Astronomers have unveiled the most detailed map of an asteroid’s metallic soul to date

If you want to conduct a forensic study of the solar system, you can head to the main asteroid between the belt Mars And the Jupiter. This is where you can find ancient rocks from the early days of the solar system. There in the cold void of space, far from the sun, asteroids are largely unaffected by the weather in space.

Astronomers sometimes refer to asteroids — and their meteorite fragments falling to Earth — as time capsules because of the evidence they hold.

Asteroid Psyche is particularly interesting, and NASA sends a mission to investigate the unusual piece of rock.

Prior to this mission, a team of researchers combined Psyche’s observations from an array of telescopes and designed a map of the asteroid’s surface.

Astronomers divide asteroids into three categories. Carbonaceous or C-type asteroids are the most common type. They make up about 75 percent of known asteroids and contain large amounts of carbon. Carbon makes them dark, and they have low albedo.

Silica or S-type asteroids are the second most common type. They make up about 17 percent of known asteroids and are made mostly of iron and magnesium silicate.

Metallic or M-type asteroids are the rarest of all asteroids and make up about 8 percent of all known asteroids. It appears to contain more minerals than other types of asteroids, and scientists believe it is the source of iron meteorites fall to the ground. M-type meteorites were one of the oldest sources of iron in human history.

Psyche (16 Psyche) is an M-type asteroid. It is also called a dwarf planet because it has a diameter of about 220 kilometers (140 miles). It is referred to as 16 Psyche because it was the 16th minor planet discovered. (Larger asteroids such as Psyche are also known as minor planets.)

(NASA/JPL-Caltech/Arizona State University)

Psyche is sometimes called a “gold mine asteroid” because of the wealth of iron and nickel it contains. Although to be clear, no one thinks that it is rich in gold.

Psyche’s visuals don’t tell us much. The European Southern Observatory’s VLT took some pictures of the asteroid, but it didn’t reveal any details.

Psyche’s history is a history of uncertainty. For a long time, astronomers thought it was the exposed iron core of a much larger object. In this hypothesis, a strong collision or series of collisions stripped the body’s crust and mantle.

The larger object was completely discernible and measured about 500 kilometers (310 mi) in diameter. With the crust and mantle gone, only the iron-rich core remained.

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This idea did not get much attention over time and astronomers continued to notice it. Evidence showed that it was not dense enough to be solid iron and likely porous.

Other researchers have suggested that Psyche was somehow disrupted and then reconstituted as a mixture of minerals and silicates. One study indicated That Psyche is not as rich in minerals as thought and more than a pile of rubble. In this scenario, collisions with the more common Type C asteroids deposited a layer of carbon and other materials on Psyche’s surface.

The most outlandish idea behind Psyche’s origins is the iron volcanic notion. a The 2019 study provided evidence That Saeki was once a melting point. In this scenario, the outer layers cooled and formed stress cracks, and the floating molten core erupted as iron volcanoes.

The only way to know for sure what Psyche is is to go and look at it. This is what NASA does.

The mission is called Psyche and is scheduled to launch sometime in the fall of 2022. The spacecraft will rely on solar and electric propulsion and a gravitational maneuver with Mars to reach Psyche in 2026.

It will take 21 months to study the asteroid and will follow four separate orbital paths, each successive path closer than the previous one.

Illustration of the Psyche probe near the Psyche asteroid. (NASA/JPL-Caltech/Arizona State University)

As it approaches the asteroid, it will focus on various scientific goals.

A team of researchers has built a new map of Psyche’s surface to help prepare for the mission.

The map is in a research paper published in Journal of Geophysical Research: Planets. the address is “The heterogeneous surface of the asteroid (16) psychic,And lead author is Saverio Cambioni of the Department of Earth, Atmospheric and Planetary Sciences (EAPS) at MIT.

“Psyche’s surface is very heterogeneous,” Cambioni He said In a press release. “It’s a sophisticated surface, and these maps confirm that metal-rich asteroids are intriguing, mysterious worlds. It’s another reason to look forward to Psyche’s asteroid-going mission.”

In this study, the authors used Large Atacama Group Millimeter / Meter (ALMA) for a better look at 16 psychics. ALMA is a radio telescope consisting of 66 high-resolution antennas. The separate antennas together act as a high-resolution interferometer.

ALMA operates with wavelengths sensitive to temperature and some electrical properties of materials on Psyche’s surface.

“The signals of ALMA antennas can be combined into an artificial signal equivalent to a telescope with a diameter of 16 kilometers (10 miles),” He said Co-author Catherine de Clare, assistant professor of planetary sciences and astronomy at Caltech. “The larger the telescope, the higher the resolution.”

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The new map is based on two types of measurements. One is Thermal inertia, which is the time it takes for a substance to reach its environment temperature. The higher thermal inertia means that it takes longer.

The second is dielectric constant. The dielectric constant describes how well materials conduct heat, electricity, or sound. A material with a low dielectric constant performs poorly and is a good insulator and vice versa.

The researchers took ALMA’s observations of the thermal inertia and dielectric constant and ran hundreds of simulations to see which combinations of materials could explain them. “We ran these simulations region by region so that we could identify differences in surface properties,” Cambioni Says.

Pure iron has an infinite dielectric constant. By measuring the dielectric constant on Psyche, researchers can map the surface and identify areas richest in iron. Iron also has a high thermal inertness because it is so dense.

So, combining the measurements of the thermal inertia and the dielectric constant gives a good idea of ​​the surface regions present in Psyche that are rich in iron and other metals.

Researchers call a peculiar feature on Bravo Golf Psyche. This region has systematically lower thermal inertia than the highland regions. Bravo Golf District is depression Just to the right of the asteroid’s main meridian in the image below.

Why does a low altitude region have a lower thermal inertia? Other studies show that the area is also bright with radar. why is that? The researchers came up with three possibilities.

Lowlands can be rich in minerals but covered with fine, porous craters which reduce their thermal inertness compared to highlands covered with coarse regolith. Thermal inertia increases with particle size. In this scenario, fine regolith gathers in the lowlands.

“Puddles of fine-grained material have been seen on small asteroids, their gravity is low enough that shocks that shake the surface and cause the finer material to collect,” Campione He said. “But Psyche is a big body, so if fine-grained material accumulates at the bottom of the depression, that’s rather interesting and mysterious.”

The second hypothesis is that the surface material covering the lowlands is more porous than the highlands. Thermal inertia decreases with increasing porosity of rocks. Impact fractures can make lowlands more porous, too.

The third hypothesis is that the lowlands contain more silicate-rich materials than the highlands, giving them a lower dielectric constant than some highland areas. The idea is that the Bravo-Golf Depression could have been formed by the impact of a silicate-rich collider leaving a silicate-rich remnant behind.

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In general, the study showed that the surface of 16 Psyche is covered with a large variety of materials. It also adds to other evidence showing that the asteroid is rich in minerals, although the abundance of minerals and silicates varies greatly in different regions.

It also indicates that the asteroid may be the nucleus of the remains of a distinct body that lost its cover and crust long ago.

“In conclusion, we provide evidence that Psyche is a mineral-rich asteroid with a heterogeneous surface, exhibiting both minerals and silicates, and appears to have evolved by impact,” the authors said. deduce.

Simone Marchi is a scientist at the Southwest Research Institute and an associate investigator for NASA’s Psyche mission. Marchi was not involved in this study but hung On its importance in a press release. “These data show that Psyche’s surface is heterogeneous, with marked differences in composition. A primary goal of Psyche’s mission is to study the composition of the asteroid’s surface using gamma rays, a neutron spectrometer, and a color imager. The potential presence of compositional variations is something the psychology team is eager to study. more significantly.”

It will be up to NASA’s Psyche mission to confirm these findings more rigorously.

But sending a spacecraft all the way to Psyche to understand it in more detail is more than just Psyche herself.

If Psyche is the remaining core of a distinct rocky planet, it will reveal something about our planet and how distinct bodies form. Will it contain some of the same light elements we expect to find in Earth’s core? Earth’s core is not dense enough to be pure iron and nickel. Scientists believe that it contains lighter elements such as sulfur, silicon, oxygen, carbon and hydrogen.

The Psyche mission will also determine whether the asteroid formed under more or more contracting oxidizing conditions than the Earth’s core. This will tell us more about the solar nebula and the protoplanetary disk.

People sometimes refer to Psyche as a goldmine asteroid because it is rich in minerals. Any object of its size would contain an enormous amount of iron, although this value is not likely to be achieved or reached anytime soon.

But if knowledge is as valuable as iron, 16 Psyches may still be a goldmine.

This article was originally published by universe today. Read the original article.

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