Astronomers have revealed the most detailed map of an asteroid’s metallic core to date

If you want to conduct a forensic study of the solar system, you can go to the main site asteroid between the belt Marten It’s at Jupiter. This is where you can find ancient rocks dating back to the early days of the solar system. Out there in the cold vacuum of space, far from the sun, asteroids are 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 have.

Of particular interest is the asteroid Psyche, and NASA is sending a mission to investigate the unusual piece of rock.

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

Astronomers divide asteroids into three categories. Carbonaceous or C-type asteroids are the most common. They make up about 75% of known asteroids and contain large amounts of carbon. The carbon makes them dark and their albedo is low.

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

Metallic or M-type asteroids are the rarest of all asteroids and make up about 8% 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 on 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 called 16 Psyche because it was the 16th minor planet discovered. (Major asteroids such as Psyche are also called minor planets.)

(NASA/JPL-Caltech/Arizona State University)

Psyche is sometimes called “the gold mine asteroid” because of the richness in iron and nickel it contains. Of course, no one thinks they are rich in gold.

Psyche’s visuals don’t tell us much. The European Southern Observatory’s VLT took a few pictures of the asteroid, but did not reveal any details.

The story of Psyche is a story 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 crust and mantle from the body.

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

This idea has not received much attention over time and astronomers have continued to notice it. The evidence showed that it was not dense enough to be solid and probably porous iron.

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

The strangest idea behind Psyche’s origins is the volcanic notion of iron. a A 2019 study provided evidence This Saeki was once a melting point. In this scenario, the outer layers cooled and formed tension cracks, and the floating molten core erupted like iron volcanoes.

The only way to know for sure what Psyche is is to look at her. That’s what NASA does.

The mission is called Psyche and is set to launch in fall 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 last.

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

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

A team of researchers has constructed 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 adress is “The heterogeneous surface of the psychic asteroid (16),And the lead author is Saverio Cambioni of MIT’s Department of Earth, Atmospheric, and Planetary Sciences (EAPS).

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

In this study, the authors used Large Group Atacama Millimeter / Meter (ALMA) to better see 16 mediums. ALMA is a radio telescope made up of 66 high-resolution antennas. The separate antennas together act as a high resolution interferometer.

ALMA works with wavelengths sensitive to temperature and certain electrical properties of materials on the surface of Psyche.

“The signals from ALMA’s 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.”

The new map is based on two types of measurements. A T thermal inertia, that is, the time it takes for a substance to reach room temperature. Higher thermal inertia means it takes longer.

the second is dielectric constant. The dielectric constant describes the ability of materials to conduct heat, electricity or sound. A low dielectric constant material has poor performance and is a good insulator and vice versa.

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

Pure iron has an infinite dielectric constant. By measuring the dielectric constant on Psyche, researchers can map the surface and identify the areas most rich in iron. Iron also has high thermal inertia because it is very dense.

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

Researchers call a special feature of Bravo Golf Psyche. This region has a systematically lower thermal inertia than mountainous regions. Bravo Golf District East the Depression Just to the right of the asteroid’s prime meridian in the image below.

Why does a low altitude region have less thermal inertia? Other studies show that the area is also bright with speed cameras. why is that? The researchers presented three possibilities.

Lowlands can be rich in minerals but covered in thin, porous craters that reduce their thermal inertia compared to uplands covered in coarse regolith. Thermal inertia increases with particle size. In this scenario, fine regolith accumulates in the lowlands.

“Soundings of fine-grained material have been observed on small asteroids, their gravity is low enough that shocks shake the surface and cause finer material to accumulate,” Campione said. He said. “But Psyche is a large body, so if fine-grained material accumulates at the bottom of the depression, it’s quite 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 rock porosity. Impact fractures can also make lowlands more porous.

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

Overall, the study showed that the surface of 16 Psyche is covered with a wide 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 from region to region.

It also indicates that the asteroid could be the core of the remains of a separate body that lost its cover and crust a long time ago.

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

Simone Marchi is a scientist at the Southwest Research Institute and a research associate on NASA’s Psyche mission. Marchi was not involved in this study, but suspended About its importance in a press release. “These data show that the surface of Psyche is heterogeneous, with marked differences in composition. One of the main objectives of the Psyche 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 investigate.

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

But sending a spaceship to Psyche to understand her in more detail is more than Psyche herself.

If Psyche is the residual core of a separate rocky planet, it will reveal something about our planet and the formation of separate bodies. Will it contain some of the same light elements that we expect to find in the Earth’s core? The Earth’s core is not dense enough to be made of pure iron and nickel. Scientists believe 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 contracted oxidative conditions than Earth’s core. This will tell us more about the solar nebula and the protoplanetary disk.

People sometimes refer to Psyche as a gold mine asteroid because it is rich in minerals. Any object of its size would contain a huge amount of iron, although this value is unlikely to be reached or reached anytime soon.

But if knowledge is as precious as iron, 16 Psyches could still be a goldmine.

This article was originally published by universe today. read it original article.

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