[ad_1]
About two or three times the distance of the Earth from the Sun, in the asteroid belt that lies between Mars and Jupiter, 16 Psyche makes its home. This gigantic metallic asteroid is one of the most massive objects in the asteroid belt, classified as a minor planet.
Astronomers think 16 Psyche is the exposed core of an entire planet that hasn’t made it all the way, and we can’t wait to hear more. NASA will send out a probe to verify this in the next few years, and in the meantime, scientists are working to collect what they can from Earth.
Now, for the first time, 16 Psyche has been studied in ultraviolet wavelengths using the Hubble Space Telescope, revealing that, just as we thought, the dense piece of space rock is remarkably metallic.
“We’ve seen meteorites that are mostly metallic, but Psyche may be unique in that it could be an asteroid made entirely of iron and nickel,” said planetary scientist Tracy Becker of the Southwest Research Institute.
“The Earth has a metallic core, a mantle and a crust. It is possible that while a Psyche protoplanet was forming, it was hit by another object in our Solar System and lost its mantle and crust.”
16 Psyche is a rather fascinating piece of rock. It has a diameter of about 226 kilometers (140 miles) and is only slightly less dense than Earth. Its composition appears to consist of somewhere between 30 and 60 percent metal and the rest of low iron silicate.
If 16 Psyche is a protoplanetary nucleus, it is possible that such impacts have deprived it of its storage material. Planets are thought to form when their stars are very young – perhaps even in tandem – and are surrounded by a thick cloud of dust and gas. The material in this cloud begins to adhere, first electrostatically, then gravitationally as the object becomes more massive.
As these bodies grow, they become warm and somewhat melted, allowing the material to move. Core differentiation is the process by which denser material sinks inward towards the center of the object and less dense material rises outward. For 16 Psyche to be a differentiated core, the protoplanet once had to be much larger than it is now.
Exactly when and how her outer coat was ripped off is a bit of a headache. But Becker’s team research may be the breadcrumb that put us on the trail to figure it out.
“We were able to identify for the first time on any asteroid what we think are ultraviolet iron oxide absorption bands,” he said. “This is an indication that oxidation is taking place on the asteroid, which could be the result of the solar wind hitting the surface.”
In other words, 16 Psyche is getting rusty. And we may be able to figure out how old its surface is based on the amount of oxidation that has occurred, which in turn could give us a timeline of when the asteroid was stripped of its outer material.
The asteroid’s high reflectivity at ultraviolet wavelengths suggests that a long time has passed; usually, ultraviolet brightness is related to space weather. But we won’t know for sure until NASA’s Psyche probe reaches the asteroid around 2026.
Scientists also wish to take a closer look at the composition of 16 Psyche. There is a lot of wiggle room between 30 and 60% metal which made it difficult to track down smaller pieces of rock that could be the result of the impact fragmentation of 16 Psyche’s mantle.
Relatively metallic mesosiderite meteorites were once thought to be remnants of 16 Psyche, but more recent research has found the connection weak.
The work of Becker and his team revealed a spectrum consistent with pure iron, but it could be misleading: as little as 10% of surface iron could dominate the ultraviolet spectrum. There are also very few similar observations of planetary surfaces in the ultraviolet with which to compare the new visions of 16 Psyche.
So obviously we just have to go check it out with a real orbiting probe, which in turn will indicate how well we have tried to understand this strange object from hundreds of millions of kilometers away. Whatever we learn, it will be like looking at a time capsule of the Solar System.
“What makes Psyche and the other asteroids so interesting is that they are considered the building blocks of the Solar System,” Becker said.
“Understanding what a planet really makes up and potentially seeing the inside of a planet is fascinating. Once we get to Psyche, we will really understand if it is, even if it doesn’t turn out as we expect. Whenever there is a surprise, it’s always exciting. “
The research was published in The Planetary Science Journal.
.
[ad_2]
Source link
