object

hot jupiter

A class of giant exoplanets with very high atmospheric temperatures due to close proximity to their star.
38 related articles

Description

Hot Jupiters are a class of exoplanets with masses comparable to Jupiter but orbiting extremely close to their host stars, resulting in atmospheric temperatures of 1,000 K or more. These planets are often tidally locked, meaning one side permanently faces the star, creating extreme temperature contrasts between the day and night sides. Their study provides insights into planetary formation, atmospheric dynamics, and the evolution of planetary systems under intense stellar radiation.

History

The first hot Jupiter, 51 Pegasi b, was discovered in 1995 by Michel Mayor and Didier Queloz, a finding that earned them the 2019 Nobel Prize in Physics.

How it works

The high temperatures cause the planet's atmosphere to expand, and the intense stellar radiation drives strong winds that redistribute heat. Observations of their spectra reveal the presence of molecules like water, carbon monoxide, and even vaporized metals in their atmospheres. Some hot Jupiters show evidence of atmospheric escape, where the heated gas overcomes the planet's gravity and streams away, sometimes forming a comet-like tail.

In practice

Hot Jupiters serve as natural laboratories for testing atmospheric models and radiative transfer codes, which are also used in climate science and stellar astrophysics.

Fun fact

Some ultra-hot Jupiters have atmospheres so hot that they contain vaporized iron and silicate clouds that rain molten glass on the night side.

Concept graph →

Related articles · 40

The Neighbor Who Wasn't Kicked Out
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.
Stellar2026-08-141 minarXiv:2608.13895express
Planets from foreign galaxies hiding in the Milky Way
The night sky seems unchanging, but galaxies constantly exchange matter. The Milky Way, like a great river, absorbs smaller streams — dwarf galaxies. Along with their stars, planets may also come to us.
Stellar2026-08-072 minarXiv:2608.07331express
The Stellar Family Tree of Planets
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.
Tidal Swings of an Eccentric Jupiter
Every 165 days, the giant planet dives toward its star, nearly grazing its fiery corona, then flies off into the icy void. This is TIC 241249530 b — an exoplanet with a record eccentricity of 0,94.
Cosmic Jazz: Three Finales of an Encounter with a Black Hole
The universe teems with the invisible: about 85% of matter neither emits nor absorbs light. This hidden mass, first suspected by Vera Rubin from the anomalously fast rotation of galaxies, we call dark matter.
Cosmic Carving: Birth of a Bloated Neptune from a Jupiter
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.
HEP Phenomenology2026-06-231 minarXiv:2606.25033express
Dark Matter at Supersonic Speed
Dark matter is the invisible scaffold that holds galaxies together. But how did it come to be? The standard answer: particles of dark matter once stopped colliding and "froze out" in the amount we see today. However, there's a trickier path — UFO, or ultra-fast freeze-out. Here, everything is like coffee that cools down and then heats up again as you carry it through a cold corridor.
Exoplanets2026-06-201 minarXiv:2606.21855express
What a Giant Planet Was Baked From
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.
Cosmology2026-06-121 minarXiv:2606.14827express
Dark Matter Sways Distant Planets
Think of a baby mobile: figurines dangling on threads, twitching at even a whisper of breeze. In the same way, planets on very wide orbits barely cling to their star's gravity, and they feel the faintest gravitational drafts. Astronomers have proposed turning such planets into detectors of dark matter.
Exoplanets2026-05-022 minarXiv:2605.01390express
Chemical Portrait of an Invisible World
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.
Exoplanets2026-04-292 minarXiv:2604.26850express
A Frozen Snapshot of Planet Birth
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.
Exoplanets2026-04-281 minarXiv:2604.25253express
Jupiter's Tail Is Wired Differently
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.
Exoplanets2026-04-251 minarXiv:2604.23448express
Giant Planet or Twin World?
Astronomers pointed JWST at a planet near the star Epsilon Indi — a giant gas ball resembling Jupiter, just 12 light-years away. In thermal images, the planet shone like a lantern. But nearby they noticed a faint dot — like a firefly. Calculations showed that two objects describe the picture better than one. However, it's most likely a lens flare — like a ghost of a lamp.
Exoplanets2026-04-211 minarXiv:2604.19179express
A Planet Rolling Against the Stellar Current
The carousel spins all the horses in one direction, but one stubbornly gallops against the flow. That's exactly how the planet TOI-1710 b behaves around its star. Using the HARPS-N and GIANO-B instruments, astronomers measured its tilt at 149 degrees. That's nearly a 180-degree flip, meaning the planet orbits "backward" relative to the star's rotation.
Exoplanets2026-04-201 minarXiv:2604.18579express
Quiet Stars, Loud Discoveries
The TESS telescope photographed the sky for a full year, but its standard pipeline skipped over dim stars. The T16 project took the same images and cleaned them from scratch — resulting in 83,717,159 light curves, like EKGs for every star. Planets passing in front of their star briefly dim it, and these dips in the EKGs are what we look for.
Exoplanets2026-04-081 minarXiv:2604.06969express
A Distant Planet's Magnetic Pulse
The star GJ 436 is a dim red dwarf, and orbiting it is a Neptune-sized planet on a nearly vertical, tilted orbit. Astronomers spent 18 years taking spectra of this star to track its spots and flares. Suddenly, a rhythm emerged in the data that matched neither the star's rotation nor its 8-year activity cycle. This rhythm exactly followed the planet's orbit.
Exoplanets2026-04-011 minarXiv:2604.00535express
Roiling Lava Ocean Doesn't Shift the Hot Spot
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?
Cosmology2026-03-241 minarXiv:2603.23195express
Hot Gas in Galaxy Groups: Why It's Dimmer Than It Should Be
A pot of boiling water sits on the stove: the higher the heat, the hotter the water and the more steam escapes. Hot gas in galaxy clusters behaves much the same way. But in small galaxy groups, this "steam" leaks out faster than you'd expect from the temperature alone.
Galaxies2026-03-131 minarXiv:2603.13471express
Cosmic Neon Sign: Gas Glows Brighter Than Stars
A cosmic neon sign lit up in an incredibly distant galaxy: almost all its light comes from hot gas, and the stars are lost in this glow. The James Webb telescope recorded that the gas, a mix of hydrogen and helium, is so heated that it glows on its own.
Galaxies2026-03-051 minarXiv:2603.05434express
The Galaxy Thermometer Is on the Fritz
The gas in a galaxy glows like a neon sign, and by the color of that glow, astronomers can tell how hot it is. The logic is simple: the more heavy elements (which astronomers call metals) in the gas, the better it cools. So galaxies rich in metals should have cooler gas. But new observations show the opposite.
Exoplanets2026-02-232 minarXiv:2602.19986express
Sodium in the Sky of a Distant Planet
When a planet passes in front of its star, some starlight filters through its atmosphere. Gases in the atmosphere block certain colors and let others through, like the colored glass of a stained-glass window. By seeing which colors are dimmed, you can figure out what the air of a distant world is made of.
Exoplanets2026-02-231 minarXiv:2602.20155express
Mountains on Exoplanets Prevent Eternal Winter
For exoplanets that always face their star with one side, the night side is doomed to eternal cold. But mountains can turn things around. Surface irregularities shake up the ocean of air, steering moisture flows across the day-night boundary. Once in the dark, water freezes into clouds, and clouds act like a blanket: they trap heat and keep the world from cooling down.
Exoplanets2026-02-181 minarXiv:2602.16816express
The Planet That Wrapped Its Star
A planet hugging its star is like an ice cube forgotten on a scorching skillet. The ice melts and evaporates, except instead of water, it's hydrogen and helium from the planet's upper layers.
Exoplanets2026-02-051 minarXiv:2602.05168express
Surprise Planet Around a Young Star
Astronomers caught the young planet AU Mic b in the act of hiding behind its star. The Spitzer telescope tracked its infrared glow: as the planet slipped behind, the system's total light dimmed slightly. The dip was just 171 parts per million, like a single drop of ink in ten buckets of water.
Exoplanets2026-02-032 minarXiv:2602.03498express
A Baby Hot Jupiter: Atmosphere, Winds, and a Hint of Heavy Water
Planet HIP 67522 b is quite young: it's only 17 million years old, compared to Earth's 4.5 billion. It's a hot Jupiter — a gas giant that orbits very close to its star, so its atmosphere is heated and puffed up.
Exoplanets2026-02-032 minarXiv:2602.03723express
Hot Jupiters Devoured by Their Stars
A giant planet circles too close to its star. With each orbit, it tugs on the star with its gravity, and waves are born deep inside the star, like ripples from a stone dropped into water. These waves damp the planet's orbit, and it spirals into the star. The star swallows the planet and starts spinning faster. Stellar rotation is the key clue.
Stellar2026-01-291 minarXiv:2601.21727express
Invisible Stars: How Galaxies Hide Their Secrets
Sometimes you find a movie ticket from three years ago in the pocket of an old jacket. You can't reconstruct the time from it, but you can figure out where the owner went. The same goes for hot subdwarfs — tiny stars in the late stages of life that shine mostly in ultraviolet. Their light is like that ticket: it tells you about the past, but reading it is tricky.
Exoplanets2026-01-261 minarXiv:2601.18877express
Why Giant Planets Often Have Slightly Stretched Orbits
A planet's orbit is its path around its star. If the path is perfectly circular, the planet always stays at the same distance from the star. But many planets have slightly stretched paths, like a running track in a stadium. Astronomers studied hundreds of giant planets around other stars and found a curious pattern.
Exoplanets2026-01-192 minarXiv:2601.13302express
Exoplanets2026-01-181 minarXiv:2601.12501express
Death of a Planet: A Bright Flare from Its Parent Star
When a planet approaches its star to a critical distance, tidal forces, the result of a sharp gradient in gravity between the near and far sides of the celestial body, tear it apart. This process ignites a cosmic funeral pyre: the planet's debris forms a glowing accretion disk around the star.
Exoplanets2026-01-161 minarXiv:2601.11280express
Cold Jupiters: Invisible Giants on the Outskirts
Jupiter is a colossal ball of gas that sits five times farther from the Sun than Earth. Now imagine a similar ball, but around another star, at a distance tens of times greater. These are called cold Jupiters, and they remain a puzzle: how did they get there? Astronomers studied four such planets around distant stars.
Exoplanets2026-01-162 minarXiv:2601.11313express
Dancing in Orbit: How Hot Jupiters Choose Their Path
Three distant giant planets circle their stars so closely that a year on them lasts just a few Earth days. These worlds are called hot Jupiters, and their orbits are a real puzzle: how did they end up right next to the star if they were born far away, in the cold outskirts of the system? One key clue is the angle at which a planet orbits relative to the star's rotation.
Cosmology2026-01-152 minarXiv:2601.10817express
A Distant Galaxy Cluster That Wasn't So Quiet After All
A city at night looks quiet from above, but life bustles in its neighborhoods: streets are blocked off, construction is underway, and equipment hums in basements. That's roughly how astronomers now see the galaxy cluster SPT-CL J2215-3537, located so far away that its light has traveled for more than 8 billion years.
Exoplanets2026-01-141 minarXiv:2601.09835express
Cosmic Billiards: How Planets Become Wanderers
Space works like a billiard table. Massive outer planets, like heavy balls, transfer their energy to light inner worlds. Such a gravitational kick can fling a small planet out of the stellar system. It turns into a free-floating wanderer — a rogue exoplanet without a star. Detecting these invisible bodies is hard: they neither emit nor reflect light.
Exoplanets2026-01-111 minarXiv:2601.07080express
Lava Oceans on Exoplanets: Tidal Heating and Stone Waves
An exoplanet — a planet outside our solar system — follows a slightly elongated orbit. With each revolution, it swings closer to its parent star and then farther away.
Exoplanets2026-01-092 minarXiv:2601.05799express
A Warm Belt Around Red Dwarfs
Two new planets are circling dim red stars. One is nearly the size of Earth, the other is three and a half times larger. Both lie in what astronomers call the warm zone: a region where starlight doesn't scorch the surface but also doesn't leave it in perpetual cold. The host stars are red dwarfs, the most common stars in the galaxy.
Exoplanets2025-12-081 minarXiv:2512.07695express
Exoplanets2025-11-051 minarXiv:2511.03392express
Warm Moons of Rogue Planets
The planet's gravity rhythmically squeezes and kneads the moon like dough: from this constant 'kneading', the interior heats up, and oceans of water can persist under the icy crust for ages. In the Galaxy, there are plenty of rogue planets, thrown out by supernova explosions.
Galaxies2025-08-294 minarXiv:2508.21678
Red dots versus blue excesses: two paths for black hole growth
Two houses with identical facades but different interior layouts: from the outside the V-shaped spectrum looks the same, but inside there are different light sources and different amounts of dust. That is exactly how the two populations of distant galaxies that astronomers have long confused appear.
Titanate Clouds Above a Scorching Giant
The dayside of WASP-121b is scorching at 2358 kelvins, hotter than the surface of many stars. Here, in perpetual light, the atmosphere does not just boil: it melts rock and turns it into gas. But not all gas stays gaseous. Some condenses into clouds, and those clouds hide titanium the way a trap hides its prey.