University of ArizonaDavid Cantillo 氏Their research group is believed to be mostly made of metalAsteroid “Psyche”About (16 Psyche)Metal content may be slightly lower than previously expected and average density may be lower than expectedWe announced the research results showing.
■ The actual Psyche may be an asteroid close to the Rubble Pile
Psike is between Mars and JupiterAsteroid beltOn an asteroid located inAverage diameter is 226kmIt has been with.Japan Aerospace Exploration Agency (JAXA) asteroid explorer“Hayabusa2”Taken a sampleAsteroid “Ryugu”The diameter ofAbout 900mTherefore, even if it is the same asteroid, Psyche isApproximately 250 times that of RyuguThere will be a size of.
As I mentioned at the beginning, PushikeironOrnickelRich in metals such as“M-shaped Little Planet”It is classified into.As its true identity, it once existed in the solar systemThe exposed core of the planetThere is a possibility that it is.
Fluffy and tiny in the early solar systemdustGatheredPlanetesimalFormed and planetesimals gatheredProtoplanetIs believed to have been formed.Inside the melted planetesimals and protoplanets, light rock components are separated upwards and heavy metal components are separated downwards.“Differentiation”A process called is progressing, depending on the rock compositionMantleBut due to the sunken metal componentcoreIs believed to have been formed.
Psike was lost on the outside when another celestial body collided with an early planet with advanced internal differentiation.Isn’t it a celestial body with only the core made of the inner metal component remaining?That’s why.Psyche is drawing attention because it may provide insights into the planet’s core, and the National Aeronautics and Space Administration (NASA) is an asteroid explorer that observes Psyche.「Psyche」(in English“Saiki”) Launch2022I am planning to.
This time, the research group created a sample that imitated the regolith on the surface of Psike in the laboratory, and actually observed the visible light and infrared rays of Psike.SpectrumThe composition that matches (intensity of electromagnetic waves for each wavelength) was investigated.As a result, the research groupComposition of PushikeToMetal 82.5%, Low in ironPyroxene 7%、Carbonaceous chondrite 10.5%、Porosity of Pushike(Volume ratio of gaps contained in soil and rocks)About 35%I presume.
This is compared to previous expectationsLow metal content and high porosityIt is said to mean (there are many internal gaps). Cantillo said Psike contains carbonaceous chondritesCollision with more common asteroidsI have pointed out that the debris generated at that time may have accumulated on the surface.
Also, in the announcement, it is estimated that the porosity is 50% or more, not the appearance of the exposed planet core as it is.Asteroid “Bennu”(NASA asteroid explorer“OSIRIS-REx”Collects samples) and like Ryugu,In reality, it may be close to a rubble pile object made up of accumulated rubble.Is mentioned. If NASA’s psychic mission goes according to plan,2026Should reveal the true picture of Pushike.
Related: $ 10,000,000,000,000,000,000 asteroid “Psyche”
Image Credit: NASA/JPL-Caltech/ASU
Source: University of Arizona
Sentence / Takehiro Matsumura