Science · 16 Psyche

What the research says about 16 Psyche

These are six research papers, all free to read on arXiv, about 16 Psyche. We summarize each one in plain English from its abstract.

Papers 6
Topics 2
Reviewed Oct 24, 2026
Source arXiv.org

Illustrative · not to scale

Our own artist's impression. No figures are taken from the papers.

Known so far

Every number links to the paper it comes from.

Bulk density: 3.88g/cm³1From its mass and volume (± 0.25). Too low for a solid iron core.
Effective diameter: 222km2Size of a sphere with the same volume; the shape is about 278 × 238 × 171 km.

Size, shape & spin

3 papers

How big 16 Psyche is, what shape it has and how it spins.

[1]2021astro-ph.EPPreprint

Mass and Density of Asteroid (16) Psyche

Lauri Siltala & Mikael Granvik

What they foundPsyche's mass came out at about 1.117 × 10⁻¹¹ solar masses, giving a bulk density of about 3.88 g/cm³.

Why it mattersThat density is too low for a solid exposed iron core, but fits the idea that metal-rich lava (ferrovolcanism) once erupted on Psyche.

What they studied

The team weighed Psyche from the gravitational tugs it gave 10 other asteroids during close passes, checking the method on Ceres and Vesta.

Source for: Bulk density

arXiv:2103.01707Abstract (opens arXiv)PDF (opens arXiv)

[2]2021astro-ph.EPPeer-reviewed

Asteroid 16 Psyche: Shape, Features, and Global Map

Michael K. Shepard, Katherine de Kleer, Saverio Cambioni & 9 others

What they foundPsyche measures about 278 × 238 × 171 km (about 222 km across as an equivalent sphere), and its radar brightness suggests a lot of iron-nickel in the top metre.

Why it mattersThis is the reference shape and map that mission planners and scientists use for Psyche.

What they studied

The shape was built from Arecibo radar, ALMA, Keck and VLT adaptive-optics images and a stellar occultation.

Source for: Effective diameter

arXiv:2110.03635Abstract (opens arXiv)PDF (opens arXiv)

[3]2013astro-ph.EPPreprint

Evidence of a metal-rich surface for the asteroid (16) Psyche from interferometric observations in the thermal infrared

Alexis Matter, Marco Delbo, Benoit Carry & 1 other

What they foundPsyche is about 238 to 247 km across, with a smooth surface and one of the highest heat-holding values (thermal inertia) measured for an asteroid that size.

Why it mattersHigh thermal inertia is extra evidence for a metal-rich surface.

What they studied

Astronomers combined light from two VLT telescopes (interferometry) at thermal-infrared wavelengths.

arXiv:1306.2455Abstract (opens arXiv)PDF (opens arXiv)

Surface & composition

3 papers

What 16 Psyche is made of and how its surface behaves.

[4]2024astro-ph.EPPeer-reviewed

The Heterogeneous Surface of Asteroid (16) Psyche

Saverio Cambioni, Katherine de Kleer & Michael Shepard

What they foundPsyche's surface is patchy: its heat-holding ability and its radio reflectivity both vary from place to place, and the two don't line up neatly.

Why it mattersA mixed surface means Psyche isn't a uniform ball of metal, which NASA's Psyche spacecraft will be able to test up close.

What they studied

Researchers re-fitted ALMA radio-telescope maps of Psyche with a model that lets surface properties vary across the asteroid.

arXiv:2402.03422Abstract (opens arXiv)PDF (opens arXiv)

[5]2016astro-ph.EPPreprint

Detection of Water and/or Hydroxyl on Asteroid (16) Psyche

Driss Takir, Vishnu Reddy, Juan Sanchez & 2 others

What they foundPsyche shows a 3-micron absorption feature, the fingerprint of water or hydroxyl bound in minerals.

Why it mattersEither Psyche isn't a pure metal core, or carbon-rich meteorites have delivered hydrated material to it over 4.5 billion years.

What they studied

Astronomers took infrared spectra with NASA's Infrared Telescope Facility in Hawaii.

arXiv:1610.00802Abstract (opens arXiv)PDF (opens arXiv)

[6]2024astro-ph.EPPreprint

Estimate of water and hydroxyl abundance on asteroid (16) Psyche from JWST data

Stephanie G. Jarmak, Tracy M. Becker, Charles E. Woodward & 10 others

What they foundJWST detected the full 3-micron hydration band twice, mostly from hydroxyl (OH), with no sign of the 6-micron band that would mark liquid-like water.

Why it mattersIt confirms hydration on the largest metal-type asteroid with a space telescope and narrows down what kind of water-bearing material is there.

What they studied

The team used JWST spectra covering 1.1 to 6.63 microns.

arXiv:2407.12162Abstract (opens arXiv)PDF (opens arXiv)

New research

New papers on 16 Psyche, checked weekly, summarized after a person reads it.

RSS feed

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How we choose papers

We search arXiv for 16 Psyche papers and keep the ones that add something new, are clearly written up and are relevant to a general reader. A person reads every abstract.

Our own words, our own drawings

Summaries are written by us from each paper’s abstract, not copied. Diagrams are our own simplified drawings, not figures from the papers.

Preprint vs. peer-reviewed

“Peer-reviewed” means arXiv lists a journal reference for the paper. Everything else is marked “Preprint”: shared openly, possibly before or without journal review.

Paper metadata courtesy of arXiv. Summaries written by us; read the original papers via the links. Paper metadata from arXiv.org, which does not endorse this site.