How amateur volunteers discovered an icy, Earth-like exoplanet

HD 137010 b, a planet nicknamed "cold Earth"

Did you know that a new exoplanet was spotted thanks to amateur volunteers, without any professional astronomer initially noticing the signal? Named HD 137010 b, this candidate planet is slightly larger than Earth and orbits a star similar to our Sun, about 146 light-years away. Its nickname, "cold Earth," sums up its profile well: a size close to our own, but a temperature likely far more frigid.

This discovery was published on January 27, 2026 in The Astrophysical Journal Letters, by a team led by researcher Alexander Venner. What makes the story particularly remarkable is its origin: it comes from the participatory project Planet Hunters, which lets any volunteer examine the Kepler telescope's archives in search of suspicious signals.

This guide walks you through, step by step, how this kind of collaborative discovery works, why it took so long to confirm, and what still needs to happen before anyone can say with certainty that this candidate planet truly exists.

The host star's name, HD 137010, comes from the Henry Draper catalog, a massive stellar reference database used for nearly a century by astronomers around the world to identify and classify stars observed from Earth.

Why this discovery rests on a single transit detected in 2017

The story of HD 137010 b actually begins well before its official publication. A single transit — meaning a pass of the planet in front of its star causing a tiny, measurable dip in brightness — was detected as early as 2017 by NASA's K2 mission, an extension of the original Kepler program. At the time, this isolated signal wasn't enough to confirm a planet's existence with certainty.

It's precisely this kind of faint, ambiguous signal that the Planet Hunters project asks its volunteers to examine, betting on the human eye's ability to spot subtle patterns that automated algorithms can sometimes miss. It took several years and the attention of dedicated volunteers for this isolated 2017 signal to finally be brought back into the light and studied seriously.

This multi-year gap between raw data collection and in-depth analysis illustrates a often-overlooked aspect of space research: the sheer volume of accumulated information far outstrips humans' ability to process it in real time, creating a genuine reservoir of potential discoveries still waiting to be tapped, quietly sitting in digital archives until the right pair of eyes happens to look in the right place.

A platform open to any volunteer

The Planet Hunters project is part of a broader movement called citizen science, which invites the general public to take part directly in real scientific research. In practice, volunteers log onto an online platform where they examine stellar brightness curves, looking for slight, periodic dips that might betray a planet passing in front of its star.

This approach starts from a simple observation: the data archives accumulated by missions like Kepler and K2 are so vast that no team of professional researchers, however large, could examine them all alone. By mobilizing thousands of volunteers around the world, the project massively multiplies the available analytical capacity, turning an otherwise impossible workload into a manageable, distributed task.

Each volunteer receives simplified training to learn how to recognize the characteristic signals of a planetary transit, which makes participation accessible even without any prior scientific background — a founding principle of modern citizen science.

The platform's organizers also set up cross-verification systems, in which several volunteers independently examine the same data segment, considerably reducing the risk of error before a signal is passed on to a team of professional researchers for in-depth analysis.

Why the human eye still matters against algorithms

One might think that automated detection algorithms would be enough to catch every planetary transit hiding in the Kepler and K2 data. In reality, these algorithms are tuned to detect repetitive, sufficiently clear patterns, which sometimes makes them less effective against signals that are unique, faint, or slightly atypical, like the one associated with HD 137010 b.

What I particularly like about this story is the idea that human curiosity, even without specialized training, still holds real scientific value against the raw power of automated computation. It's this complementarity between the human eye and digital tools that pulled this 2017 signal out of obscurity.

This kind of collaboration has already led, in the past, to the discovery of several other candidate exoplanets, reinforcing the scientific legitimacy of the Planet Hunters project within the professional astronomy community.

This growing recognition has encouraged more researchers to openly collaborate with citizen-science platforms, now viewing these initiatives as a valuable complement to professional astronomy research rather than a mere educational gimmick.

The role of the team led by Alexander Venner

Once a signal is spotted by volunteers, it falls to a team of professional researchers to take over and rigorously analyze the data to determine whether the signal actually corresponds to a planet. In the case of HD 137010 b, it was the team led by Alexander Venner that carried out this in-depth analysis, culminating in the January 27, 2026 publication in The Astrophysical Journal Letters.

This process involves checking the signal's consistency with the known characteristics of the host star, ruling out alternative explanations such as instrumental noise or an unwanted companion star, and estimating the candidate planet's likely parameters, particularly its size and distance from its star.

The fact that the paper was accepted in such a well-regarded peer-reviewed journal speaks to the seriousness of the scientific work involved, even though the discovery is, at this stage, still presented as a candidate planet rather than an absolute confirmation. That careful wording matters, and readers of this guide should keep it in mind before assuming the case is fully closed.

This intermediate status, somewhere between simple hypothesis and scientific certainty, is common in astronomy and takes nothing away from the interest of the discovery: it simply reflects the caution required when dealing with signals as faint as the one associated with HD 137010 b.

Why further confirmation is still needed

In astronomy, a single detected transit generally isn't enough to definitively confirm an exoplanet's existence. Researchers need to observe several successive passes to precisely calculate the planet's orbital period and rule out any remaining doubt. That's why HD 137010 b now requires confirmation from other specialized telescopes, such as TESS or CHEOPS.

This confirmation step is crucial: it turns a solid hypothesis into an established scientific fact, recognized by the entire international community of astronomers specializing in the search for exoplanets. Skipping this step, however tempting it might be given the excitement around a new candidate, would undermine the credibility of the entire field.

The TESS and CHEOPS telescopes, both designed to monitor stellar brightness with great precision, are particularly well suited to this kind of follow-up verification, thanks to their ability to observe the same regions of the sky over long periods, patiently gathering the additional transits needed to settle the matter.

This methodical caution, which refuses to declare victory too soon, is in my view one of the great strengths of the scientific process, even if it can sometimes feel frustrating to a general public eager for certainty.

A size close to Earth's, but a very different climate

What makes HD 137010 b particularly worth attention is its size: slightly larger than Earth, it belongs to a category of rocky planets that astronomers are actively trying to understand better. Its nickname, "cold Earth," suggests a surface temperature that is likely very low, due to its distance from its host star.

Studying this type of planet helps researchers better understand the diversity of rocky worlds populating our galaxy, well beyond just the planets located in the so-called habitable zone where liquid water could exist on the surface. Not every interesting world needs to be hospitable to be scientifically valuable.

This diversity is valuable for refining theoretical models of planetary formation, by testing predictions against real cases observed around stars with varying characteristics. This mix of familiarity and strangeness — a planet almost like ours but likely frozen — is exactly the kind of detail that makes following exoplanet exploration so captivating.

What this discovery signals for future research

The eventual confirmation of HD 137010 b by the TESS or CHEOPS telescopes could open the door to further studies of its atmospheric composition, if this planet does turn out to have a detectable atmosphere. These follow-up analyses will likely require even more sensitive instruments, such as the James Webb Space Telescope.

Beyond this particular planet's case, this discovery illustrates a broader trend in modern space exploration: the growing complementarity between major institutional missions and the direct involvement of the general public in the scientific process. I find it encouraging to watch the line gradually blur between professional researchers and passionate amateurs, to the direct benefit of collective knowledge.

A concrete success story for citizen science

The story of HD 137010 b very concretely demonstrates the usefulness of citizen science in modern astronomical research. Without the attention of dedicated volunteers patiently examining brightness curves, this signal captured in 2017 would probably have stayed buried in NASA's vast K2 mission archives, never noticed or studied.

This case perfectly illustrates how individual curiosity, properly channeled through a well-designed platform like Planet Hunters, can lead to a scientific publication in a leading international journal — a path that would have seemed improbable just a few decades ago, back when amateur astronomy was mostly limited to direct observation of the night sky from one's own backyard. Today, the same enthusiasm can be channeled into a browser tab and a dataset instead of a backyard telescope, without losing any of its original wonder.

An invitation to take part in space discovery yourself

For anyone curious about astronomy, this story is a reminder that scientific discovery is no longer reserved for established experts alone. Platforms like Planet Hunters allow anyone to genuinely contribute to the exploration of our galaxy, by examining real data from prestigious space missions like Kepler.

This expanded accessibility of scientific research, driven by collaborative projects of this kind, could well multiply the number of similar discoveries in the years ahead, as more volunteers join these initiatives around the world. Sometimes all it takes is a simple account created on an online platform, a few minutes of attention, and a good dose of curiosity to, who knows, one day contribute to the next big exoplanet discovery. It's a small, quiet reminder that the universe is still full of secrets waiting for someone, anyone, to simply notice them.

By Maxime Marquette, columnist

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