A set of recent data analyses from Kepler Space Telescope have set their sights on HD 137010b, a possible Earth-sized exoplanet that has earned the nickname of “Frozen ground“among the researchers. Despite sharing several key characteristics with our planet, everything points to it being a much colder world, with average temperatures far below those we know on Earth's surface.
Scientific interest has skyrocketed because this exoplanet candidate is located around a star similar to the Sun, relatively close in cosmic terms: about 146 light-years awayIts size, its orbit, and its possible position in the habitable zone Its system makes it one of the most promising worlds to study what a rocky planet similar to Earth might be like, but subjected to an extreme and permanent glacial climate.
An exoplanet almost identical in size and orbit
According to the works published in the journal The Astrophysical Journal Letters, HD 137010 b would be a rocky planet barely 6% larger than EarthThat is, practically the same size in astronomical terms. This proximity in dimensions leads many scientists to describe it as a “almost a twin” of Earth or a “cold twin”, although with important nuances.
Estimates of its movement around the star indicate that it completes an orbit around the 355 daysa period very close to an Earth year. This detail is significant: an orbital period so similar to ours suggests that the planet is at a distance comparable to that between the Earth and the Sun, reinforcing the comparison with our own world.
The HD 137010 b signal was obtained from a single transit detected during the Kepler's K2 extended missionDuring that transit, the planet's shadow took approximately 10 hours to cross the disc of your starThis is compared to the approximately 13 hours that Earth would take for a similar event. This duration, combined with precise orbital models, has allowed for a reasonably robust calculation of both the size and orbit of the candidate.
The fact that only one transit has been identified, however, requires maintaining the label of "candidate"For the scientific community to officially recognize HD 137010 b as a confirmed exoplanet, at least three well-measured transits that occur periodically will be necessary, something that is still pending.
In any case, current data already places this world in a prominent position within the catalog of Earth-like exoplanetsBoth its size and its year being almost identical to ours make it a priority target for future observations from Europe and the rest of the world.
A star similar to the Sun, but cooler and dimmer
The planet orbits the star HD 137010a whirlpool bath, K dwarf which shares several properties with the Sun, although it is somewhat cooler and less luminous. These types of stars, slightly redder, emit less energywhich has direct consequences on the climate of the planets that surround them.
According to the calculations presented by the NASA, HD 137010 b It receives less than a third of the light and heat that the Earth receives from the Sun. This energy difference is key to understanding why, despite its size and orbit being so similar to our planet's, its surface would be much colder.
The climate models of the international team led by Alexander Venner, researcher of Max Planck Institute for Astronomy and a doctoral candidate at the University of Southern Queensland, point to a average temperature close to -68 °CThis figure, slightly lower than the average temperature of Mars (around -65 °C), places HD 137010 b in the range of frozen worldswhere a large part of the surface could remain frozen almost permanently.
In NASA's own words, the surface of the candidate “it might not exceed -68 degrees Celsius”This estimate has led some specialists to define it as a possible “Frozen Earth” or “Super Snowball”, a planet where, without a suitable atmosphere, liquid water could only exist underground, trapped under thick layers of ice.
This combination of star similar to the Sun but fainterA planet with an orbit similar to Earth's and a much more extreme climate presents a very interesting scenario for studying how stellar luminosity and atmospheric composition influence the actual habitability of a terrestrial-type planet.
A possible "Frozen Earth" on the edge of the habitable zone
One of the most discussed aspects of the discovery is the position of HD 137010 b with respect to the habitable zone of its star. This band is the region around a star where, in principle, it could exist. liquid water on the surface of a planet, provided its atmosphere allows it.
The research team's calculations place this world very close to the outer edge of that habitable zone. Depending on how that boundary is defined, it has been estimated that there is around an 40% probability that the planet is located within the "conservative" habitable zone of its system, and a 51% probability that it is within an “optimistic” habitable zone, somewhat longer.
These figures, while striking, should be interpreted with caution: they also imply a comparable probability that the planet will fall outside that band in practice. habitable zone is not a clear boundarybut an estimated band that depends on many physical and chemical factors, including the composition and density of the atmosphere, the presence of greenhouse gases, and surface reflectivity.
Even so, the idea of a planet slightly larger than Earth, 146 light-years away, and with a year almost identical to oursLocated precisely in the area where liquid water could exist under the right conditions, it has generated considerable interest in the scientific community. It's not a "second Earth" per se, but it is a natural laboratory ideal for testing theoretical models of habitability.
In comparison with other known candidatesas the Kepler-186f, HD 137010 b has one important advantage: Its star is brighter and much closer from us. In fact, some researchers point out that it is located at a distance approximately four times closer than other similar exoplanets, which facilitates the possibility of obtaining more detailed data in future observation campaigns, also from European observatories.
The atmosphere, the great unknown for habitability
If there is one element that can tip the scales between a world perpetually frozen And a temperate planet is, without a doubt, its atmosphereIn the case of HD 137010 b, climate models point to a scenario highly dependent on the concentration of carbon dioxide and other greenhouse gases.
The team led by Alexander Venner argues that, under a atmosphere denser and richer in CO₂ than Earth'sThe planet could become a world with temperatures suitable for liquid water, and even a relatively temperate environment. In that case, we would be talking about a very interesting candidate for harboring some kind of potential habitability, even if it were very different from Earth's.
On the other hand, if HD 137010 b had a thin or inefficient atmosphere for trapping heat, the result would be a genuine “super snowball”Under this scenario, much of the surface would be covered by ice, with an extreme climate dominated by temperatures close to -68 °C and with liquid water relegated, at best, to deep layers under the ice.
So far, astronomers have not been able to directly measure the atmosphere of this candidate, nor confirm its composition. Unlike larger, hotter exoplanets, where the atmosphere can be studied more easily, in compact, cold worlds like this one the task is much more complex and requires very sensitive instruments.
In this context, HD 137010 b has become a target of high interest for future research. atmospheric characterizationThis will be achieved using both space telescopes and large ground-based facilities in Europe and other continents. Understanding whether it has a dense atmosphere, what gases it contains, and how it retains heat will be key to determining if this "cold twin" of Earth could ever be habitable in any way.
Confirmation pending and next steps from NASA and ESA
Despite the hype, experts insist that, for now, HD 137010 b remains a candidate exoplanetThe finding is based on a single transit detected in the Kepler archives, and the usual scientific standard requires observing at least three periodic transits to consider the existence of a new world confirmed.
The practical problem is that, with an orbital period of around 355 daysThese transits occur very infrequently. Detecting the slight dip in the star's brightness again as the planet passes in front of it will require a lot of patience and prolonged observation campaignsSomething that both NASA and the European Space Agency already have in mind.
Among the tools planned for this task, the satellite stands out. TESS NASA's Transiting Exoplanet Survey Satellite and the European telescope CHEOPS (Characterising Exoplanet Satellite) ESABoth instruments are designed, among other things, to study planetary transits with great precision and could provide the necessary data for confirm the existence of HD 137010 by refining its orbital parameters.
If the transit can be observed again, it will be possible to adjust your position more accurately. size, orbital period and distance to the starand open the door to future research on its atmosphere using other techniques, such as spectroscopyFor the European and Spanish astronomical community, these types of nearby and potentially habitable targets have become a priority in exoplanet exploration.
Meanwhile, the possibility of physically traveling to this exoplanet remains completely out of reach. Even by traveling to current space speedsThe journey to a system located 146 light-years away would take tens of thousands of years. For now, the only realistic option is to continue. observing it from a distance, gradually refining the data obtained from its star and the faint trace of its transit.
Overall, HD 137010 b is shaping up to be one of the most interesting Earth-like exoplanets Discovered to date: a rocky world almost our size, which completes a year very similar to Earth's around a Sun-like star, but exposed to an extreme climate that could turn it into a true "frozen Earth." Although it is still pending confirmation and its atmosphere remains a mystery, this candidate encapsulates many of the current challenges in the search for potentially habitable planets and shows how, even by reviewing data from completed missions, clues continue to emerge about worlds that, while not an exact copy of Earth, help us better understand what truly makes a planet habitable.
