English (United Kingdom)

https://curated-unify.zendy.io/wp-json/zendy-region/v1/featured_content/oa?rat=en

https://curated-unify.zendy.io/wp-json/zendy-region/v1/highlighted_journal/

Global: Zendy Plus annual

Presents the access of premium content as premium feature

Premium Content

Presents the keyphrase highlighting as premium feature

Keyphrase Highlighting

Presents the summarisation as premium feature

Summarisation

Insights

Presents the pdf analysis as premium feature

PDF Analysis

Presents the zaia usage as premium feature

ZAIA

Global: Zendy Tools annual

Global: Zendy Free Plan

Global: Zendy Tools monthly

Global: Zendy Plus monthly

We present three near-infrared spectra of Pluto taken with the IRTF and SpeX,an optical spectrum of Triton taken with the MMT and the Red ChannelSpectrograph, and previously published spectra of Pluto, Triton, and Eris. Wecombine these observations with a two-phase Hapke model, and gain insight intothe ice mineralogy on Pluto, Triton, and Eris. Specifically, we measure themethane-nitrogen mixing ratio across and into the surfaces of these icy dwarfplanets. In addition, we present a laboratory experiment that demonstrates itis essential to model methane bands in spectra of icy dwarf planets with twomethane phases - one highly-diluted by nitrogen and the other rich in methane.For Pluto, we find bulk, hemisphere-averaged, methane abundances of 9.1 \pm0.5%, 7.1 \pm 0.4%, and 8.2 \pm 0.3% for sub-Earth longitudes of 10\degree,125\degree, and 257\degree. Application of the Wilcoxon rank sum test to ourmeasurements finds these small differences are statistically significant. ForTriton, we find bulk, hemisphere-averaged, methane abundances of 5.0 \pm 0.1%and 5.3 \pm 0.4% for sub-Earth longitudes of 138\degree and 314\degree.Application of the Wilcoxon rank sum test to our measurements finds thedifferences are not statistically significant. For Eris, we find a bulk,hemisphere-averaged, methane abundance of 10 \pm 2%. Pluto, Triton, and Eris donot exhibit a trend in methane-nitrogen mixing ratio with depth into theirsurfaces over the few cm range probed by these observations. This result iscontrary to the expectation (Grundy & Stansberry 2000) that since visible lightpenetrates deeper into a nitrogen-rich surface than the depths from whichthermal emission emerges, net radiative heating at depth would drivepreferential sublimation of nitrogen leading to an increase in the methaneabundance with depth.

Ice Mineralogy Across and Into the Surfaces of Pluto, Triton, and Eris