A planet nearly the same size as Earth has been found 72 light-years from Earth
(ORDO NEWS) — We’ve just discovered an exoplanet almost the size of Earth that orbits a tiny star just a short distance away.
It’s called K2-415b, and its similarities (and differences) to our own home world may shed some light on how Earth-like planets form and develop differently in systems very different from ours.
“Small planets around M dwarfs are a good laboratory for studying atmospheric diversity. rocky planets and the conditions under which a habitable terrestrial planet can exist,” writes an international team of astronomers led by Teruyuki Hirano from the Astrobiological Center in Japan.
“One of the lowest-mass stars known, K2-415, which hosts an Earth-sized transit planet, will be an interesting target for further observations, including additional radial velocity monitoring and transit spectroscopy.”
The study has been accepted for publication in The Astronomical Journal and is available on the arXiv preprint server.
The M The Elkway Galaxy is a big place with many interesting worlds, but so far it has eluded one of the biggest questions humanity has ever asked: why are we here?
And not only why, but also how, and why this planet, and is there anywhere else where life could potentially arise?
Since the Earth is the only place in the universe where we know for sure that life exists, one of the tools that could help provide answers is a population of Earth-like exoplanets.
Similar in size, composition, temperature, mass; perhaps even the architecture of the planetary system.
The best population of exoplanets to start this exploration are small Earth-sized worlds orbiting small stars relatively close together in such a way that they transit or pass between us and the star.
This is because they are the best candidates for atmospheric characterization.
When an exoplanet passes in front of a star, some of the star’s light passes through the atmosphere, while some of the wavelengths in the spectrum are absorbed. or enhanced by elements in the atmosphere.
Around smaller, dimmer, cooler stars like red dwarfs, the habitable temperature zone is much closer to the star than around a star like the Sun.
This means that the orbital period is shorter, so many passes can be recorded and summed to amplify the spectrum data. And, obviously, closer stars will appear brighter, making such observations easier.
Small exoplanets, however, are more difficult to find than large ones.
Only 14 exoplanets, 1.25 times smaller than Earth’s, have been found orbiting red dwarfs within 100 light-years of the solar system, including all 7 worlds in the TRAPPIST-1 system.
This is an example where there are never too many data points, and Hirano and his colleagues seem to have found the fool.
Exoplanet K2-415b is 1.015 times the radius of Earth and orbits one of the smallest red dwarfs discovered, hosting an Earth-sized world. The mass of the star K2-415 is only 16 percent of the mass of the Sun.
The exoplanet was first discovered in data from the now retired Kepler planetary search telescope in 2017. data from Kepler’s successor, TESS.
The researchers continued their observations, taking infrared observations to see if they could detect a slight “wobble” in the star’s motion as it twitches slightly on the spot due to the exoplanet’s gravity.
This set of data revealed the existence of the world, as well as its characteristics. The amount of starlight blocked by the passage of an exoplanet can be used to calculate the planetary radius. The magnitude of the vibration determines its mass.
These two parameters can be combined to calculate the density of an exoplanet. And, of course, the frequency of transits reveals the orbital period of the exoplanet.
This is where K2-415b begins to seriously differ from Earth. Although the exoplanet is the size of Earth, its mass is much higher, about three times that of Earth. This means that K2-415b is also denser than Earth.
And it is much closer to its star: its orbital period is only four days.
It’s true that a red dwarf’s habitable zone could be much closer than the Sun’s habitable zone, with orbits measured in days rather than months, but that’s too close for comfort, even for a red dwarf.
True, quite a bit. K2-415b is just outside the edge of K2-415’s habitable zone. This may mean that he still has the atmosphere to explore.
In the solar system, Venus is just inside the habitable zone, and its atmosphere is a dense and intriguing horror show.
It is also possible that K2-415 is a multi-planet system; this raises the possibility that there is currently an undetected exoplanet in the star’s habitable zone.
Therefore, we are unlikely to find signs of life on K2-415b. But the system is an excellent target for describing an exoplanet’s atmosphere and for subsequent exploration in search of hidden, potentially habitable worlds.
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