The planet is in the wrong place.

“LHS 1903 is a small red M-dwarf star that is cooler and shines less brightly than our Sun. Scientists used telescopes in space and on Earth to discover four planets orbiting LHS 1903. With those telescopes, they classified the three closest planets to the star as the innermost being rocky, and the two that follow it as gas giants. Credit: ESA” (ScitechDaily, Astronomers Stunned by Rocky Planet in the Wrong Place)

“Scientists have identified a rocky outer planet in a system where a gas giant was expected. The discovery challenges traditional models and supports the idea that planets may form one by one in changing environments.” (ScitechDaily, Astronomers Stunned by Rocky Planet in the Wrong Place)

Could xxoplanet LHS 1903 e be a rogue planet that a red dwarf HS 1903 captured? This explains the exoplanet’s wrong trajectory. 

The exoplanet  LHS 1903 e is a rocky world near a red dwarf star LHS 1903. This planet is extraordinary. Because of its trajectory. The LHS 1903 has a planetary system, where the closest exoplanet is a rocky world. Then there will be two scaled-down versions of Neptune. So, those planets are gas-rich. But then. The last known planet, LHS 1903 e. 

It is again a rocky world. This means that the LHS 1903 e doesn’t follow the rule about the order of the planets. So, this “wrong position”. Causes an idea. This exoplanet could have originated around some other star. And then that star lost this planet. Maybe the nova or supernova eruption kicked that exoplanet LHC 1903 e from its trajectory. 

So, could the origin of the dwarf planet Pluto in our solar system be a rogue planet? 

The hypothesis about the rogue planet that the star captured can explain some details about the dwarf planet Pluto and its moon, Charon. There are several theories about the origin of Pluto. The first one is that Pluto’s origin was as the moon of Uranus or Neptune. The one other explanation . About Pluto. It could be. That Pluto. It was. Some kind of rogue asteroid. Or a dwarf planet. That our solar system captured.

https://scitechdaily.com/astronomers-stunned-by-rocky-planet-in-the-wrong-place/

The exoplanet GJ 215 c. Can host lifeforms in the future.

“An international team of scientists dubbed the exoplanet, named GJ 251 c, a “super-Earth” as data suggest it has a rocky composition similar to Earth and is almost four times as massive. Credit: Illustration by University of California, Irvine.” (ScitechDaily, Astronomers Discover Potentially Habitable “Super-Earth” Just 18 Light-Years Away)

The new exoplanet. From 18 ly. away from Earth, can have liquid water on its surface. The exoplanet  GJ (Gliese) 251 c orbits the M-class star in a potentially habitable zone. The  GJ 251 c is a massive super-Earth that orbits the star GJ 215. That star has a spectral classification of M3V, and its age is about 6,6 GYR (Gigayears). Or, a simpler saying. 6,6 billion years. This means that. This M3V is still in its flare period. And there might not be lifeforms. On that exoplanet. Life formation begins after the flare period. The GJ 215 has two exoplanets. GJ 215b, whose mass is ≥ 3.85+0.35−0.33 Earth masses. And GJ 215 c, whose mass is ≥3.84±0.75 Earth masses. 

This means lifeforms start to advance later than on planets. That orbit the Sun (G2) type stars. But otherwise, the red dwarfs can live Tens to hundreds of billions of years. That means life has more time to advance on those planets than on planets that orbit G2V-type stars. In the future. The GJ215c might host. 

Even intelligent lifeforms.  But today, its star is too unstable for that. Those hypothetical civilizations require more mature stars. The problem with the red dwarf planets and technocivilization. This is how long radioactive isotopes can exist on those planets. There is a possibility that some of those planets run out of their fissile material. 

And their cores start to cool. That cooling process destroys the planet’s magnetic field. Those super-Earths that orbit M-type stars give a hint. About the possibility of lifeforms. Those super-Earths with a dense atmosphere can host life, but the star must be mature enough that it has ended its flare period. Those flares that the young red dwarfs create. It can raise. Those planets' temperatures. Into thousands of degrees. 

The atmosphere of those locked planets smooths their atmosphere’s temperature. All red dwarf-star planets that are in the habitable zone are locked. The tidal forces from the star lock the planet into position. There, it turns the same side to that star all the time. There is forever night in the side that is away from its star. And the other side is burning hot. The water and atmosphere, along with clouds, can smooth that effect. But that requires. The star will not create. It's flares anymore. 

https://science.nasa.gov/exoplanet-catalog/gj-251-c/

https://scitechdaily.com/astronomers-discover-potentially-habitable-super-earth-just-18-light-years-away/

https://en.wikipedia.org/wiki/Gliese_251

https://en.wikipedia.org/wiki/Stellar_classification

https://en.wikipedia.org/wiki/Sun

The Earth-size exoplanet GJ 1132 b has no atmosphere.

The Earth-size exoplanet GJ 1132 b has no atmosphere.

"Artist’s impression of exoplanet GJ 1132 b and its host M-dwarf star. Credit: Dana Berry, Skyworks Digital, CfA"

"JWST confirms GJ 1132 b lacks an atmosphere. This challenges the habitability of planets around M-dwarfs."

(ScitechDaily, JWST Solves the Mystery: Earth-Like Planet GJ 1132 B Has No Atmosphere)

The Earth-size exoplanet GJ 1132 b has no atmosphere. And that causes some kind of re-estimation of the habitability of the M-type stars. Those M-type stars have violent eruptions that can raise the temperatures of their entire solar systems. Those solar systems are always quite small, and if the planet is in the habitable zone, that means it's locked because of tidal forces. 

The GJ 1132 b is almost a so-called hot Earth. That means there might not be a lifeform. But another question is, can we escalate those observations to other red dwarfs? Red dwarfs, or M-spectral class stars, are not all similar. Some of them are more active than others. 

If the planet is very young, that can explain the lack of atmosphere. The volcanic activity can explain the smoke or fog around the exoplanet GJ 1132 b. Or that slightly larger than Earth exoplanet can pull solar wind from its star, GJ 1132, an M4-type red dwarf, around it. This means the planet’s gravity pulls the gas that the red dwarf sends around it. And if the GJ 1132 b has a magnetosphere that pulls plasma around it. This means G J1132 b borrows its atmosphere from the star GJ 1132. 

The M-6 spectral Class star Proxima Centauri is under the influence of Alpha Centauri, and that means Alpha Centauri A and B’s star wind can affect Proxima Centauri and blow its atmosphere away. Or the gravitational effect of the bigger parts of this triple star system’s larger participants. Can pull the Proxima Centauri atmosphere off. The reaction can go like this. 

"Artist’s impression of GJ 1132 b – which now should be updated given its definitive lack of atmosphere. Credit: NASA/JPL-Caltech/Robert Hurt" (ScitechDaily, JWST Solves the Mystery: Earth-Like Planet GJ 1132 B Has No Atmosphere)

"Comparison of best-fit size of the exoplanet GJ 1132 b with the Solar System planet Earth, as reported in the Open Exoplanet Catalogue of 2015-11-14.  Open Exoplanet Catalogue (2015-11-14). Retrieved on 2015-11-14." (Wikipedia, GJ 1132 b)

Radiation from a binary star made the red dwarf shine brighter. That made M-star blow its atmosphere larger. Then the gravity and solar wind blew that material away. Some M-stars are more active than others. There are many variables that determine if a planet can have an atmosphere. If the red dwarf is very young, that means it's more active than older red dwarfs. Another thing is this. Planet formation is similar around red dwarfs as it was in our solar system. The planet that forms around M-type stars must have time to freeze.

The difference between M-stars and spectral class G-stars is that red dwarfs formed from a more mature nebula than G-stars. Those interplanetary nebulae formed when stars exploded as novae and supernovae. That means there are more heavy elements in the red dwarf system than in the G-type star systems. That means, there could also be more radioactive isotopes in those planets than in G-type stars’ planets. This could cause an effect. That some of those rocky planets are hotter than they should be. But that is hard to prove. 

The red dwarf could also form in a binary star system when the star’s heliospheres touch each other. That can cause the small star forms in that whirl. There is also a possibility that a red dwarf travels around space, and some bigger star traps it into its gravity field. The red dwarf can also steal planets from bigger stars' solar systems. If they travel close to the distant planets of the larger stars, those red dwarfs can take those planets to orbit around themselves. 

They can also trap rogue planets in their gravity field. There is a possibility that the Proxima Centauri planets originally orbited Alpha Centauri. Then Proxima trapped them in orbit around itself. 

https://scitechdaily.com/jwst-solves-the-mystery-earth-like-planet-gj-1132-b-has-no-atmosphere/

https://en.wikipedia.org/wiki/GJ_1132_b

https://en.wikipedia.org/wiki/GJ_1132

https://en.wikipedia.org/wiki/Proxima_Centauri

An Earth-size exoplanet is in a death spiral in its solar system.

   An Earth-size exoplanet is in a death spiral in its solar system. 

"This artist’s illustration shows an Ultra-Short Period (USP) planet orbiting its star. A newly-discovered USP runs the risk of either being torn to pieces by its star or being sucked in and destroyed. Credit: NASA, ESA, and A. Schaller (for STScI)" (ScitechDaily, This Earth-Sized Exoplanet Is Racing Toward Its Own Destruction)

Nothing is forever in the universe. 

Researchers noticed that the K-type orange star’s TOI-2431b is closing its star. And that earth-size exoplanet is going to its destruction. That exoplanet is an example that if a planet orbits too close to a small star can cause a situation. The planet starts to fall into the star. The small stars have one problem. Their gravity is weak. That means they cannot stabilize their solar system in the same way as bigger stars. In small star systems, the smaller objects can have a bigger effect than in the larger stars’ solar systems. An interesting detail is that TOI-2431 is a K-type orange star. But maybe those destructions are more common in the universe than nobody expected. 

In the universe, most stars are red dwarfs. Those stars are very light, and that means their solar systems are smaller than our solar system. Those stars’ weak gravity means that red dwarfs’ planets must orbit very close to their stars. The close distance causes danger than when something like a meteorite. That comes out from those solar systems pushes their planet to a red dwarf. 

And that can cause a situation where the planet impacts the red dwarf. Those planets can follow a spiral trajectory, and sooner or later. Those planets will change their orbital period into ultra-short-period planets (USP). Then the tidal forces from a red dwarf can rip them into pieces. Or they impact the host star. This is the thing in all gravitational centers in the universe. 

The red dwarf and its planetary system can pull other objects to them from a long distance. That means the lonely red dwarfs are more at risk of facing those cosmic intruders than red dwarfs that are near some larger stars. The lonely red dwarf pulls objects straight to its system. But in cases like Proxima Centauri, the dominating binary star can pull those particles into its solar system. And that protects Proxima’s planets from cosmic impacts. 

"This figure from the research shows that among USP planets, TOI-2431 b has the shortest timescale until tidal disruption of ∼31 Myr. Credit: Tas et al. 2025 A&A" (ScitechDaily, This Earth-Sized Exoplanet Is Racing Toward Its Own Destruction)

The reason why red dwarf systems are a riskier place for cosmic impacts than our solar system is this. Those solar systems are very small. These planets are closer to each other than in our solar system. The red dwarf is more dominant than the Sun. When an object like a comet or asteroid comes to our solar system from outside the Kuiper Belt, that object must travel longer time. There are four massive gas giants on its journey, and they can pull that intruder into their gravity fields. In small solar systems, planets are closer to their sun. There might not be dominant planets like Jupiter. 

The object comes straight to the system, and those giant gas planets do not have the same time to curve the cosmic visitor's trajectory as Jupiter and other gas planets have in our solar system.  When those cosmic intruders come to the solar system that fits inside Mercury’s trajectory, that thing has no time to change its course.  In those small solar systems, the horizontal gravity effect has no time to affect the trajectories of high-speed objects. 

Because planets are closer to the cosmic intruder, they have a higher chance of hitting it than in our solar system. The main thing is that. The red dwarf is lighter than the sun. It cannot stabilize its solar system same way as the Sun. And if there are gas giants and rocky planets in the same red dwarf solar system, the rocky planet is on the opposite side of the red dwarf to the Earth-sized exoplanet. Then the common gravity effect of those objects can pull one or more smaller planets from their trajectory. That can cause a situation where those planets fall into the red dwarf. 

Same way. The rogue planet that passes the red dwarf can pull those planets into that star. Things like ion beams or interstellar shockwaves can push those small stars’ planets out of their trajectory. Red dwarf systems are not as stable as larger stars’ solar systems. Those planets are orbiting closer to the lightweight star. And that means the smaller things in those systems can have a bigger effect than in the larger stars’ solar systems. If a Jupiter-size planet goes behind the sun, that thing has a smaller effect on Earth than if a similar planet goes behind the red dwarf that Earth-size exoplanets orbit. 

Rogue planets that travel all around the universe, out from their solar systems, can pull other particles into them. And that can cause multiple impacts to those planets that escaped from their solar systems. 

https://scitechdaily.com/this-earth-sized-exoplanet-is-racing-toward-its-own-destruction/

https://en.wikipedia.org/wiki/TOI-2431_b

https://en.wikipedia.org/wiki/Ultra-short_period_planet

Telescopes found a gas giant candidate 4 light-years away.

   Telescopes found a gas giant candidate 4 light-years away. 

"This artist's concept shows what the gas giant orbiting Alpha Centauri A could look like. Observations of the triple-star system Alpha Centauri using NASA's James Webb Space Telescope indicate the potential gas giant, about the mass of Saturn, orbits the star by about two times the distance between the sun and Earth. In this concept, Alpha Centauri A is depicted at the upper left of the planet, while the other sun-like star in the system, Alpha Centauri B, is at the upper right. Our sun is shown as a small dot of light between those two stars. Credit: : NASA, ESA, CSA, STScI, R. Hurt (Caltech/IPAC)" (Phys.org, Evidence found for planet around closest sun-like star)

"Now, Webb's observations from its Mid-Infrared Instrument (MIRI) are providing the strongest evidence to date of a gas giant planet orbiting in the habitable zone of Alpha Centauri A. (The MIRI instrument was developed in part by the Jet Propulsion Laboratory [JPL], which is managed by Caltech for NASA). The habitable zone is the region around a star where temperatures could be right for liquid water to pool on a planet's surface." (Phys.org, Evidence found for planet around closest sun-like star)

The new Jupiter- or Saturn-type gas giant orbits Alpha Centauri A. That gas giant is interesting because its location is in the triple-star system. And another interesting thing is that. The exoplanet orbits the Alpha Centauri primary system. We have known for a while that there are two confirmed exoplanets and one exoplanet candidate around Proxima Centauri. But that new gas giant is something else. It orbits Alpha Centauri A, which is likely to be our Sun. And that raises the possibility of finding extraterrestrial life forms from the Alpha Centauri system.  

The fact is that we might not find exocivilization around those stars. And if there are no intelligent lifeforms on some planet, that makes it hard to detect those alien organisms. If those organisms are primitive caryotes, it is very hard to separate their metabolic products from those of other chemical reactions. If the planet is a so-called water world, its entire surface is covered by oceans. And those very primitive algae and bacteria can live in those oceans. 

The first organisms lived in the Earth's oceans. If alien prokaryotes are like the first prokaryotes that lived in the oceans, the atmosphere of the planet can be very hostile. There are many things. That determines whether the water world can support life. If the atmosphere is dense and the gravity is high, that means water cannot boil. 

There are creatures on Earth that can live in very high-temperature water near so-called hydrothermal vents. Those so-called black smokers are a volcanic eruption hole. 

"In contrast to the approximately 2 °C (36 °F) ambient water temperature at these depths, water emerges from these vents at temperatures ranging from 60 °C (140 °F)[6] up to as high as 464 °C (867 °F). Due to the high hydrostatic pressure at these depths, water may exist in either its liquid form or as a supercritical fluid at such temperatures. The critical point of (pure) water is 375 °C (707 °F) at a pressure of 218 atmospheres."  (Wikipedia, hydrothermal vent) 

"The hydrothermal vents are recognized as a type of chemosynthetic based ecosystems (CBE) where primary productivity is fuelled by chemical compounds as energy sources instead of light (chemoautotrophy). Hydrothermal vent communities are able to sustain such vast amounts of life because vent organisms depend on chemosynthetic bacteria for food. " (Wikipedia, hydrothermal vent) 

"The water from the hydrothermal vent is rich in dissolved minerals and supports a large population of chemoautotrophic bacteria. These bacteria use sulfur compounds, particularly hydrogen sulfide, a chemical highly toxic to most known organisms, to produce organic material through the process of chemosynthesis." (Wikipedia, hydrothermal vent) 

The water can be at a very high temperature and support life, because it's in supercritical form. The high pressure and high gravity prevent the water from boiling. There are no bubbles in supercritical water. And that helps organisms survive near black smokers. 

We could see life's building blocks and things like carbon dioxide. But we would not see things like algae from the water planet. Another thing is that there may be no lifeforms in the gas giant's atmosphere. 

However, there is a possibility that those gas giants may have moons similar to Jupiter's Europa. Low gravity and low gas pressure can keep water liquid in low temperatures. So the habitable zone can be far different from what we used to think. Intelligent lifeforms probably don't form on those moons. But primitive algae and bacteria can live in those icy worlds. 

The water moon can host lifeforms like bacteria and algae. But those things are not easy to detect. The planetary models that astronomers use are made using our own solar system as a model. All gas giants in our solar system have moons. So maybe all other gas giants that orbit other than red dwarfs can have moons, or dwarf planets orbiting them. 

https://www.astronomy.com/science/alpha-centauri-planet/

https://www.jpl.nasa.gov/news/nasas-webb-finds-new-evidence-for-planet-around-closest-solar-twin/

https://phys.org/news/2025-08-evidence-planet-closest-sun-star.html

https://en.wikipedia.org/wiki/Hydrothermal_vent

https://en.wikipedia.org/wiki/Proxima_Centauri

https://en.wikipedia.org/wiki/Proxima_Centauri_d

https://en.wikipedia.org/wiki/Proxima_Centauri_b

https://en.wikipedia.org/wiki/Proxima_Centauri_c

New Earth-mass exoplanet found near red dwarf.

"Artist’s conception of a rocky Earth-mass exoplanet like Wolf 1069 b orbiting a red dwarf star. If the planet had retained its atmosphere, chances are high that it would feature liquid water and habitable conditions over a wide area of its dayside. Credit: NASA/Ames Research Center/Daniel Rutter" (ScitechDaily.com/Astronomers Discover Earth-Size Planet – Promising Target in the Search for Alien Life)

The new exoplanet Wolf 1069 b is a giant Earth-mass rocky planet. The new exoplanet orbits red dwarf Wolf 1069 in the habitable zone. The location of Wolf 1069 is in the Cygnus constellation. The surface temperature of that star is 3158±54K or 2884,85±54C. 

That means this M5 spectral class red dwarf is a very small, and cold object if we compare it with the Sun. And, its solar system is also small. 

The distance between Earth and Wolf 1069 is 31.229 ly. So, it's quite near to us. The exoplanet trajectory fits in Mercury's trajectory. If we want to compare that Wolf 1069 system with our solar system. But the star is much colder than the sun. And that means the shell of that planet is not melting to lava. 

And that means there could be liquid water. The planet itself is locked. So there are no similar lifeforms that exist on Earth. The problem is that the dayside of those locked planets is extremely hot.  

The nightside of locked exoplanets is very cold.  Powerful winds are blowing on its surface. And those winds are stabilizing temperature on locked planets. That means that liquid water is possible on those planets.

Many other variables determine if liquid water is possible. The one thing is the atmosphere. First, the planet must have an atmosphere where liquid water can exist on it. 

Then the gravitational field's strength must be right. If the gravitational field is too strong it pulls water to ice. If the gravitational field is too weak. Water boils in low temperatures. 

So if the planet's gravitational field is strong, water can stay liquid on hotter planets. But that means the planet must stay closer to its star than a weak gravitational planet. 

Same way weak gravity means that the melting point of water is lower. That means on the planets which gravitational fields water can stay liquid in a lower atmosphere. 

Water itself doesn't guarantee that the planet can host life. If the chemical environment doesn't contain elements that amino acids include the lifeforms cannot form on that planet.  Also if water boils at a low temperature that can affect the ability to form proteins. High temperatures can also affect the ability to form complicated molecules. The terms "lifeforms" and "intelligent lifeforms" are not synonyms. 

Things like amoebas and diatoms are life forms. But they are not intelligent lifeforms. Intelligent lifeforms require time to advance. An intelligent lifeform doesn't mean. That it can build rockets and airplanes immediately. 

Culture and technology require time to develop. And, of course, species require motivation to create technology. So even if some planet hosts intelligent lifeforms, those lifeforms would not necessarily have the technology. So, technically advanced lifeforms and intelligent lifeforms are not synonyms either. 

By the way, if we are thinking about intelligent creatures that could live on locked planets. Those creatures must live in the nightside of those planets. That means those creatures would have big eyes. And they would like to be in the night rather than dayside. So that is one remarkable thought that so-called "grey men" are forming in my mind.

Living at night or in low-level light requires big eyes. And those creatures would be very sensitive to sunlight. 

https://scitechdaily.com/astronomers-discover-earth-size-planet-promising-target-in-the-search-for-alien-life/

https://en.wikipedia.org/wiki/Wolf_1069

https://astronomyandtechnology.blogspot.com/

The JWST confirmed the existence of an Earth-size exoplanet at the border of the habitable zone.

Artist's illustration of exoplanet LHS 475 b

The existence of an Earth-size exoplanet in a distant solar system is a remarkable thing. The new small rocky planet. Called LHS 475b orbits its sun only in two days. The LHS 475b's atmosphere is mostly carbon dioxide. 

And that means the temperature on that planet's dayside is hot. As you might guess the LHS 475 b orbits red dwarf star LHS 475. The surface temperature of this planet is 3312±157 K or about 3039 C. 

That means LHS 475 b is dead and unable to host life. But that exoplanet is one of the most incredible things that the JWST telescope found. The ability to see that kind of exoplanet is a big change. The problem is that most confirmed exoplanets are orbiting red dwarfs. So planets are orbiting those stars very close. And tidal forces lock them in one direction. Their dayside is very hot. 

"A flat line in a transmission spectrum, like this one, can be exciting – it can tell us a lot about the planet. Researchers used NASA’s James Webb Space Telescope’s Near-Infrared Spectrograph (NIRSpec) to observe exoplanet LHS 475 b. As this spectrum shows, Webb did not observe a detectable quantity of any element or molecule. Common signatures in a hydrogen-dominated atmosphere, for example, would indicate a light, gaseous atmosphere. Those elements were not detected in LHS 475 b’s spectrum." (scitechDaily.com/A New Frontier: NASA’s Webb Space Telescope Confirms Existence of Earth-Sized Rocky Exoplanet!)

Above: Transit light curve of exoplanet LHS 475 b

And there are massive monsoon winds around the planet. That means those winds will stabilize the temperature. Things like gravitation and red dwarfs activity are affecting the planet's ability to keep liquid water. Weak gravitation means that the water can be liquid for a longer distance than in heavy gravitation. 

The winds would be stronger in weak gravitation. So there could be deadly sandstorms in weak gravitational planets, but otherwise, water would be liquid at a longer distance. 

So those weak gravitational planets could form intelligent space civilizations even if they orbit red dwarfs. And if those civilizations exist those aliens would be thin. And they might have a big head. Big eyes are making it possible to see in low-light environments. 

They would not need strong muscles in weak gravitation. So that means they might be delicate even if they look like humans. But that is only one version of the cosmological way to think about the hypothetical alien race. 

https://scitechdaily.com/a-new-frontier-nasas-webb-space-telescope-confirms-existence-of-earth-sized-rocky-exoplanet/

https://astronomyandtechnology.blogspot.com/

Some planets are unlike any planet in our solar system.

The exoplanet Kepler 138d is a water world. The giant ocean and water vapor cover the entire planet. And there is the large solid nucleus and that planet's mass is 1,17 times Earth's. The size of that exoplanet is larger than Earth's. 

Its classification is "super earth".  But in the case of Kepler 138 d that classification comes from its size. Not from its gravitation. The mass of Kepler 138 d is, depending on sources 0,6-1,17 Earth. 

A planet's mass determines its gravitational field and whether it is larger than Earth. But if the mass of the planet is the same or less, it means that there are fewer heavy elements than on Earth. If a planet has a greater mass than Earth but is smaller in size.

This tells us that there are more heavy elements than there are on Earth. In other words, a planet may be smaller in size than Earth, but its gravitational field may be stronger than Earth's.

So because the mass of the Kepler 138d is almost similar to Earth that makes this planet interesting. There is some conflict between the sources that determine the mass of Kepler 138d. Wikipedia tells. That the mass of Kepler 138d is 1,17 Earth mass(1). 

But NASA's database tells. That the mass of Kepler 138d is 0,64 Earths. (2)If the last of those numbers is true. That means there are not so many heavy elements on that planet as on Earth. 

(1) https://en.wikipedia.org/wiki/Kepler-138

(2)https://exoplanets.nasa.gov/exoplanet-catalog/1557/kepler-138-d/

But its size is bigger which means the solid core of that planet is not formed of at least very heavy elements. There are fewer heavy elements than on Earth. And that makes Kepler 138d very interesting. The mass of the exoplanets is the thing that makes them similar to Earth, not the size. 

So that means the planet is very unlike Earth. The Kepler 136 B orbits the star Kepler 138 in 23,1 days. And the star Kepler 138 is an M-type star. Which means its surface temperature is about 2400–3700 Kelvin. So that star is very cold. And that means the Kepler 138 d has a level in its ocean where fish-type habitats could exist and live. 

The thing that makes Kepler 136B interesting is that this very hot exoplanet might have some kind of life forms. The extremely high temperature doesn't mean that the water can vaporize on that planet because there is so much water. There is high-pressure water inside the giant ocean. And clouds are cooling the surface of that strange world. 

https://exoplanets.nasa.gov/exoplanet-catalog/1557/kepler-138-d/

https://scitechdaily.com/water-worlds-astronomers-discover-that-two-exoplanets-are-unlike-any-planets-in-our-solar-system/

https://en.wikipedia.org/wiki/Stellar_classification