each layer plays its role. Scientists took data from four instruments at once (VLT/MUSE, Cassini/VIMS, IRTF/SpeX, and Juno/JIRAM) and built a model of clouds and ammonia in the planet's equatorial zone, from 0.1 to 10 bar (pressure equivalent to hundreds of kilometers below Earth's…

Water comes in different varieties. Not just fresh or salty, but also "heavy"—when one of its hydrogen atoms is replaced by deuterium, its heavier cousin. Such water is called HDO, and it's a true cosmic passport: the amount of deuterium in water reveals where and when that water was born.

It takes the stellar pair J05+50 nearly two months to complete one orbit around their common center. From Earth, it appears as a faint point in the constellation Hercules — 4625 parsecs away. Photometry of the binary star only captures a steady flicker of brightness, like the pulse of a giant heart.

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…

In 2024, the team led by David Charbonneau pointed the Magellan telescope with the WINERED spectrograph at LHS 1140. During transit, high-resolution spectroscopy caught the absorption line of metastable helium at 10833 Å.

In a giant cosmic cradle, the Tarantula Nebula, astronomers took a close look at 122 massive stars, each at least 30 times heavier than the Sun. They measured the nitrogen abundance in their atmospheres, and the picture turned out to be unexpected.

In the Galactic bulge, where the light of billions of stars merges into a continuous glow, four cold giants passed unnoticed. You can't see them through a telescope — too far, too dim.

Forget the familiar images of planetary cores — a sharp boundary between rock and gas is a thing of the past. The Juno probe, diving into Jupiter’s gravitational field, and Cassini, into the embrace of Saturn, discovered that heavy elements are not gathered at the center but smeared over a vast region, as if someone carelessly shook a cocktail.

Massive stars are cosmic titans, living under the sign of indomitable energy. When such a star enters the B[e] supergiant phase, its radiation is so powerful that it would seemingly pulverize any molecule into atoms. The spectral lines, once systematized by Johann Balmer, blaze here with particular fury.

A ball, almost weightless for its size, circles its star every four days. Planet TOI-2195 A b is a real riddle: by mass it's slightly heavier than Neptune, yet bloated to Jovian volumes. If there were an ocean big enough, this exoplanet would float on its surface like a giant inflatable ball.

When a star dies, it turns into a white dwarf — a dense ball of carbon and oxygen the size of Earth. Predicted by Subrahmanyan Chandrasekhar, these objects were long thought to be lifeless graveyards.

A sub-Neptune is a planet that falls between Earth and Neptune in size. These worlds are abundant in our galaxy, but their internal structure has been hotly debated. New research shows that in their youth, these planets behave like a sponge soaked with water.

The birth of planets resembles the workings of a cosmic forge. Rocky blocks collide and fuse together. A powerful impact strikes a spark — material heats to white-hot and glows like cooling metal. Computer simulations show: the flash is visible from days to years, peaking at a tenth of the sun's light.

Hundreds of light-years away, there's a planet that looks like a giant mirror. LTT9779b reflects most of the light that hits it — far more than you'd expect from a Neptune-sized body. Astronomers have long debated what makes it so shiny: a thick carbon-rich haze or a layer of clouds. The James Webb Space Telescope has helped settle the debate.

Some 158 light-years away, around the dim star TOI-6894, a red dwarf, a planet moves leisurely. Its year lasts less than two Earth days, yet it is a cool world with an equilibrium temperature around 420 K, just a bit warmer than a sauna.

A world where a year lasts just one and a half Earth days, and the star in its sky is hundreds of times larger than our Sun. This is KELT-9 b — a gas giant heated to temperatures at which iron vaporizes. Its atmosphere is not just hot; it is literally boiling away into space, like steam rising from a giant cauldron.

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.

Previously, Uranus and Neptune were considered ice giants because of assumed thick layers of frozen water, methane, and ammonia. New calculations paint a different picture: deep inside them hides an ocean of hot magma, which under immense pressure has absorbed a colossal amount of hydrogen.

In the catalogs of exoplanets, there are many worlds with sizes between Earth and Neptune. They are divided into two groups: rocky super-Earths and gaseous mini-Neptunes. The Solar System has none of these, and scientists debate where they come from. The authors of the study looked into each planet's 'passport'—its orbit.

A planet the size of Neptune, but glowing white-hot. Beneath the clouds lies an ocean of magma capable of absorbing an entire hydrogen atmosphere. The new SEAMIST model is the first to trace how such dissolution changes a planet's fate from birth to old age. The big surprise is the mechanism of catastrophic boiling.

The atmosphere of Titan, discovered by Christiaan Huygens, is opaque to ordinary telescopes. But spectral analysis finds 'windows' of transparency — narrow regions where the haze parts.

Among the hundreds of moons in the Solar System, Nereid dances the most desperate dance: diving toward Neptune as close as 1.4 million kilometers, then soaring away to 9.7 million — all within less than an Earth year. An eccentricity of 0.75 — the brand of a captured wanderer.

A street where houses have just been built. Some shine with clean windows, others are covered in construction dust. That's roughly what galaxies looked like when the universe was only a few hundred million years old. The new James Webb telescope peered into that era and saw dozens of bright star islands.

Using the JWST space telescope, astronomers conducted a chemical analysis of the centaur Chiron, an icy body from the fringes of the Solar System. It turns out its gas activity resembles a layered cake. Carbon dioxide evaporates from the surface, forming a top crust.

In the standard picture, black holes are the undisputed density champions: all their matter is squeezed into a single point. Imagine the entire mass of Mount Everest packed into a grain of salt. But physicists have found a theoretical trick.

If you don’t stir a layered cocktail, the heavy syrup sinks to the bottom. A young planet is much the same — a seething ocean of molten rock. As it cools, minerals crystallize: some, like iron, get heavy and sink, while others float. You’d think a dense layer would pile up at the core.

Beyond Neptune, in the icy belt, astronomers watched as object (612533) 2002 XV93 momentarily occulted a distant star. Using метод прохождений (when a planet dims the star's light for a second, like a fly in front of a lamp), Уильям Боруки and Дэвид Шарбонно determined: the light not only dimmed but also shifted…

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.

A giant planet hangs in space in complete solitude, separated from its star by a distance 160 times greater than the path from the Sun to Pluto. The light from its parent star arrives so faintly that the surface temperature barely exceeds 200 degrees Celsius — about as warm as a well-heated sauna.

A planet's magnetic field is like an invisible shield: it catches charged particles from the solar wind and stretches out behind the planet into a long tail, like a fluttering scarf.

Titan is a cold world with methane lakes and a dense orange atmosphere. But beneath the icy crust, warm puddles may hide, formed after meteorite impacts. In such a puddle, like a chemical flask the size of Selk Crater, simple gases from the air, hydrogen cyanide and acetylene, mix.

A baker adds more sugar to the dough, and the pie turns out different. So it is with a star: the composition of its "dough"—the cloud of gas and dust from which planets are born — determines what worlds will form around it.

Through a telescope, you can see a galaxy that looks like a giant glowing pinwheel. Its disk stretches thirty thousand light-years across — a third of the diameter of our Milky Way. But the most astonishing part: this pinwheel already existed just two billion years after the birth of the universe.

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.

Around the star Epsilon Indi, visible to the naked eye from the Southern Hemisphere, orbits a planet the size of Jupiter. The temperature there is like a good freezer: minus 200 degrees Celsius. The James Webb Space Telescope has for the first time directly imaged it and measured the light the planet emits in the thermal range.