0
0
An international team of astronomers has identified a planet that bears an extraordinary resemblance to Earth — at least in size and orbital rhythm. The newly reported world, designated HD 137010 b, is almost exactly as large as our home planet and circles a Sun‑like star. Yet its surface, sealed beneath a frozen shell, reaches a frigid –70 degrees Celsius.
A Near Twin in a Distant System
The discovery, published in The Astrophysical Journal Letters, highlights a planet orbiting roughly 146 light‑years from Earth. HD 137010 b is rocky, only about six percent larger than Earth, and completes one orbit around its star in 355 days — remarkably close to Earth’s 365‑day year.
Found in the Archives
Rather than being spotted in new telescope data, the planet emerged from a fresh analysis of older observations collected by NASA’s Kepler Space Telescope during its K2 mission. Between 2009 and 2018, Kepler monitored the brightness of more than half a million stars, searching for the tiny dips caused when planets pass in front of them.
Citizen scientists from the Planet Hunters project first flagged an unusual signal. Alexander Venner, then at the University of Southern Queensland and now at the Max Planck Institute for Astronomy in Heidelberg, led the team that re‑examined the data.
Only one transit — a ten‑hour dimming of the star HD 137010 — was recorded in 2017. Normally, astronomers require multiple transits to confirm a planet. But the duration and depth of this single event allowed researchers to estimate the planet’s size and orbital period with surprising precision. Although the evidence strongly favors a planetary explanation, HD 137010 b remains officially classified as a planet candidate until further transits are observed.
At the Edge of the Habitable Zone
HD 137010, the host star, resembles the Sun but is about 1,000 degrees cooler and significantly dimmer. As a result, its planet receives less than one‑third of the sunlight Earth does. Models suggest a surface temperature between –68 and –70 degrees Celsius, similar to conditions on Mars.
This places HD 137010 b at the outer boundary of the habitable zone, where liquid water could exist under the right circumstances. Without additional warming, the surface would likely be entirely frozen. However, simulations indicate that a dense, carbon‑dioxide‑rich atmosphere could trap enough heat to create milder conditions.
Why the Discovery Matters
More than 6,000 exoplanets have been identified to date, but most are gas giants or scorched worlds orbiting extremely close to their stars. Earth‑sized planets around Sun‑like stars are rare — and often too distant for detailed study.
HD 137010 b stands out because it is both nearby and orbiting a bright, Sun‑like star, making it a promising target for future atmospheric investigations. With next‑generation telescopes, scientists may eventually search its skies for gases such as oxygen or methane, which could hint at biological activity.
Before that can happen, astronomers must catch additional transits — a challenging task given the planet’s long orbital period. Still, the prospect of studying such an Earth‑like world so close to home has energized the exoplanet community.
- source: orf.at/picture: pixabay.com
This post has already been read 67 times!
