Astronomers Discover Earth‑Sized Exoplanet 55 Light‑Years from Earth in Speculoos‑3

Scientists Set Their Sights on a New Exoplanet

Using NASA’s James Webb Space Telescope

The research team aims to delve into the surface characteristics of the distant exoplanet, leveraging the advanced capabilities of the James Webb Space Telescope to gather unprecedented data.

• Detailed imaging of surface textures and geology
• Analysis of atmospheric composition and potential mineral signatures
• Calibration of instrument sensitivity to faint stellar reflections

New Earth-sized Exoplanet Detected Around a Nearby Red Dwarf

Overview

A research team from the University of Liège has announced the discovery of a planet the size of Earth orbiting an ultra‑cool red dwarf star located roughly 55 light‑years from our planet. This find brings the distance of a potentially habitable world even closer to Earth on a cosmic scale.

Key Facts about the Star – SPECULOOS‑3

• Radius and Mass: About the same size as Jupiter.
• Surface Temperature: ~2,627 °C, significantly cooler than the Sun’s ~5,500 °C.
• Type: Ultra‑cool red dwarf, one of the smallest and dimmest stars in the Milky Way.
• Visibility: Monitored by several observatories from 2021 to 2023.

Planet Details – SPECULOOS‑3 b

• Classification: Earth‑sized planet.
• Orbital Period: Short enough that it transits its host star regularly, allowing detection with ground‑based telescopes.
• Location: Orbits close to SPECULOOS‑3, placing it in the star’s habitable zone where temperatures could support liquid water.

Why Ultra‑cool Red Dwarfs Matter

Red dwarfs comprise about 70 % of the stars in our galaxy but remain largely unexplored because of their faintness. Their low luminosity makes it challenging to spot orbiting planets, yet they are the last stars to burn before the universe goes cold and dark.

The SPECULOOS Initiative

The Search for Planets EClipsing ULtra‑Cool Stars (SPECULOOS) project was launched to investigate these elusive stars. In February 2017, it famously discovered the TRAPPIST‑1 system – an Earth‑sized red dwarf with seven rocky planets – establishing a foundation for future discoveries like SPECULOOS‑3 b.

‘Never-ending days and nights’

While the temperature on SPECULOOS‑3b may seem relatively low, the harsh radiation from its host star erodes any atmosphere the planet could hold. Scientists conclude that habitable conditions are almost impossible, and the chances of life existing there are negligible.

• No Atmosphere – The intense stellar radiation strips surfaces of gaseous envelopes.
• Liquid Water Impossible – Without an atmosphere, liquid water cannot persist, removing a fundamental ingredient for life.
• Habitability Probable None – Researchers deem the planet unsuitable for any form of continual life.

• The study helps contextualize the search for potentially habitable worlds around cooler stars.
• It provides a baseline for distinguishing truly life‑worthy planets from those merely in the same vicinity.

SPECULOOS‑3b orbits its star in roughly 17 hours, a day that is a single, unending rotation due to a tidally locked state. One hemisphere perpetually faces the star, presenting a continuous day, while the opposite side experiences eternal night.

Just as the Moon keeps one face toward Earth, this exoplanet’s strong gravitational pull keeps a single side always pointed at its parent star.

The research team intends to deploy NASA’s James Webb Space Telescope to interrogate the day‑side surface composition. This will be the first time a planet comparable in size to Earth is examined in such detail.

• Its characteristics enrich our understanding of planetary atmospheres and their limits.
• These insights are vital for identifying world conditions conducive to life elsewhere.

To dive deeper into the research, view the embedded media presentation above where experts elaborate on their findings.