synonymGiant planet(Giant planet) generally refers to gas giant planet
Gaseous giantplanet(Gas Giant), also known as Jovian planet, is a planet or giant planet outside Jupiter, which is not composed of rocks or other solidsMegaplanets。Jupiter and Saturn are huge in size and mass, but their density is small, mainly composed of hydrogen, helium, neon, etcElement composition。[1]
Chinese name
gas giant
Foreign name
Gas Giant
Alias
Jupiter like planet
Definition
A large planet that is not mainly composed of solids
staysolar systemThere are 4 gas giant planets inside:Jupiter、Saturn、UranusandNeptune。Many of theExoplanetHas been confirmed to be a gas giant planet[2]。As of May 14, 2022, 5004 gas giant planets have been confirmed.It is better than Class B planets（Gaseous planet）Slightly larger.
Planetary classification
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The gas giant planets can be divided into different types. The "traditional" gas giant planets are Jupiter and Saturn, and the main components are hydrogen and helium.UranusandNeptuneBecause the main ingredients are water, ammoniamethane, while hydrogen and helium are only the main components of the outermost region, so they are sometimes subdivided into“Ice giant”。Almost all exoplanets are gas giant planets with high surface temperature, classified asHot JupiterAnd hot Jupiter is also the most common type of exoplanets.
Relevant definitions
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Jupiter, one of the gas giant planets
The definition of "gas giant planet" is easy to be understood as lacking a solid surface, but it is more accurate to say that the surface is difficult to be clearly defined.In fact, although they have rock or metal cores, such cores are believed to be absorbed by the gas giant planets themselves, Jupiter andSaturnThe main masses are still hydrogen and helium.In the upper part of the planet, the main element is still gas, which is the case on the earth. But in the lower part of the planet, they are compressed into liquid or solid, and the density is higher as the core goes.Similar, althoughUranusandNeptuneMost of them are cold ice. The extreme heat and pressure inside these planets make ice enter a physical state that we are not familiar with.Therefore, it is traditionally believed that people cannot "land" on gas giant planetsSurface area, volumesurface temperature ,, and surface density are only related to the outermost layers visible from space.
Exoplanet
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A newly discovered extrasolar gas giant planet has been carried outDirect imaging。This exoplanet is about 300 light-years away from the Earth. It is extremely difficult to directly image such a target. This may be the smallest exoplanet with the lowest quality for direct imaging so far.
The image of HD95086 b, next to which is the star orbiting
On June 3, 2013, the European Southern Observatory released a clear image of a gas giant planet (No. HD 95086 b) orbiting a young star (HD 95086). The image was taken in the infrared band.In the image, the light of the central star is blocked to show the bright light of the traveling star.Exoplanet HD 95086 bEuropean Southern ObservatoryOfVery large telescopeCapturing direct images.Based on the brightness of this exoplanet, scientists estimate that its mass is only 4-5 times that of Jupiter.
This star and the planets around it are placed in the southern skyShip baseIn the starry sky background.This exoplanet orbits its star about the distance from Neptune tosunlightTwice the distance, or 56 times the distance from the earth to the sun.The blue circle in the image represents the orbital size of Neptune, so as to compare the actual scale of the two.
Detection method
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With the help of indirect methods, astronomers are discovering more and more exoplanets. Such methods include detecting the effects of planets blocking lightStellar brightnessDecline, or slight wobble of stars due to the influence of planetary gravity, etc.
Direct imaging
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Julian·Latin AmericaJulien Rameau is from FranceAstrophysicsandPlanetologyThe scientist of the Institute is also the first author of the paper on this research.He said: "Direct imaging of exoplanets is a challenging task, which requires the help of the most advanced equipment in space or on the ground. So far, only a few exoplanets have achieved direct imaging, and each such imaging marks a milestone in understanding the nature and evolution mechanism of giant planets."
Planetary observation
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In June 2013, scientists found the star HD 95086, which is a relatively young star with an age of only 10 million to 17 million years.There are planets andDust panThis has aroused great interest of researchers.Scientists believe that this planetAccretion diskThe interaction between, or with other planets around the star, may cause the planet to deviate from its original position.Details of this study will be published in the《Journal of Astrophysics》On.[3]
In July 2020, scientists discovered a new type of celestial body, which is "dancing" with a distant star.The object may be the core of a gas giant planet.The research results show that the planet orbits a star 370 light-years away from EarthHelioid starIts radius is about 3 and a half times that of the earth, but its mass is about 39 times that of the earth.Since TOI 849 b is very close to the parent starRevolution periodIn only 18 hours, the surface temperature reached 1527 ℃.[4]
scientific research
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In 2023, the research team of Massachusetts Institute of Technology reported the process of a planet or being "swallowed" by a host star:A giant planet is too close to the host star, and after interacting with the host star for a period of time, a radiation explosion occurs, which may be related to the engulfment of the star on the planet.[5]
