object

terrestrial exoplanet

Rocky planets orbiting stars, often red dwarfs, with Earth-like composition but varied conditions.
105 related articles

Description

Terrestrial exoplanets are rocky worlds orbiting stars other than the Sun, with compositions dominated by silicates and metals, similar to Earth's. They range from scorching lava spheres to frigid ice-covered plains, and their conditions depend heavily on their distance from the host star, the star's type, and the planet's own geological activity. The study of these planets is central to understanding planetary formation, the potential for habitability beyond our solar system, and the diversity of planetary systems in the galaxy.

History

The first confirmed terrestrial exoplanet was discovered in 1992 around a pulsar, and the first around a Sun-like star, 51 Pegasi b, was found in 1995, though it is a hot Jupiter. The first truly rocky exoplanet, Kepler-10b, was confirmed in 2011 by NASA's Kepler mission.

How it works

These planets form from the accumulation of solid material in the protoplanetary disk around a young star, typically closer in than the ice line where volatile compounds remain solid. Their internal structure usually consists of a metallic core, a silicate mantle, and a thin crust, but the exact composition and thickness of these layers vary with the planet's mass and formation history. Surface conditions are shaped by stellar radiation, tidal forces, and internal heat, which can drive volcanism, plate tectonics, or a runaway greenhouse effect.

In practice

Terrestrial exoplanets are prime targets in the search for biosignatures, as their atmospheres can be analyzed with telescopes like the James Webb Space Telescope to look for gases that might indicate life.

Fun fact

Some terrestrial exoplanets, like the 'super-Earth' 55 Cancri e, may have surfaces covered in oceans of lava due to their extreme proximity to their host stars.

Concept graph →

Related articles · 105

Scales Where Overly Heavy Planets Tip the System
Astronomers catch distant planets by the trembling of their stars: an invisible companion tugs the star toward us and away, and its light subtly shifts in color. But that trembling tells only half the truth. If the planet's orbit is tilted to our line of sight, only part of its weight rocks the star, so telescopes reveal not the true mass but its shadow.
The Cosmic Compass: Why the Galaxy Gives Up Earlier Than We Thought
The night sky looks serene, but it is actually pierced by an invisible rain of charged particles: cosmic rays. Scientists have long tried to figure out where the most energetic ones are born. Until recently, it was thought that our Galaxy supplies particles up to about 4 EeV, the so-called "ankle" in the spectrum.
Stellar2026-08-272 minarXiv:2608.27344
X-ray passports for habitable worlds
Twelve stars have received X-ray passports. Now, for each of them, we know the exact radiation dose received by a planet in the habitable zone, the region where liquid water is possible.
A Pressure Cooker with Three Settings: How Disk Gas Forged the First Rocks
Three cabinets full of rocks. In one, metallic grains and the gray mineral enstatite; in the second, the same grains but with rusty streaks; in the third, layered clays swollen with water. All three sets were pulled from meteorites that fell to Earth: chondrites. They were born in the same gas-and-dust disk around the young Sun, yet somehow turned out so different.
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.
A Cosmic Shoal and an Airless Valley
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.
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.
High Energy2026-08-082 minarXiv:2608.08243express
Radio Beacons with a Minute-Long Rhythm: Who Lights Them Up
A lighthouse that blinks not every second but once every few minutes or even hours. That is exactly how long-period radio transients behave — cosmic sources discovered only recently.
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.
Exoplanets2026-08-051 minarXiv:2608.04512express
Tides Steal Moons from Close-In Planets
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.
Shadow Theater at TW Hydrae: Webb Catches the Hidden Drama of Planet Birth
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.
Galaxies2026-07-272 minarXiv:2607.24929
Cosmic Cross-Pollination: How Galaxies Enrich Their Neighbors with Metals
In 1,433 pairs of galaxies scattered across the sky, astronomers noticed an unusual pattern. Neighbors located 'above' or 'below' a massive stellar system contain up to a quarter more oxygen than those lying in the plane of its disk.
Stellar2026-07-272 minarXiv:2607.25055
Heavy seed in a magnetic cocoon
A star's radius drops by a thousand kilometers. Not because its mass increased, but because its own magnetic field squeezed the crust like an invisible corset.
A Symmetric Shadow in the Chaos of Tabby's Star
Tabby's Star, a beacon in the cosmic sea, has baffled astronomers since 2015. Its light flickered not in the rhythm of planets, but as if scattered by a storm — deep dips, sharp spikes. But amid this chaos, a smooth, nearly perfect dip was found. The eye of the storm.
Exoplanets2026-07-212 minarXiv:2607.19632express
Planetary Collisions and Their Hydrogen Coat
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.
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.
Icy Origins: Most Hot Jupiters Come from the Cold
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…
Waltz of Invisible Moons: The First Spectroscopic Find
The gravitational dances of celestial bodies long remained silent to astronomers. We learned to catch the shadows of planets against stars with the transit method — a breakthrough that delivered thousands of worlds thanks to William Borucki and his Kepler telescope.
Stellar Palimpsests: How We Read the History of Swallowed Planets
Every star is a living archive, and its spectrum a multilayered manuscript. Over billions of years, the history of the galaxy is written into it: the galactic chemical evolution of the Milky Way leaves a smooth trace in elemental abundances.
Invisible Planet in Warped Light
The light of a distant star is no perfect beacon. Passing through the gravitational field of another star, it bends, splits, and magnifies, creating a fleeting Einstein ring in the sky. This is how gravitational microlensing manifests, predicted by Fritz Zwicky back in the 1930s.
Gravitational Infancy: Record Orbits in the Cradle of HD 114082
In deep space, 95 parsecs from Earth, nature is assembling a planetary clock. The model HD 114082 is a prototype, only 15 million years old. Two massive pendulums — exoplanets b and c — are already swinging with periods of 225 and 314 days, but the whole mechanism is still covered in the construction dust of a debris disk.
Cosmic Debt: How a Planet's Mass Locks Civilizations Forever
Every civilization is born with a gravitational debt. The home planet's mass determines the loan amount, and the Tsiolkovsky equation is the interest rate applied to each kilogram of payload. To send a probe to the stars, you have to pay with fuel, and the debt grows exponentially.
Geophysics2026-06-242 minarXiv:2606.26042express
Magnetic Portrait of Earth's Core
Earth's magnetic field is like an invisible shield that protects us from cosmic radiation. But if you look closely at its long-term averaged pattern, you'll notice that this shield isn't perfectly smooth: it has its own "seams" and "patches." New research using computer simulations of the geodynamo shows that…
Instrumentation2026-06-241 minarXiv:2606.26296express
The Indigenous Perspective on the Drake Equation
The Drake Equation is an attempt to guess the number of intelligent civilizations in our Galaxy. It’s like counting finished cakes in an unknown bakery: you know the ovens (stars), the baking sheets (planets), and the baking time. But were eggs added to the batter? Western science, relying on a single earthly recipe, considers them a rare ingredient.
Exoplanets2026-06-221 minarXiv:2606.23789express
James Webb Fishes Out an Invisible Planet from a Dusty Disk
Using James Webb, astronomers 'fished out' a third giant planet from the murky dust disk of the star β Pictoris. Two others were already known, but this one was hiding in the bright light, like a fish in muddy water.
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.
Exoplanets2026-06-182 minarXiv:2606.20249express
How a Planet's Breath Shapes Its Fate
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.
Exoplanets2026-06-182 minarXiv:2606.20789express
How Tidal Waves Sort Planets
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.
Exoplanets2026-06-171 minarXiv:2606.19487express
A Planet's Rotation Revealed Its Fiery Secrets
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.
Exoplanets2026-06-161 minarXiv:2606.18355express
The Iron Planet Isn't So Iron After All
A cosmic sprinter on a short track: that's how you might describe planet GJ 367 b. It whips around its star in just 7.7 hours. This world is slightly smaller than Earth but has a personality: it was once thought to be nearly a solid ball of iron.
Exoplanets2026-06-161 minarXiv:2606.18410express
Super-Earths and Mini-Neptunes: Two Fates
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.
Stellar2026-06-152 minarXiv:2606.16782express
Stellar Freckles in X-rays
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.
General Relativity2026-06-122 minarXiv:2606.14894express
How a black hole's companion loses its coat
When a piano falls into an abyss, we think about the abyss. We don't think about the piano's cover. In much the same way, astrophysicists have for decades studied extreme close encounters between small bodies and massive black holes. They focused on the black hole itself and what orbits it. But what the 'bullet'—the small object heading toward doom — is wearing, almost no one asked.
Exoplanets2026-06-091 minarXiv:2606.11292express
How a Neptune-like planet flipped its star
A planet the size of Neptune wandered too close to its star. The star begins to pull the planet's outer layers onto itself — gas streams off the planet like water from an overflowing bucket. This process is called Roche-lobe overflow (astronomers use this term for the boundary beyond which a star can tear material away from a planet).
The Cosmic Forge: Why GJ 3929 b Lost Its Air
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.
Comet Spice: How a Late Influx of Matter Reshaped the Outer Solar System
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.