^1,2A. G. J. Jurewicz,³A. M. Amarsi,⁴D. S. Burnett,^5,6N. Grevesse
Meteoritics & Planetary Science (in Press) Open Access Link to Article [https://doi.org/10.1111/maps.14272]
¹School of Earth and Space Exploration, Arizona State University Busek Center for Meteorite Studies, Tempe, Arizona, USA
²Department of Earth Science, Dartmouth College, Hanover, New Hampshire, USA
³Theoretical Astrophysics, Department of Physics and Astronomy, Uppsala University, Uppsala, Sweden
⁴Department of Geology and Planetary Sciences, California Institute of Technology, Pasadena, California, USA
⁵Centre Spatial de Liège, Université de Liège, Liège, Belgium
⁶STAR Institute, Université de Liège, Liège, Belgium
Published by arrangement with John Wiley & Sons

CI chondrites have been a proxy for the solar system since the mid-20th century. The photospheric and CI chondrite abundances (P and CI, respectively) show a strong correlation. CI as a proxy is also justified by the (i) smoothness of their abundances plotted as a function of odd mass number and (ii) agreement within the error of P as determined spectroscopically. But our statistical assessment of spectroscopic studies and solar wind from the Genesis mission indicates that the small, ~10%–30%, differences (residuals) between CI and P depend on the 50% condensation temperature (Tc50). So, if CI is to be used as a proxy for P, Cosmochemists may want to add a correction to individual elements. Our work is consistent with two published hypotheses: that (i) residuals are linear with Tc50 and (ii) that elements having Tc50 > 1343 K are depleted relative to those with 495 K < Tc50 < 1343 K in CI. We discuss other interpretations which are also feasible. Understanding these small differences of the CI and P for different elements and their variation with Tc50 can help constrain future models of solar system formation and the history of CI chondrites.