Level 1 - Absolute Beginner

Scientists found a new planet. The planet is called Ross 318b. It is very close to Earth. It is only 18 light-years away. A light-year is how far light travels in one year.

Ross 318b goes around a star. The star is called Ross 318. The star is smaller and cooler than our Sun. This type of star is called a red dwarf.

The planet is in a special area called the habitable zone. In this area, it is not too hot and not too cold. Water can stay liquid. Liquid water is very important for life.

Scientists used special tools to find the planet. They watched the star for 15 years. The planet is bigger than Earth. It has 6 times more mass than Earth.

planet

a large round object that goes around a star in space

star

a large ball of hot gas that produces light in space

light-year

the distance that light travels in one year

red dwarf

a small, cool star that is much smaller than our Sun

habitable zone

the area around a star where liquid water can exist on a planet

liquid

a substance that flows and is not solid, like water

mass

the amount of matter in an object

scientist

a person who studies the world using experiments and evidence

Level 2 - Elementary

An international team of astronomers has discovered a new planet called Ross 318b. It orbits a star named Ross 318, which is only 18 light-years from Earth. This makes it one of the nearest potentially habitable planets ever found. The planet is a 'super-Earth,' meaning it is bigger than Earth but smaller than the giant ice planets in our solar system.

Ross 318 is a red dwarf star. Red dwarfs are the most common type of star in our galaxy. They are smaller and cooler than our Sun. Ross 318b takes only 39.6 days to complete one full orbit around its star.

The planet sits inside the habitable zone of its star. This means it receives enough energy to potentially keep liquid water on its surface. Ross 318b receives about 58 percent of the energy that Earth gets from the Sun. This is enough to keep water liquid if the planet has a rocky surface.

Scientists used a method called radial velocity to detect the planet. They measured tiny wobbles in the star caused by the planet's gravity. They used two powerful instruments called CARMENES and HIRES and collected data for 15 years. Now they want to study the planet further using the James Webb Space Telescope.

astronomer

a scientist who studies stars, planets and other objects in space

orbit

the path that a planet takes as it travels around a star

super-Earth

a planet larger than Earth but smaller than the gas or ice giants

galaxy

a very large group of stars held together by gravity, such as the Milky Way

surface

the outside layer or top of something

wobble

a small movement from side to side caused by another object's gravity

instrument

a tool or machine used for scientific measurement

gravity

the force that pulls objects toward each other

Level 3 - Intermediate

Astronomers have detected a potentially habitable world right on our cosmic doorstep. The planet Ross 318b orbits within the habitable zone of Ross 318, a red dwarf star located just 18 light-years from Earth - a figure that makes it one of the nearest candidate life-hosting worlds ever found. The discovery was published on the scientific preprint server arXiv on May 11, 2026, under the identifier arXiv:2605.11123.

Ross 318b is classified as a super-Earth, with a minimum mass of 6.21 times that of our planet. Its orbital period of 39.6 days keeps it receiving approximately 58 percent of the solar flux that Earth receives from the Sun. In planetary science, this places it squarely within what researchers call the conservative habitable zone - the range of distances where liquid water could be stable on a rocky surface under a range of atmospheric conditions.

The detection method was radial velocity, which measures the tiny Doppler shifts in a star's spectrum caused by the gravitational pull of an orbiting planet. As a planet tugs its host star, the starlight shifts slightly toward the red end of the spectrum when the star moves away, and toward the blue end when it moves closer. The scientists combined 15 years of measurements from two world-class spectrographs: CARMENES, based at the Calar Alto Observatory in Spain, and HIRES, at the Keck Observatory in Hawaii.

Crucially, photometric data from the TESS space telescope showed no transit signal, meaning the planet does not pass in front of its star from Earth's perspective. This rules out direct atmospheric measurements using transit spectroscopy, at least for now. A key next step would be follow-up observation with the James Webb Space Telescope using alternative techniques, such as direct emission spectroscopy or phase-curve analysis, to probe whether Ross 318b has an atmosphere capable of supporting liquid water.

preprint

a scientific paper shared publicly before it has been formally reviewed by other scientists

solar flux

the amount of energy received from a star per unit of surface area

Doppler shift

the change in the frequency of light or sound caused by relative motion between source and observer

spectrograph

an instrument that splits light into its component wavelengths to analyse its composition or motion

photometric

relating to the measurement of the intensity of light from a star or other source

transit

when a planet passes directly in front of its star as seen from Earth, causing a small dip in brightness

emission spectroscopy

a method of studying the light emitted by a planet or star to identify chemicals in its atmosphere

phase-curve analysis

a technique that measures how a planet's brightness changes over its orbit to infer surface or atmospheric conditions

Level 4 - Advanced

The announcement of Ross 318b (arXiv:2605.11123, May 11, 2026) adds a world of considerable astrobiological interest to an increasingly well-populated neighbourhood. At 18 light-years, the planet orbits the M-dwarf Ross 318 at a distance that places it among the five nearest candidate habitable-zone planets yet identified, a cohort that includes Proxima Centauri b at 4.2 light-years and Wolf 1061c at 14 light-years but that has, until now, been thinly populated relative to the statistical expectation from M-dwarf occurrence rates. The minimum mass of 6.21 Earth masses, derived from the radial velocity semi-amplitude, represents the planet's mass projected against the inclination of the orbit: the true mass is almost certainly higher, though model-dependent upper limits constrain it to the super-Earth rather than mini-Neptune regime with reasonable confidence.

The detection architecture rests on 15 years of high-resolution spectroscopic monitoring using two complementary instruments: the CARMENES visible and near-infrared spectrograph at Calar Alto (Spain), which provides sub-metre-per-second radial velocity precision in the wavelength range most accessible to M-dwarf stellar characterisation; and HIRES at Keck (Hawaii), whose longer baseline stretches the dataset into the 1990s. The dual-instrument approach is methodologically important: stellar activity on M-dwarfs - quasi-periodic spot modulation, flaring, chromospheric emission - can imprint spurious radial velocity signals at periods that mimic those of orbiting companions. Combining datasets with different wavelength coverage and instrumental systematics helps disentangle genuine Keplerian signals from stellar jitter, and the 39.6-day orbital period of Ross 318b sits conveniently distant from known stellar rotation periods for stars of this spectral type.

The stellar flux of approximately 0.58 Solar Earth equivalents (S-Earth) places the planet firmly within the conservative habitable zone as defined by Kopparapu et al. (2013), specifically the inner region bounded by the runaway greenhouse limit at roughly 1.0 S-Earth and the outer edge where CO2 condensation becomes an issue near 0.32 S-Earth. Whether this translates into surface habitability is, of course, a question entirely contingent on the presence, composition, and stability of an atmosphere - information inaccessible to radial velocity. TESS photometry has ruled out a transiting geometry, which forecloses the well-developed transit transmission spectroscopy toolkit that JWST has deployed so productively on worlds such as TRAPPIST-1e and GJ 1214b.

The community's interest will therefore turn to alternative observational strategies. Phase-curve thermal emission mapping - observing how the planet's dayside heat signature changes as it orbits - and direct imaging with the forthcoming Habitable Worlds Observatory (HWO), currently projected for a late 2030s launch, represent the most plausible paths toward atmospheric characterisation. In the near term, the discovery motivates additional radial velocity monitoring to refine the orbital eccentricity, which influences the time-averaged flux and hence the boundary conditions for climate modelling. Ross 318b may not be the closest potentially habitable world, but its proximity combined with a host star that is intrinsically less flare-active than many benchmark M-dwarfs gives it a legitimate claim to being among the most tractable targets for next-generation characterisation campaigns.