Full Breakdown
Revised Solar Silver Abundance: 55 % Higher Than Previously Estimated
7/25/2026, 11:14:55 AM
Core Findings
A research team led by Sema Caliskan has determined that the Sun’s silver content is about 55 % greater than the value used for the past decade. By applying a three-dimensional, non-equilibrium model of the solar atmosphere and recalculating the atomic physics of silver, the team derived a new solar silver abundance that aligns closely with the levels measured in primitive CI chondrite meteorites.
Background & Context
Earlier spectroscopic analyses, based on a simplified assumption of local thermodynamic equilibrium, indicated that the Sun contained markedly less silver than CI chondrites—meteorites formed from the same primordial cloud 4.6 billion years ago. The 2015 solar photospheric value left a ~78 % discrepancy with meteoritic measurements, a mismatch that persisted through a 2021 solar-chemistry census. Because solar abundances serve as the reference yardstick for all other stars, resolving this inconsistency was critical for studies of Galactic chemical evolution.
Methodology and Modeling Advances
The researchers measured the Sun’s silver by examining two ultraviolet absorption lines at 328 nm and 338 nm. Their new approach combined:
- A dynamic three-dimensional model of the Sun’s outer layers, replacing the earlier one-dimensional column.
- Non-equilibrium effects, accounting for ultraviolet photons that continuously excite silver atoms and collisions that further alter energy-level populations.
- An expanded atomic dataset covering 57 energy levels and 183 transitions, with 53 of those transitions calculated theoretically.
Calculations were performed on Tetralith, a Swedish supercomputer at the National Supercomputer Center in Linköping. By switching off the silver lines’ absorbing power within the model, the team confirmed that the revised line strengths were responsible for the higher abundance estimate.
Data & Statistics
- The revised model yields a 55 % net increase over the 2015 solar silver figure.
- The earlier ~78 % gap between solar and meteoritic silver shrinks to ~15 %, a difference that falls within combined uncertainties.
- Incorporating the full three-dimensional, non-equilibrium treatment produces a 91 % increase relative to the simplest model, with most of the rise driven by abandoning the equilibrium assumption.
Official Statements & Responses
She noted that the team did not fine-tune the model to match meteoritic values, allowing the physics alone to bring the Sun into agreement with primitive meteorites. The authors also announced plans to apply the same methodology to a broader range of stellar types.
Why It Matters
Solar elemental abundances underpin comparative analyses of stellar populations and Galactic chemical evolution. A more accurate silver abundance improves the reliability of silver-to-iron trends used to trace the rapid neutron-capture process in the Galaxy’s history. The researchers have released correction tables for dwarf and giant stars, enabling other astronomers to adjust their silver measurements without running full three-dimensional simulations.
Verbatim Quotes
- “The new knowledge about the Sun's composition is important for the understanding of other stars, planets and cosmic material, because the Sun is one of astronomy's key reference points,” — Sema Caliskan
What’s Next
The team will extend the modeling framework to other heavy elements and to stars of varying ages and metallicities. By publishing correction tables for a grid of model atmospheres, they invite the broader community to re-evaluate silver abundances in both dwarf and giant stars, potentially refining the Milky Way’s chemical-evolution timeline.
