If you wanted to do a forensic analysis of the Solar System, then you might head for the most central asteroid belt between Mars and Jupiter. Here are some ancient debris from the Solar System''s early days. Out there in the cold vacuum of space, far from the Sun, asteroids are mostly untouched by space weathering.
Because of their evidence, space scientists often refer to asteroids and their meteorite fragments that fall to Earth as time capsules.
The asteroid Psyche is particularly interesting, and NASA is conducting a research to discover the unusual chunk of rock.
A team of researchers combined observations of Psyche from an array of telescopes to create a map of the asteroid''s surface before completing the mission.
Asteroids are divided into three categories, each of which is carbonaceous or C-type asteroids. It is estimated that they contain approximately 75 percent of known asteroids, which makes them dense. Their carbon makes them dark and they have low albedoes.
Asteroids of Silicaceous or S type are the second most common type. They make up about 17 percent of known asteroids and are mostly made of iron and magnesium silicates.
Metal or M-type asteroids are the most common types of asteroids, making up about 8 percent of the commonly used asteroids. They appear to contain more metal than the other asteroid types, and scientists believe it is the source of iron meteorites that fall to Earth. M-type meteorites were one of the earliest sources of iron in human history.
Psyche (16 Psyche) is an M-type asteroid. It is also known as a dwarf planet because it is about 220 kilometers (140mi) in diameter. It''s also known as 16 Psyche because it was the 16th minor planet discovered. (Larger asteroids like Psyche are also known as minor planets.)
(NASA/JPL-Caltech/ASU)
Because of the wealth of iron and nickel it contains, Psyche is sometimes referred to as the "Gold-mine asteroid." Although, nobody believes it is rich in gold.
The VLT of the European Southern Observatory captured some images of the asteroid, but none of them revealed much information.
The psyche''s history is a rocky history. For a long time, astronomers believed it was the exposed iron core of a much larger body. In this reasoning, a large collision or a series of collisions stripped away the body''s crust and mantle.
The larger body would''ve been fully differentiated and measured about 500 km (310 miles) in diameter. Only the iron-rich core remained with the crust and the mantle gone.
As time passed, the idea fell out of favor, and astronomers continued observing it. It was not enough to be solid iron, but it is likely to porous.
Other researchers claim that Psyche was disrupted somehow and then re-accreted as a mix of metals and silicates. One study reveals that Psyche isn''t as metal-rich as thought and is more of a rubble pile. In this scenario, collisions with more common C-type asteroids deposited a layer of carbon and other components onto the Psyche''s surface.
Ferro-volcanic theory is the most exorcise behind Psyche''s origins. A2019 study showed that Psyche was once a molten blob. In that scenario, the outer layers cooled and formed stress cracks, and the buoyant molten core erupted as iron volcanoes.
The only way to know for sure what Psyche is is to go and look at it. So that''s what NASA is doing.
The mission, Psyche, will begin in fall 2022, owing to solar-electric propulsion and a gravity-assist maneuver. In 2026, the spacecraft will be equipped with Mars to reach Psyche.
It''ll spend 21 months studying the asteroid and will follow four different orbital paths, each one a day closer than the previous.
A photo of the Psyche probe near the Psyche asteroid. (NASA/JPL-Caltech/ASU)
As the asteroid approaches, it''ll focus on different scientific objectives.
A team of researchers constructed a new map of the Psyche''s surface in order to assist prepare for the mission.
The map is found in a paper published in the Journal of Geophysical Research: Planets. The title is "The Heterogeneous Surface of Asteroid (16) Psyche," and the lead author is Saverio Cambioni, a member of the MIT Department of Earth, Atmospheric and Planetary Sciences (EAPS).
Cambioni said in a press release that "Psyche''s surface is very heterogeneous." "These maps confirm that metal-rich asteroids are interesting enigmatic worlds. It''s another reason to look forward to the Psyche mission going to the asteroid."
TheAtacama Large Millimeter/Submillimeter Array(ALMA) used to better understand the 16 Psyche. ALMA is a radio telescope composed of 66 high-precisionantennae. The separate antennae operate together as an interferometer with a high resolution.
ALMA operates at wavelengths that are sensitive to the temperature and some electric properties of materials on Psyche''s surface.
"The ALMA antenna signals can be combined into a synthetic signal that''s equivalent to a telescope with a diameter of 16 kilometers (10 kilometers," says Caltech''s co-author. "Jet larger the telescope, the higher the resolution."
The new study is based on two kinds of measurements. One isthermal inertia, which is how long a material takes to reach the temperature of its environment. Higher thermal inertia means it takes longer.
Thesecond is thedielectric constant. The dielectric constant explains how well a material conducts heat, electricity, or sound. A material with a low dielectric constant conducts poorly and is a good insulator and vice versa.
Researchers analyzed the ALMA''s thermal inertia and dielectric constant and conducted hundreds of simulations to see which combinations of materials could explain them. "We conducted these simulations area by area so we could detect differences in surface properties," Cambioni said.
Pure iron has an infinite dielectric constant. The researchers may then identify areas richer in iron by measuring the dielectric constant on Psyche. Iron also has a huge thermal inertia because it''s so dense.
So, by combining thermal inertia and dielectric constant measurements, you''ll get an idea of which surface regions on Psyche are rich in iron and other minerals.
In the picture below, Psyche the Bravo-Golf region shows a surprising feature. That region has a systematically lower thermal inertia than the highland areas. The Bravo-Golf region is the region''s only meridian, which is narrow to the right.
Why is a low-elevation area a lower thermal inertia? Other research suggest that the region is also radar-bright. What''s the problem? The researchers presented several theories.
The lowlands might be metal-rich but covered with a fine, porous regolith that decreases their thermal inertia compared to the highlands covered in coarser regolith. Thermal inertial increases with particle size. In this scenario, finer-grained regolith would''ve envelopped in the lowlands.
"It''s very interesting and mysterious that small asteroids have been seen several hours of fine-grained material," said Cambioni. "But Psyche is a large body, so if fine-grained materials accumulate on the bottom of the depression, they''ll shake the surface and drain finer materials. "It''s very large, though."
The second theory is that the surface material covering the lowlands is more porous than the highlands. Thermal inertia decreases as rock porosity increases. Impact fractures may make the lowlands more porous.
The third assumption is that the lowlands have more silicate-rich materials than the highlands, resulting in a lower dielectric constant than some areas of the highlands. The Bravo-Golf depression might''ve been formed by an impact with a silicate-rich impactor, resulting in a residue that is not silicate-rich.
The study has shown that the 16 Psyche''s surface is covered in a wide variety of materials. It also provides additional evidence that the asteroid is metal-rich, although the abundance of metals and silicates is significant in different regions.
It suggests that the asteroid might be a remnant core of a differentiated body that had lost its mantle and crust long ago.
"In conclusion, we demonstrate that Psyche is a metal-rich asteroid with a wider surface, both metal and silicate materials, and that it is likely to evolve due to its impacts," the authors conclude.
Simone Marchi, a staff scientist at the Southwest Research Institute and a co-investigateur on NASA''s Psyche mission, spoke out about the study''s significance in a press release. "These findings indicate that thePsychemission''s surface is heterogeneous, with potentially significant differences in composition. So, thePsycheScience Team is keen to investigate more."
NASA''s Psyche mission will be able to confirm these findings more rigorously.
Psyche''s sending a spacecraft all the way to the ground isn''t about just Psyche itself.
If Psyche is the remnant core of a rocky, differentiated planetesimal, it will reveal more about our planet and how differing bodies form. Will it contain some of Earth''s core''s light elements that we expect aren''t made of iron and nickel? Scientists believe it contains lighter elements such as sulfur, silicon, oxygen, and carbon.
The Psyche mission will also determine whether the asteroid formed under conditions is more oxidizing or less reduction than Earth''s core. That will also inform us more about the solar nebula and the protoplanetary disk.
Because of its high metal-rich size, people often refer to Psyche as the Gold Mine Asteroid. An object such as Psyche would contain an enormous amount of iron, although that value is unlikely to be realized or accessible anytime soon.
If knowledge is as valuable as iron, then 16 Psyche may still be a gold mine.
This article was originally published by Universe Today. Read the content here.
