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Solar Carbon Monoxide, Thermal Profiling, and the Abundances of C, O, and their Isotopes

Thomas R. Ayres·Claude Plymate·Christoph U. Keller
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Abstract

A solar photospheric "thermal profiling" analysis is presented, exploiting the infrared rovibrational bands of carbon monoxide (CO) as observed with the McMath-Pierce Fourier transform spectrometer (FTS) at Kitt Peak, and from above the Earth's atmosphere by the Shuttle-borne ATMOS experiment. Visible continuum intensities and center-limb behavior constrained the temperature profile of the deep photosphere, while CO center-limb behavior defined the thermal structure at higher altitudes. The oxygen abundance was self consistently determined from weak CO absorptions. Our analysis was meant to complement recent studies based on 3-D convection models which, among other things, have revised the historical solar oxygen (and carbon) abundance downward by a factor of nearly two; although in fact our conclusions do not support such a revision. Based on various considerations, an oxygen abundance of 700+/-100 ppm (parts per million relative to hydrogen) is recommended; the large uncertainty reflects the model sensitivity of CO. New solar isotopic ratios also are reported for 13C, 17O, and 18O.

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Thomas R. Ayres, Claude Plymate, Christoph U. Keller. 2006-06-07. Solar Carbon Monoxide, Thermal Profiling, and the Abundances of C, O, and their Isotopes. https://doi.org/10.1086/504847

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