jwst exoplanet atmospheres

The orchestra is playing fortissimo, and someone in the third row is whispering. Hearing that whisper is the challenge astronomers face at the star HR 8799: four bright giant planets drown out the faint light of a possible fifth, hidden very close to the star. The HR 8799 system is a proving ground for direct exoplanet imaging.

The JWST space telescope aimed its lens at the scorching rocky world 55 Cancri e, and spotted a dense gas envelope. But the cooler TRAPPIST-1 b, which orbits a dim red dwarf, showed no envelope: just bare rock. The picture came out upside down: hot planets hold onto atmospheres, while cooler ones lose them.

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.

In March 2023, the James Webb Space Telescope pointed its instruments at the short-period comet 81P/Wild 2. This celestial body, about the size of a small town (nucleus radius around 1.77 km), is already familiar to scientists: in 2006, the Stardust probe flew through its tail and collected dust samples that were later studied in Earth laboratories.

2,41 hours. That's exactly how long a day lasts on SIMP 0136 — a lonely planet-like object 6,1 parsecs away. That's twice as far as Proxima Centauri. Its mass ranges from 12,7 to 17,8 Jupiter masses, placing it on the boundary between planet and star.

Edge of the spotlight. Remove the dazzling light of the central star, and a theater of shadows emerges. The James Webb coronagraph, like a dense curtain, hid the star TW Hydrae — and on a stage 120 astronomical units long (four times the distance to Neptune), its protoplanetary disk came alive.

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.

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…

When the JWST telescope breaks the light of a distant exoplanet into a spectrum, it reads a chemical chronicle. But this chronicle is not a monolithic truth; it's an atmosphere constantly rewritten by the star's radiation.

The light of a distant star carries within it the silent hum of the atmospheres of planets orbiting it. For a long time, capturing it was like trying to make out a whisper over a roaring waterfall. But with the advent of the 39-meter Extremely Large Telescope (ELT) and the ANDES spectrograph with a resolution of 100,000, this task is no longer hopeless.

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.

The James Webb Space Telescope has peered into a strange binary world. Here, a dead star, a white dwarf, slowly roasts its companion, a brown dwarf. The object, named ZTFJ0038+2030, completes a full orbit in just a few hours. One side of the brown dwarf always faces the white dwarf, much like the Moon faces Earth.

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.

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.

The planet WASP-121 b is a gas giant, heated to 2500°C. It always faces its star with one side, like a globe frozen under a lamp. But as it passes in front of the star's disk, its rotation reveals different facets to us — as if that globe were slowly turned, letting us peer into every corner.

A planet glides across a star's disk, and for a moment becomes a flashlight. It blocks a tiny patch of surface, revealing details that otherwise escape our view. That's exactly how astronomers peered into the dark spots on V1298 Tauri, a young twin of our Sun. They were aided by the James Webb Space Telescope JWST and three giant planets in orbit.

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.

A fire hose blasts into a snowdrift. The water doesn't just shove the snow aside — at the point of impact, spray, steam, and a roar are born. That's roughly how jets behave: narrow streams of matter shooting out from around a black hole at enormous speeds.

Red dwarfs are tireless blacksmiths of planetary fate. Their radiation, like a hammer, beats off gas envelopes, leaving only naked rocky cores. In the depths of the constellation Hercules, around the dim M-dwarf GJ 3929, orbits a world one-and-a-half times Earth's size, like a billet on an anvil.

Astronomers using the JWST (James Webb Space Telescope) have for the first time studied in detail the atmosphere of a young exoplanet, V1298 Tau c. This super-Earth, a planet more massive than Earth but less so than gas giants, is only 23 million years old.

A kindergarten where some kids are busy making sandcastles while others are already assembling building blocks. That's roughly what the V1298 Tau system looks like: it's only 20 million years old — by cosmic standards, it just left the nursery. Several planets orbit it, and two of them, b and e, turned out to be surprisingly different.

When a planet slips behind the edge of its star, the star backlights the planet's atmosphere, just as a setting sun illuminates clouds on the horizon. This brief moment, lasting only minutes, carries the imprint of the gases through which the starlight has passed.

A pot of boiling lava, sealed with a thick lid of gas. That's roughly what sub-Neptunes look like — planets that are common around other stars but absent in our own solar system. Beneath a thick hydrogen atmosphere sloshes a molten magma ocean.

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…

Steam over a boiling pot slightly tints the light of a flashlight: it blocks some colors and lets others through. That's roughly how we study the air of distant planets.

Light from a distant star seeps through a planet's gaseous envelope, and astronomers try to guess what that envelope is made of. That's how we study the atmospheres of worlds we can never touch. When a planet passes in front of its sun's disk, its gaseous veil briefly intercepts some of the rays.

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.

Astronomers aimed JWST at the rocky exoplanet LHS 3844 b — a world orbiting another star, where a year lasts just 11 hours. The planet is tidally locked: one side always faces the star, with a permanent scorch of 770°C, while the night side is plunged into icy darkness.

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.

The solar wind, a stream of charged particles from the Sun, slams into the tenuous gas that fills the space between the stars. The collision produces a faint X-ray glow. For astronomers, this is like fog in front of headlights: it obscures distant objects.

The smell of fresh bread unmistakably signals a nearby bakery. But to know if baking is happening right now, it's better to catch not the aroma itself but its intensification — the continuous stream of hot air from the oven. This everyday analogy helps grasp a revolution in the search for extraterrestrial life on exoplanets — planets beyond our solar system.

A world that for years refused to show its face. Planet GJ 1214 b is exactly such a case. It is larger than Earth but smaller than Neptune, and its dense envelope made the atmosphere invisible to telescopes: starlight passed through it without leaving clear traces. But astronomers' persistence and a new sensitive instrument provided the first clue.

A hot skillet on the stove glows in the dark, but if you cover it with a lid, the heat escapes more slowly and the surface doesn't look as bright. That's roughly the situation on planet HD 3167 b: it always shows the same face to its star, and the dayside is heated to temperatures that melt rock.

The light from a distant star is never steady. It shimmers like heat over hot asphalt. When astronomers pointed JWST at the star TOI 700, they saw this shimmer especially clearly: every 16 minutes, the brightness changed by a tiny fraction, just 46 parts per million.For comparison: if you placed a light bulb a kilometer away, this change would be…

When an exoplanet briefly eclipses its star, starlight passes through its air and absorbs its chemical taste. This technique, the transit method, is the core of how the James Webb telescope works.

Light from a distant star, passing through the atmosphere of planet K2-18b, left unusual "fingerprints" in its spectrum. Astronomers spent 420 hours collecting this light with the James Webb Space Telescope and split it into colors, like a rainbow.

When a planet passes in front of a star, the light pierces its atmosphere and absorbs the flavor of gases. Each gas leaves its color fingerprint in the light — a bitter or sweet stroke. Scientists try to read this recipe: what substances and in what proportions are mixed in the air of an alien world.

Seven hours: that's how long a year lasts on TOI-4552b. It whips around its star faster than some moons orbit Earth. The star is a dim red dwarf, four times smaller than the Sun, but the planet is so close that it receives hundreds of times more heat than we do.