Of the approximately 6,000 exoplanets we discovered, there is a significant number of the apparent habitable zones of their stars. Most are huge planets; Either gas giants like Jupiter and Saturn or ice giants like Uranus and Neptune. Could some of them have habitable exomoons?
There could be no life on the huge planet of our solar system. However, some of her moons have become the main goals in search of life. It leads to a natural question: Could huge exoplanets in habitable zones have other stars habitable moons?
Astronomers have only determined tempting references to exomooons, although their existence is practically guaranteed. The theory shows that the moon formation is a natural process. It is difficult to find exoplanets, even though we got used to it and it is even more difficult to find your moons.
Researchers from Hungary and the Netherlands wanted to investigate how exomoons could form away huge planets to get an insight into their existence. Her research is entitled “Grand Theft Moons: Formation of habitable moons around huge planets” and is published in astronomy and astrophysics. The main author is Zoltán-Ducs from the Hun-Ren Research Center for astronomy and geosciences.
“We want to examine in a phase in a phase in a phase that resembles the final assembly of planet formation,” the authors write. “We are looking for conditions for the formation of the largest moons with the highest possibility for circumference and examine whether the resulting moons can be habitable.”
It begins with circumferential discs, the rotating material collection that remains according to a planet. The researchers used simulations to determine which proportion of this material can successfully form moons. In this case, the researchers focused on the most massive moons.
This Alma picture from 2019 shows the circular planetary disc around exoplanet PDS 70C, the point-like source on the right. This was the first time that astronomers saw one of these hard drives, and the discovery confirmed theories about the formation of planets and moon. Photo credits: by Alma (ESO/Naoj/Nrao)/Benisty et al., CC of 4.0
“We have determined the proportion of the mass of the environmental planetary disc using numerical N-body simulations in moon embryos, in which mondembryos grow over embryo satellitesimal collisions,” the researchers write. They examined the panes around huge planets, on which 100 mondemryons with 1000 satellitesimal interact. The planets were 461 known giant exoplanets from an exoplanet database.
An habitable zone for planets depends on the outstanding radiation of the star. With enough energy, liquid water can exist on the surface of a planet in view of the correct atmospheric conditions and other factors. The formula is a little different for mondes. In our solar system, icy moons like Europe and Enceladus probably have liquid water under a frozen cap, but the heat comes from flood flexion. The researchers have included this heat in their simulations.
“In order to determine the habitability of the synthetic moons, we have calculated the star radiation and the river heating flow of this moon based on their orbital and physical parameters,” the authors write. “The global flow of energy on the moons can be significantly influenced by tidal heating, which comes from the flood energy department of the interactions between the planet and the moon,” they explain.
As our solar system shows, the tidal heating becomes clearer the further a moon comes from its star.
This figure from research shows the situation for a hypothetical moon that has tidal heating around the exoplanet HD 114386 B. The conservative HZ is limited by the outstanding greenhouse line and the maximum greenhouse line. Photo credits: dencs et al. 2025, A&A
The team's simulations included extensive hard drives in the last phase of moon formation. For the sake of simplicity, they only concerned rocky bodies and gas -free hard drives. “The slices consist of mondryons that are embedded in a swarm of satellitesimal, and the only force taken into account in the calculation is gravity,” they write. All objects – the star, the planet, the embryos and the satellitesimals – Gravital. The simulations enabled embryo embryo or embryo satellitesimal collisions, but not collisions between satellitesimals. This also included hot and cold hard drives as well as other factors such as the eccentricity and tendency of embryos and satellitesimals.
Since body reacted in the simulation, there were four different results.
In the first result, the objects combined and added their mass. In the second, the planet emphasizes the object. In the third, the body is affected by the star. In the fourth, the body is ejected from the system. Only the first result forms exomoons.
The simulation included two time scales: the number of planetary orbit lanes around the star and the number of orbits for the proto satellites in the circular planetary disc. The first is star-centered (SC) and the second is planet-centered (PC).
The first question concerns mass loss. Do the slices remain enough mass to form habitable moons? The researchers found that the entire circular planetary disc loses the mass over time. When some embryos become more massive, their disorders derive the mass from the window and reduce the entire embryo mass.
This illustration from research shows some of the simulation results. The entire available embryo mass decreases over time. The left control panel shows the star-centered time scale and the right field shows the planet-centered time scale. Both show “the development of the mondemryos and the protosate disks of 10 Jupiter mass host planets on a logarithmic time scale,” explain the researchers. Photo credits: dencs et al. 2025, A&A
The most important mass loss is when the exomoons are in cold slices within 1 au of the star, as panel A shows above. In this situation, the hard drive loses between 30% and 40% of its mass. Panel B shows that embryos lose the mass in the planet-centered simulation, but this is not that extreme. They keep more than 90% of their initial mass.
The simulations provide much more detailed, but the results show that exomoons form and should remain huge planets in circulatory tarpaulins. This despite the mass loss, the effects and the embryos that are absorbed by the star or planet.
With increasing star removal, the number of moons increases. However, their initial masses are smaller. When the mass of the exomoon rises, more of them are lost due to the love for death. “Due to these two factors, the highest moon formation efficiency for the planet, which circles in two star distances, is observed,” the authors write.
Headability is a question of its own, and the simulations had some interesting results.
Via an AU, the tidal heating system becomes the main heating source for habitable exomoon. The simulations also showed that the number of habitable exomoons dramatically decreases over two Au, since the habitable zone shrinks. “The optimal distance for habitability is between 1–2 au star routes,” the researchers explain.
They also found that the number of exomoons increases with increasing star removal. However, their masses are too small, which makes them uninhabitable.
“We examined the habitability of alleged analogous earth moons by 461 known Ries Exoplanets, which were selected by their mass,” wrote the researchers in their conclusion. “Our simulations show that moons with masses between Mars and Earth can form planets with masses that are about ten times Jupiter, and many of these moons could possibly be habitable with 1–2 au star removal.”
The study shows that when looking for habitability, we should expand our scope by more than just rocky, habitable zone exoplanets. We should start searching for habitable exomones in major distances from your stars. “These locations offer suitable goals for the discovery of habitable exomoons or exomoons in general,” the authors write.
Jupiters Moon Europe is far beyond the outstanding habitable zone, but it could be habitable due to the flood flexes. The same applies to exomoons. Photo credits: NASA
Astronomers had no great success in recognizing exomones, although there are several candidates. However, we can be about to be confirmed. A research team from astronomers used the JWST to examine Exomoon candidates, but has not yet published their results. The upcoming Plato mission of the ESA may also be able to recognize some exomoons.
