Near IR variability of the quiet Sun

Abstract

The IR region of the solar spectrum provides important diagnostics for heat transfer processes in the photosphere, where the gravity and acoustic waves which heat the corona originate. Rates of molecule formation and dissociation in these layers are highly temperature sensitive. Recently relative intensities and short-period variations in individual lines of the rotation–vibration band of CO at 4.7 µm (refs 1–3) were obtained with spectral resolution ν/Δν∼0.7−2.1×10⁴ (refs. 4, 5) from ground-based sites. High resolution cannot wholly overcome atmospheric absorption problems, so to measure absolute energy and variability in the band we have observed the solar spectrum from the orbital station Salyut 5.