Astrophile: Heavy metal asteroid is a spacecraft magnet

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Astrophile: Heavy metal asteroid is a spacecraft magnet

Post by bystander » Thu Dec 26, 2013 11:01 pm

Heavy metal asteroid is a spacecraft magnet
New Scientist | Astrophile | Lisa Grossman | 2013 Dec 20

Object: asteroid 16 Psyche
Alter ego: naked metal core

If Jules Verne were alive, he'd raise a toast. In a twist on his notion to journey to the centre of the Earth, a proposed spacecraft may get to visit the core of a proto-planet that was long ago stripped of its rocky outsides and cast adrift in the solar system.

Asteroid 16 Psyche was discovered in 1852, but it was not until the 1980s that it was recognised as an oddball. Radar observations made from Earth revealed that Psyche is about 200 kilometres across and is made of 90 per cent iron and nickel, with 10 per cent silicate rock.

This composition is strikingly similar to that of Earth's metal core. That means Psyche could have started life as a small rocky world with a metal core and a silicate mantle, similar to the large asteroid Vesta. And astronomers think larger planets like Earth and Venus could have formed when such nascent worlds collided and merged.

But other times, incoming asteroids might have stripped a proto-planet of its soft outer layers. Psyche could have fallen victim to a series of hit-and-runs that robbed it of its mantle, leaving just the metallic core behind. If that core had been liquid at some point, it would have given the object a strong magnetic field. In fact, Psyche could still have a remnant field almost as strong as the Earth's.

Unique core sample

"It could be like a little refrigerator magnet in space," says Linda Elkins-Tanton of the Carnegie Institution in Washington DC, who presented an idea for a mission to Psyche at a meeting of the American Geophysical Union in San Francisco last week.

"A mission there is the only way that humankind will ever visit the core of any body," says Elkins-Tanton. "We can learn about the building blocks of the planets in the first million years of the solar system in a way that we can't do any other way." Her team's proposed spacecraft would orbit the asteroid for about six months, making measurements of the metal world's gravity, composition and topography.

Physically, Psyche could look quite different from any other space object we've yet seen. Physicists have run laboratory experiments on how impact craters form on metal surfaces, and they suggest that Psyche's craters could have dramatic rims that froze in splash-like patterns.

"But here's the thing: we don't know what we're going to see," says Elkins-Tanton. "We've seen rock worlds and ice worlds and gas worlds, but we've never visited a metal world. We have no idea what it will look like. We only know we're going to be surprised."

Evidence of a metal-rich surface for the asteroid (16) Psyche from interferometric observations in the thermal infrared - Alexis Matter et al
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Re: Astrophile: Heavy metal asteroid is a spacecraft magnet

Post by BDanielMayfield » Sat Dec 28, 2013 4:20 am

This is an important object. 16 Psyche could be the parent body of some relatively rare meteorites.
Wikipedia wrote:About 5% of meteorites that fall are iron meteorites with intergrowths of iron-nickel alloys, such as kamacite and taenite. Most iron meteorites are thought to come from the cores of asteroids that were once molten. As on Earth, the denser metal separated from silicate material and sank toward the center of the asteroid, forming a core. After the asteroid solidified, it broke up in a collision with another asteroid. Due to the low abundance of iron meteorites in collection areas such as Antarctica, where most of the meteoric material that has fallen can be recovered, it is possible that the percentage of iron-meteorite falls is lower than 5%.

Stony-iron meteorites constitute the remaining 1%. They are a mixture of iron-nickel metal and silicate minerals. One type, called pallasites, is thought to have originated in the boundary zone above the core regions where iron meteorites originated. The other major type of stony-iron meteorites is the mesosiderites.
So chips off this old block could very well already be here on earth, even in meteorite colections. Meteorite hunters often test their finds for magnetism.

Also, it was mentioned in the article bystander provided that:
Psyche could have fallen victim to a series of hit-and-runs that robbed it of its mantle, leaving just the metallic core behind. If that core had been liquid at some point, it would have given the object a strong magnetic field. In fact, Psyche could still have a remnant field almost as strong as the Earth's.
The core of this asteroid must have been liquid early in our solar system’s history. It is thought that the protostellar cloud that the sun and its planetary family formed from was compressed and seeded with elements produced by a nearby Supernova. This supernova would have produced radioactive elements like Uranium and even Aluminium that would have helped heat the interiors of planetestimals to the point of melting.
Wikipedia wrote:Meteorite research has also shown that 26Al was relatively abundant at the time of formation of our planetary system. Most meteorite scientists believe that the energy released by the decay of 26Al was responsible for the melting and differentiation of some asteroids after their formation 4.55 billion years ago.
26Al has a half life of 717,000 years and decays into the stable isotope Magnesium-26. Both Al and Mg are much lighter than Fe and Ni, so once the interiors of planetestimals melted Al and Mg would have floated upward while Fe and Ni and other heavy elements settled into the cores. These heavier elements would have included some gold and uranium, so 16 Psyche should be a good place to go prospecting.

Thar's gold in that thar ‘roid, I’d wager.

Bruce
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Re: Astrophile: Heavy metal asteroid is a spacecraft magnet

Post by neufer » Thu Oct 01, 2015 1:25 pm

https://en.wikipedia.org/wiki/16_Psyche wrote: <<16 Psyche (Ψυχή, "Soul") is one of the ten most-massive asteroids in the asteroid belt. It is over 200 kilometers in diameter and contains a little less than 1% of the mass of the entire asteroid belt and it is thought to be the exposed iron core of a protoplanet. It is the most massive metallic M-type asteroid. Psyche was discovered by Annibale de Gasparis on 17 March 1852 from Naples and named after the Greek mythological figure Psyche.

A proposal for an unmanned Psyche orbiter has been made by a team led by Lindy Elkins-Tanton, the director of the School for Earth and Space Exploration at Arizona State University. This team argues that Psyche would be a valuable object for study because it is the only metallic core-like body discovered so far. The proposed spacecraft would orbit Psyche for six months, studying its topography, surface features, gravity, magnetism, and other characteristics and would be based on current technology, avoiding high cost and the necessity to develop new technologies. The team, who have been working on their plan for about one and a half years, plan to submit it in 2015 as a proposal for NASA's Discovery Program, which invites proposals for low-budget robotic space exploration missions. On September 30, 2015, the Psyche mission was one of five Discovery proposals selected to proceed into Step 2.

The first fifteen asteroids to be discovered were given symbols by astronomers as a type of shorthand notation. In 1851, however, J. F. Encke suggested using a circled number, and 16 Psyche was the first new asteroid to be discovered that was designated with this scheme (in 1852 by J. Ferguson). However, Psyche was given an iconic symbol as well, as were a few other asteroids discovered over the next few years. This symbol, a semicircle topped by a star, represents a butterfly's wing, symbol of the soul (psyche is the Greek word for 'soul'), and a star.

Radar observations indicate that Psyche has a fairly pure iron–nickel composition. Unlike some other M-type asteroids, Psyche shows no sign of the presence of water or water-bearing minerals on its surface, consistent with its interpretation as a metallic body. Psyche seems to have a surface that is 90% metallic (iron), with small amounts of pyroxene.

Psyche thus appears to be an exposed metallic core from a larger differentiated parent body. If Psyche is indeed the core remnant of a larger, now destroyed, parent body, we might expect to find other asteroids on similar orbits. However, Psyche does not belong to any asteroid family. One hypothesis is that the collision that formed Psyche occurred very early in the Solar System's history, and all the other remnants have since been ground into fragments by subsequent collisions or had their orbits perturbed beyond recognition.

Psyche is massive enough that its perturbations on other asteroids can be measured, which enables a mass measurement. IRAS data shows it to have a diameter of 253 km. Observations of an occultation using five chords suggest an outline of 214×181 km. Recent estimates of Psyche's smaller size has resulted in an increase in its estimated density to one that is more appropriate for a metallic asteroid. Psyche appears to have a fairly regular surface and is approximately ellipsoidal in shape. Light-curve analysis has indicated that Psyche's pole points towards either ecliptic coordinates (β, λ) = (−9°, 35°) or (β, λ) = (−2°, 215°) with a 10° uncertainty. This gives an axial tilt of 95°.

Two stellar occultations by Psyche have been observed (from Mexico on 22 March 2002 and another on 16 May 2002). Light-curve variations indicate a non-spherical body, consistent with the light-curve and radar results.

It is possible that at least some examples of enstatite chondrite meteorites originated from this asteroid, based on similar spectral analysis results.>>
Art Neuendorffer

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Re: Astrophile: Heavy metal asteroid is a spacecraft magnet

Post by neufer » Thu Oct 01, 2015 4:48 pm

https://en.wikipedia.org/wiki/The_Magnetic_Monster wrote:
Click to play embedded YouTube video.
<<The Magnetic Monster is a 1953 independent science fiction film, directed by Curt Siodmak, and starring Richard Carlson, King Donovan and Jean Byron

A pair of agents from the Office of Scientific Investigation (OSI) are sent to investigate a local appliance store, where all of the clocks have stopped at the same time, and metal items in the store have been magnetized. The source of this is traced to an office located directly above the store, where scientific equipment is found, along with a dead body. There are also signs of radioactivity, but the cause of the difficulties itself is clearly no longer in the room, or the immediate area.

Investigation and request for citizen input eventually lead to an airline flight carrying a scientist, Dr. Howard Denker, who has developed signs of radiation sickness related to something in a heavy briefcase he carries and clutches irrationally. Before dying, he confesses to have been experimenting with an artificial radioactive isotope, serranium, which he had bombarded with alpha particles for 200 hours (8 days and 8 hours). Unfortunately, his so-far microscopic creation has taken on a life of its own: it must absorb energy from its surroundings every 11 hours, and in the process doubles in size and mass each time, releasing deadly radiation and incredibly intense magnetic energy.

The OSI officials realize that, with its rate of growth, it will only be a matter of days before it becomes large enough to affect the Earth's rotation on its axis and spin it out of orbit. They also discover that the isotope is impervious to any known means of destroying it or even rendering it inert. The only answer appears to be to use a Canadian experimental power generator being constructed in a cavern under the ocean, with the hopes of bombarding the element with so much energy in one surge that it neutralizes itself with its own "gluttony".
  • Gen. Behan: The Canadian government operates a top-secret plant in Nova Scotia. They own the most powerful Deltatron in existence. When they realize the common danger, they'll let us use it.

    Mayor: Nova Scotia is 4000 miles away. The period between cycles is 11 hours. How are we gonna transport it there in that time?

    Gen. Behan: Our jets travel at 600 miles an hour. And what's more, the new alloys used in our jets are non-magnetic. They will not be affected by the cargo. You, Dr. Stewart, and Forbes can follow in another plane, just in case.>>
Art Neuendorffer

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Re: Astrophile: Heavy metal asteroid is a spacecraft magnet

Post by Sawngrighter » Thu Oct 01, 2015 10:04 pm

16 Psyche .. is it the core of the planet that was became the asteroid belt? Some of the asteroids have magnetic fields .. http://www.space.com/28319-asteroid-mag ... -core.html. Phobos is said to perhaps have come from the asteroid belt and it shows layers as if once part of a planet.

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