Production of N₂ Vegard–Kaplan and Lyman–Birge–Hopfield emissions on Pluto

Abstract

We have developed a model to calculate the emission intensities of various vibrational transitions of N₂ triplet band and Lyman–Birge–Hopfield (LBH) band emissions in the dayglow of Pluto for solar minimum, moderate, and maximum conditions. The calculated overhead intensities of Vegard–Kaplan (A³Σ_u+–X¹Σ_g⁺), First Positive (B³Π_g–A³Σ_u⁺), Second Positive (C³Π_u–B³Π_g), Wu–Benesch (W3Δu(W3Δu–B3Πg)B3Πg), Reverse First Positive, and LBH (a¹Π_g–X¹Σ_g⁺) bands of N₂ are 17 (74), 14.8 (64), 2.4 (10.8), 2.9 (12.7), 2.9 (12.5), and 2.3 (10) R, respectively, for solar minimum (maximum) condition. We have predicted the overhead and limb intensities of VK (150–190 nm) and LBH (120–190 nm) bands of N₂ on Pluto for the New Horizons (NH) flyby condition that can be observed by ALICE: the ultraviolet imaging spectrograph also know as P-ALICE. The predicted limb intensities of VK and LBH bands peak at radial distance of ∼2000 km with the value of about 5 (13) and 9.5 (22) R for solar zenith angle 60° (0°), respectively. We have also calculated overhead and limb intensities of few prominent transition of CO Fourth Positive bands for NH flyby condition.