Nitrogen on Triton and Pluto

[摘要] NOTE: Text or symbols not renderable in plain ASCII are indicated by [...]. Abstract is included in .pdf document.Nitrogen has been detected on the surfaces of two objects in the solar system, Triton and Pluto. To better understand the surfaces of these two bodies I have made measurements of the spectrum of solid nitrogen at temperatures applicable to Triton and Pluto, over a wavelength region which encompasses both the fundamental vibrational transition of N2, at 4.294 [...], and its first overtone, at 2.148 [...]. These measurements show that the appearance of the N2 bands is a function of temperature. I have used this temperature dependence, in conjunction with observational data and spectral modeling techniques, to determine the temperature of N2 on Triton and Pluto. The temperature I derive for Triton, 38±1 K, is in agreement with measurements made by the Voyager 2 spacecraft. The temperature determined for Pluto is 40±2 K, slightly warmer than for Triton. Observations of Pluto's thermal flux have not been able to constrain Pluto's temperature well; estimates in the literature run from 30 to 60 K. To determine if the spectroscopically derived temperature for nitrogen on Pluto is consistent with the published thermal fluxes of Pluto I have modeled the expected thermal flux assuming that the N2 is contained in symmetric polar caps and that the equatorial region is bare of nitrogen. With these assumptions I find that the modeled flux of Pluto fits all the published thermal flux measurements if the polar caps extend to ±20° latitude, and if the equatorial region has a bolometric albedo [...] 0.2.

[发布机构] University:California Institute of Technology;Department:Geological and Planetary Sciences

[关键词] Planetary Science and Astronomy