The Psyche asteroid is packed full of precious metals and could be worth more than $10,000 quadrillion (£8,072 quadrillion), new measurements of its surface temperature have confirmed.
Psyche is a 124 mile-wide space rock that orbits the sun in the asteroid belt, a donut-shaped region of space between Mars and Jupiter containing over a million rocks.
NASA is sending a mission to study the metal rich asteroid in 2026 in an effort to determine its origins, with some speculation it was the core of an early planet.
To help in this mission, a new temperature map has been created of Psyche by a team from Caltech in Pasadena, California to provide insight into its surface properties.
Normally, infrared images of a space rock provide a single pixel of data, but using the Atacama Large Millimeter/submillimeter Array (ALMA) in Chile, researchers were able to get 50 pixel resolution and learn more about the surface of the space rock.
They were able to determine it has a metallic surface made up of at least 30 per cent metal and that the rocks on the surface are peppered with metal grains.
It is hoped this will help NASA in its mission, as it will have a more detailed starting point in its observations.
The first high-resolution measurements of the surface temperature of asteroid Psyche confirms it is packed full of $10,000 quadrillion worth of precious metal
To help in this mission a new temperature map has been created of Psyche by a team from Caltech in Pasadena, California to provide insight into its surface properties
Psyche 16 was originally discovered in 1852 and is believed to be the remnants of a protoplanet destroyed by ‘hit-and-run collisions’ when the solar system was forming.
Unlike other rocky or icy bodies, Psyche 16 is suspected to be made of mostly iron and nickel, and could be worth quadrillions of dollars in potential mining value.
Ahead of the NASA mission, the team from California carried out a close examination of the millimeter-wavelength emissions from the asteroid.
This allowed them to produce the first temperature map of the space rock, providing new insight into its surface properties.
‘The findings are a step toward resolving the mystery of the origin of this unusual object, which has been thought by some to be a chunk of the core of an ill-fated protoplanet,’ according to the study authors.
Psyche is the largest of the M-Type asteroids, an enigmatic class of asteroids that are thought to be metal rich and therefore potentially may be fragments of the cores of proto-planets that broke up as the solar system formed.
‘The early solar system was a violent place, as planetary bodies coalesced and then collided with one another while settling into orbits around the sun,’ says Caltech’s Katherine de Kleer, assistant professor of planetary science and astronomy.
‘We think that fragments of the cores, mantles, and crusts of these objects remain today in the form of asteroids. If that’s true, it gives us our only real opportunity to directly study the cores of planet-like objects.’
Studying such relatively tiny objects that are so far from Earth, with Psyche as far as 200 million miles away, poses a significant challenge to planetary scientists.
Typically, thermal observations from Earth – which measure the light emitted by an object itself rather than light from the sun reflected off of that object – are in infrared wavelengths and can produce only 1-pixel images of asteroids.
However, that single pixel contains a lot of information on an asteroid, such as the thermal inertia, or how fast it heats up in sunlight and cools in darkness.
An artists’ depiction of what the 16 Psyche spacecraft will look like. It is slated to launch in August 2022
‘Low thermal inertia is typically associated with layers of dust, while high thermal inertia may indicate rocks on the surface,” says Caltech’s Saverio Cambioni.
‘However, discerning one type of landscape from the other is difficult.’
Viewing the each surface location at many times of day helps to providee greeater levels of detail and an interpretation with less ambiguity.
This in terms provides a more reliable prediction of the landscape before the arrival of the NASA probe – allowing the mission to gather more reliable data.
De Kleer and Cambioni, together with co-author Michael Shepard of Bloomsburg University in Pennsylvania, took advantage of the Atacama Large Millimeter/submillimeter Array (ALMA) in Chile to obtain such data.
The array of 66 radio telescopes enabled the team to map the thermal emissions from Psyche’s entire surface at a resolution of 18 miles (30 kilometres).
In the dataset each pixel is 18 miles x 18 miles, and when combined generate an image of the asteroid composed of about 50 pixels.
This provides significantly better resolution and data than the typical single pixel images obtained of the surface of these asteroid belt space rocks.
It was possible as ALMA observed the space rock at millimeter wavelengths, longer than the infrared wavelengths used in previous observations of the rock.
The use of longer wavelengths allowed the researchers to combine the data collected from the 66 telescopes to create a much larger effective telescope; the larger a telescope, the higher the resolution of the images it produces.
The study confirmed that Psyche’s thermal inertia is high compared to that of a typical asteroid, indicating it has an unusually dense or conductive surface.
When de Kleer, Cambioni, and Shepard analysed the data, they also found that Psyche’s thermal emission, that is the amount of heat it radiates, is 60 per cent of what would be expected from a typical surface with thermal inertia.
Because surface emission is affected by the presence of metal on the surface, their finding indicates that Psyche’s surface is no less than 30 per cent metal.
Normally infrared images of a space rock provide a single pixel of data, but using the Atacama Large Millimeter/submillimeter Array (ALMA) in Chile, researchers were able to get 50 pixel resolution and learn more about the surface of the space rock
An analysis of the polarisation of the emission helped the researchers to roughly determine what form that metal takes.
A smooth solid surface emits well-organised polarised light, but the light emitted by Psyche was scattered – suggesting surface rocks are peppered with metallic grains.
‘We’ve known for many years that objects in this class are not, in fact, solid metal, but what they are and how they formed is still an enigma,’ de Kleer says.
The findings reinforce alternative proposals for Psyche’s surface composition, including that Psyche could be a primitive asteroid that formed closer to the sun than it is today instead of a core of a fragmented protoplanet.
It is hoped this will help NASA in its mission due to launch next year and arrive at the rock in 2026, as it will have a more detailed starting point in its observations
The techniques described in this study provide a new perspective on asteroid surface compositions.
The team is now expanding its scope to apply these techniques to other large objects in the asteroid belt.
The study was enabled by a related project by the team led by Michael Shepard at Bloomsburg University that utilised de Kleer’s data in combination with data from other telescopes, including Arecibo Observatory in Puerto Rico, to pin down the size, shape, and orientation of Psyche.
That in turn allowed the researchers to determine which pixels that had been captured actually represented the asteroid’s surface.
Shepard’s team was scheduled to observe Psyche again at the end of 2020, but damage from cable failures shut the telescope down before the observations could be made.
Psyche was discovered by Italian astronomer Annibale de Gasparis on March 17, 1852. He named the asteroid for Psyche, the Greek goddess of the soul who was born mortal and married Eros (Roman Cupid), the god of Love.
This intriguing asteroid is now the primary target of NASA’s Psyche mission, launching next year and arriving at the rock in early 2026.
Over 21 months in orbit, the spacecraft will map and study 16 Psyche’s properties using a multispectral imager, a gamma-ray and neutron spectrometer, a magnetometer, and a radio instrument (for gravity measurement).
The mission’s goal is, among other things, to determine whether Psyche is indeed the core of a planet-sized object or a large metal asteroid.
The findings have been published in the Planetary Science Journal.