On the widths of the Mg X lines near 60 nm in the corona

We examine the line widths of both components of the Mg x 2s S-2(1/2)-2p(2)P(1/2,3/2) doublet at 60.98 nm and 62.50 nm in the low corona of the quiet Sun, and find that the Doppler width (i.e. half 1/e width) broadens from Deltalambda(D) approximate to 8.2 pm to approximate to 9.5 pm (with an estimated relative standard uncertainty of 4%) between the limb and 220 Mm above the limb in the equatorial corona. In a polar coronal hole, the Doppler width increases from 10.8 pm near 30 Mm to 11.4 pm at around 80 Mm. The analysis does not provide any evidence for a narrowing of the emission-line profiles as a function of the distance from the solar limb.