Study Findings: Volatile Depletion in Rocky Planets as a Chemical Fingerprint of Hybrid Accretion

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Image (Credit): The Curiosity Mars rover on the Martian surface. (NASA)

Nature Astronomy abstract of study findings:

Volatile depletion in rocky planets relative to their host stars is commonplace in both the Solar System and exoplanetary systems, yet the connections between planet formation and composition remain elusive. Here we model devolatilization during pebble accretion in combination with collisional growth from volatile-depleted planetesimals to explore the formation pathways of Earth and Mars. Using Bayesian inference, we found that bulk silicate Earth is best reproduced by ≳75% contribution from two protoplanets formed via pebble accretion, supplemented by up to ~25% material from planetesimals that are compositionally akin to the asteroid Vesta. Using instead a planetesimal volatile-depletion curve that is not observed among known meteorite parent bodies would allow the planetesimal contribution to reach %. In comparison, bulk silicate Mars reflects 27 ± 5% pebble-accreted material and 73 ± 5% Vesta-like planetesimals. We identified volatile depletion as a chemical fingerprint of hybrid accretion, in which both pebble accretion and collisional assembly contribute to terrestrial planet growth. By quantitatively linking formation pathways to volatile budgets, our findings demonstrate how planetary accretion histories can be inferred from elemental signatures, with broad implications for interpreting the chemical diversity of rocky exoplanets.

Citation:  Wang, H.S., Johansen, A., Xu, Z. et al. Volatile depletion in rocky planets as a chemical fingerprint of hybrid accretion. Nat Astron (2026).

DOI: https://doi.org/10.1038/s41550-026-02984-6

Study-related stories:

University of Copenhagen Global Institute – “New Study Rekindles Contested Question: Earth and Mars Had Different Origins”

Quantum Zeitgeist– “Volatile Loss Reveals How Rocky Planets Grow”

A Moment of Zen: Martian Dawn

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Image (Credit): Zoomed-in crop of a broader panorama captured by NASA’s Curiosity Mars rover on August 11, 2026. (NASA/JPL-Caltech/MSSS)

With all the craziness in the world, it is worth taking a moment away from all of it to look at something different. NASA’s recently released image of a new morning on Mars, taken by the Curiosity rover at 8:30am local Mars time, is just what we need.

You can read more about this image here, once you have a moment to take it in and enjoy it.

Image (Credit): Full panorama shot captured by NASA’s Curiosity Mars rover on August 11, 2026. (NASA/JPL-Caltech/MSSS)

Space Quote: Dumbing Down NASA Contracts

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Credit: Image by OpenClipart-Vectors from Pixabay

“In accordance with Executive Order 14434, Inaugurating the Era of Super Intelligence, this solicitation uses the terminology “Super Intelligence (SI)” exclusively. This includes SI-enabled capabilities such as machine learning, large language models, and foundation models. Please note that certain existing governmental reference materials and documents predating this solicitation may still contain legacy terminology, as they were previously issues before the establishment of Executive Order 14434.”

-Statement in the cover letter to with the subject line “Request for Proposal (RFP), Solicitation No. 80JSC027R0004, for Commercial Low Earth Orbit (LEO) Destination Contract (CLDC) Asquisition.” Basically, NASA is looking for someone to build a space station but it is not allowed to acknowledge the term AI because the White House has a new name for it. It is bad enough NASA cannot say “space station,” but now it is unable to use common industry language when asking for help building one. There is little sign of SI, or any intelligence for that matter, at work in the government these days.

Pic of the Week: The Flower Bud Nebula

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Image (Credit): JWST’s view of NGC 7129. (NASA, ESA, CSA, STScI; Image Processing: Alyssa Pagan (STScI))

This week’s image is from NASA’s James Webb Space Telescope (JWST). It shows the overwhelmingly bright and active NGC 7129, also known as the Flower Bud Nebula, located about 3,300 light-years away.

NASA provided a helpful story explaining what you are seeing in the image above:

The stars from this cluster are in different stages of their development, as the more massive stars form and evolve the fastest. The most massive (and the most mature) is the region’s luminous central star, LkH(alpha) 234 (pronounced Lick-H-alpha). This star, which sports the image’s most prominent diffraction pattern, is a pre-main-sequence star weighing around 5 to 8 times the mass of our Sun. Pre-main-sequence stars like these have mostly finished gathering mass and are contracting under the force of gravity, causing their temperatures to rise. In time, this star will fuse its own hydrogen like our Sun.

The cavity to its left, which appears in gold and spans about 3.5 light-years, is the largest demonstration of the central star’s impact. Outflows from an earlier stage of the star’s life cycle carve into the dense molecular cloud of hydrogen. Both the outflows and the star’s light energize the gas, causing it to glow. While much of this hydrogen gas is blown away, a large amount is also compressed, creating the conditions for even more stars to form.

RIP: NASA Software Engineer Margaret Hamilton

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Image (Credit): Margaret Hamilton at MIT. (NASA)

Late last month, Margaret Hamilton passed away at the age of 90. She will always be remembered as the software engineer who was instrumental in the development of the flight software for NASA’s Apollo program. As a NASA contractor from the Software Engineering Division of the MIT Instrumentation Laboratory, she led a team of 100 engineers. Her work in this area helped to establish software engineering as a dedicated discipline

Olivier de Weck, the Apollo Program Professor and interim head of the MIT Department Aeronautics and Astronautics, later stated:

The Apollo program still stands as one of our greatest testaments to the power of collaboration, ingenuity, and engineering, and Margaret Hamilton was a fundamental contributor to that program’s success. And for her that was just the beginning! She went on to become an entrepreneur and remained on the cutting edge of systems software throughout an extraordinary career, while acting as an advocate, mentor, and inspiration to millions.

You can read more on Ms. Hamilton’s life and career at these sites:

MIT
CNN
The New York Times

Rest in peace.