A team from the Southwest Research Institute (SwRI) has merged compositional data from ancient celestial bodies such as Kuiper Belt objects, asteroids, and comets with the latest solar datasets. This effort led to a new understanding of solar composition, which may harmonize results from spectroscopy and helioseismology for the first time. While helioseismology explores the interior of the Sun by studying waves that traverse it, spectroscopy analyzes the surface makeup by looking at the spectral signatures of various chemical elements.
A team from the Southwest Research Institute (SwRI) has merged compositional data from ancient celestial bodies such as Kuiper Belt objects, asteroids, and comets with the latest solar datasets. This effort led to a new understanding of solar composition, which may harmonize results from spectroscopy and helioseismology for the first time. While helioseismology explores the interior of the Sun by studying waves that traverse it, spectroscopy analyzes the surface makeup by looking at the spectral signatures of various chemical elements.
A research paper detailing these findings, which addresses the long-standing issue of “solar abundances,” has been published in the AAS Astrophysical Journal.
“This is the first time such interdisciplinary analysis has been conducted, and our extensive data suggests that the levels of solar carbon, nitrogen, and oxygen are more abundant than previously believed,” explained Dr. Ngoc Truong, a postdoctoral researcher at SwRI. “Models of solar system formation utilizing our updated solar composition effectively replicate the compositions of large Kuiper Belt objects (KBOs) and carbonaceous chondrite meteorites, especially in light of the fresh samples returned from Ryugu and Bennu by JAXA’s Hayabusa-2 and NASA’s OSIRIS-REx missions.”
To reach this conclusion, the research team combined new measurements of solar neutrinos and data on the solar wind’s composition from NASA’s Genesis mission, along with the water abundance found in primitive meteorites from the outer solar system. They also considered the densities of significant KBOs like Pluto and its moon Charon, as determined by NASA’s New Horizons mission.
“This research offers testable predictions for future helioseismology studies, solar neutrino observations, and cosmochemical measurements, including upcoming comet sample return missions,” said Truong. “The updated solar composition serves as a calibration tool for other stars, aiding in understanding the making of solar system objects. These advancements will deepen our knowledge of the primordial solar nebula’s chemical makeup and the formation processes of various solar system bodies.”
The team investigated the importance of refractory, tar-like organic compounds as a key carrier of carbon within the protosolar nebula. Previous solar system formation models that used organic measurements from comet 67P/Churyumov-Gerasimenko and previous solar composition ratios failed to explain the dense, rocky system of Pluto and Charon.
“Through this research, we believe we finally grasp the mix of chemical elements responsible for the solar system’s formation,” stated Dr. Christopher Glein from SwRI, who specializes in planetary geochemistry. “It reveals higher levels of carbon, nitrogen, and oxygen than we currently assume, providing a stronger basis for understanding what element abundances in giant planet atmospheres indicate about planet formation. We are already focusing on Uranus — NASA’s next target — and beyond.”
In the quest to identify habitable exoplanets, scientists assess the elemental abundances in stars through spectroscopy to infer the compositions of the planets orbiting them, using the stellar composition as a reference.
“Our results will greatly influence our understanding of the formation and evolution of other stars and planetary systems. They also allow for a broader perspective on galactic chemical evolution,” Truong noted.
One scientist associated with Cornell University contributed to this research, which was funded by SwRI’s Internal Research and Development program and the Heising-Simons Foundation.
