extrasolar planets

K2-120 b: Super Earth Discovery

Exploring K2-120 b: A Super Earth Exoplanet Beyond Our Solar System

The universe is vast, and our understanding of it continues to expand with every new discovery. Among the many intriguing exoplanets uncovered in recent years, K2-120 b stands out as a fascinating example of the diverse planetary bodies that exist in our galaxy. This article delves into the features of K2-120 b, a Super Earth exoplanet located more than 900 light-years away, and explores the scientific significance of its discovery.

Discovery of K2-120 b

K2-120 b was first identified in 2017, a part of NASA’s extended Kepler mission known as K2. The K2 mission aimed to discover exoplanets beyond our solar system by observing the brightness variations of stars. When a planet passes in front of its host star, it causes a temporary dimming of the star’s light, a phenomenon known as a transit. This transit is what allowed astronomers to detect K2-120 b.

The planet is situated approximately 944 light-years away from Earth, within the constellation Lyra, a region that is rich in stellar activity and the location of many other intriguing exoplanets. The discovery of K2-120 b was made possible through the use of the transit method, which has been one of the most successful techniques in identifying exoplanets.

The Type and Characteristics of K2-120 b

K2-120 b is classified as a Super Earth, a type of exoplanet that is larger than Earth but smaller than Uranus or Neptune. The term “Super Earth” refers to planets with a mass higher than Earth’s, typically in the range of 1 to 10 Earth masses. Super Earths have become a focus of exoplanet research because they could potentially harbor conditions suitable for life.

Mass and Radius

K2-120 b has a mass that is approximately 4.7 times greater than Earth’s. This places it in the category of Super Earths with substantial gravitational pull. The planet’s radius is also larger than Earth’s, measuring about 2.01 times the radius of our planet. These characteristics suggest that K2-120 b is likely composed of a combination of rock and gas, though its specific composition remains unknown.

The larger mass and radius of K2-120 b indicate that it has a significantly higher surface gravity than Earth. This could mean a more extreme environment, with potentially higher pressures and temperatures, depending on the planet’s atmospheric composition.

Orbital Properties

One of the most remarkable features of K2-120 b is its proximity to its host star. The planet orbits very close to its star, with an orbital radius of just 0.078 AU (astronomical units). This places K2-120 b much closer to its star than Earth is to the Sun. As a result, the planet experiences intense heat, making it unlikely to support life as we know it. The orbital period of K2-120 b is incredibly short, taking only about 0.0263 Earth years (roughly 9.6 Earth days) to complete one orbit.

Despite its close proximity to its star, K2-120 b does not have an extremely circular orbit. The planet’s eccentricity is measured at 0.14, which indicates that its orbit is slightly elliptical. This means that the distance between K2-120 b and its host star varies over the course of its orbit, potentially influencing the planet’s climate and atmospheric conditions.

The Host Star and Stellar Characteristics

K2-120 b orbits a star that is located in the main sequence of stellar evolution, meaning it is in a stable phase of its life cycle, fusing hydrogen into helium in its core. The star is relatively faint compared to the Sun, with a stellar magnitude of 14.092. This means that it is not visible to the naked eye, and astronomers rely on specialized instruments to study it. The star’s faintness also affects the amount of light reaching K2-120 b, which is crucial in determining the planet’s surface temperature and potential for life.

The relatively low luminosity of the star likely means that K2-120 b experiences extreme temperature variations, especially considering its proximity to the host star. This close orbit, combined with the planet’s larger size and mass, suggests that K2-120 b may have a dense atmosphere or even a thick cloud cover, which could trap heat and contribute to a runaway greenhouse effect, making the planet even hotter.

The Transit Method and its Role in Discovery

The primary method used to detect K2-120 b was the transit method, which involves monitoring a star’s light curve for periodic dips in brightness. When a planet passes in front of its star from our point of view, it blocks a portion of the star’s light, causing a temporary decrease in brightness. By measuring these dips, astronomers can infer the size, mass, and orbital characteristics of the planet.

The Kepler and K2 missions have revolutionized the search for exoplanets by using this method. By observing thousands of stars over extended periods, the K2 mission has been able to identify a diverse array of exoplanets, including Super Earths like K2-120 b. The data from these missions provides crucial information for understanding planetary systems beyond our own, offering insights into the formation and evolution of planets in different environments.

Potential for Habitability

Although K2-120 b’s close orbit and high mass suggest that it is an inhospitable world, its discovery still holds significant scientific value. As with many Super Earths, K2-120 b could potentially have a thick atmosphere composed of gases like hydrogen, helium, or carbon dioxide. However, given its close proximity to its host star, it is unlikely to support life in the way Earth does, as the temperatures would be far too high for liquid water to exist on its surface.

The study of K2-120 b, along with other Super Earths, helps scientists understand the range of possible conditions that exist in the universe. Even though it may not be a candidate for life, it provides important data that can be applied to other exoplanets, some of which may be in the habitable zone of their stars, where conditions could be more favorable for life.

Future Research and Exploration

As technology advances, scientists will continue to study K2-120 b and other exoplanets in greater detail. Future space telescopes, such as the James Webb Space Telescope (JWST), may be able to gather more information about the planet’s atmosphere, composition, and potential for habitability. Additionally, more advanced models of planetary formation and evolution will help astronomers better understand the conditions that lead to the formation of Super Earths and the role these planets play in the broader context of galaxy evolution.

The study of planets like K2-120 b is essential for expanding our understanding of the universe. While K2-120 b may not be a suitable home for life, its discovery adds to the growing body of knowledge about the variety of planetary systems in existence. As scientists continue to explore distant worlds, they come closer to answering some of the biggest questions about the potential for life elsewhere in the cosmos.

Conclusion

K2-120 b, a Super Earth exoplanet discovered in 2017, is a captivating example of the diversity of planets that exist beyond our solar system. Despite its inhospitable conditions, the planet’s discovery provides valuable insights into the characteristics of planets that orbit distant stars. Its large size, short orbital period, and eccentric orbit make it a unique object of study. As our ability to detect and analyze exoplanets improves, discoveries like K2-120 b will continue to shape our understanding of the universe and the countless planets that populate it.

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