Properties of the Sun ’ s interior can be determined accurately from helioseismological measurements of solar oscillations .
These measurements , however , are in conflict with photospheric elemental abundances derived using 3-D hydrodynamic models of the solar atmosphere .
This divergence of theory and helioseismology is known as the `` solar modeling problem " .
One possible solution is that the photospheric neon abundance , which is deduced indirectly by combining the coronal Ne/O ratio with the photospheric O abundance , is larger than generally accepted .
There is some support for this idea from observations of cool stars .
The Ne/O abundance ratio has also been found to vary with the solar cycle in the slowest solar wind streams and coronal streamers , and the variation from solar maximum to minimum in streamers ( \sim 0.1 to 0.25 ) is large enough to potentially bring some of the solar models into agreement with the seismic data .
Here we use daily-sampled observations from the EUV Variability Experiment ( EVE ) on the Solar Dynamics Observatory taken in 2010–2014 , to investigate whether the coronal Ne/O abundance ratio shows a variation with the solar cycle when the Sun is viewed as a star .
We find only a weak dependence on , and moderate anti-correlation with , the solar cycle with the ratio measured around 0.2–0.3 MK falling from 0.17 at solar minimum to 0.11 at solar maximum .
The effect is amplified at higher temperatures ( 0.3–0.6 MK ) with a stronger anti-correlation and the ratio falling from 0.16 at solar minimum to 0.08 at solar maximum .
The values we find at solar minimum are too low to solve the solar modeling problem .