We present a study of the terrestrial hydroxyl nightglow emissions observed with the Visible and Infrared Thermal Imaging Spectrometer on board the Rosetta mission. During these observations, the OH ?v=1 and 2 sequences were measured simultaneously. This allowed investigating the relative population of the v=1 to 9 vibrational levels by using both sequences. In particular, the relative population of the vibrational level v=1 is determined for the first time from observations. The vibrational population decreases with increasing vibrational quantum number. A good agreement is found with a recent model calculation assuming multiquantum relaxation for OH(v) quenching by O<inf>2</inf> and single-quantum relaxation for OH(v) by N<inf>2</inf>. Key Points Earth OH(?v=1, 2) emissions are studied simultaneously with VIRTIS/Rosetta Relative OH population values for v=1 to 9 are derived from measurements Comparison with previous observations and models are provided.
Terrestrial OH nightglow measurements during the Rosetta flyby
Snels M;
2015
Abstract
We present a study of the terrestrial hydroxyl nightglow emissions observed with the Visible and Infrared Thermal Imaging Spectrometer on board the Rosetta mission. During these observations, the OH ?v=1 and 2 sequences were measured simultaneously. This allowed investigating the relative population of the v=1 to 9 vibrational levels by using both sequences. In particular, the relative population of the vibrational level v=1 is determined for the first time from observations. The vibrational population decreases with increasing vibrational quantum number. A good agreement is found with a recent model calculation assuming multiquantum relaxation for OH(v) quenching by OI documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
