Detection of Mercury's Potassium Tail - Archive ouverte HAL Access content directly
Conference Papers Year :

Detection of Mercury's Potassium Tail

(1) , (2) , (3) , (4)
1
2
3
4

Abstract

Ground-based observations of Mercury's exosphere bridge the gap between the MESSENGER and BepiColombo missions and provide a broad counterpart to their in situ measurements. Here we report the first detection of Mercury's potassium tail in both emission lines of the D doublet. The sodium to potassium abundance ratio at 5 planetary radii down-tail is approximately 95, near the mid-point of a wide range of values that have been quoted over the planet's disk. This is several times the Na/K present in atmospheres of the Galilean satellites and more than an order of magnitude above Mercury's usual analogue, the Moon. The observations confirm that Mercury's anomalously high Na/K ratios cannot be explained by differences in neutral loss rates. The width and structure of the Na and K tails is comparable and both exhibit a persistent enhancement in their northern lobe. We interpret this as a signature of Mercury's offset magnetosphere; the exosphere's source rates are locally enhanced at the southern surface, and sloshing from radiation pressure and gravity guides this population into the northern region of the tail.
Not file

Dates and versions

insu-01664385 , version 1 (14-12-2017)

Identifiers

Cite

Carl Schmidt, François Leblanc, Luke Moore, Thomas A. Bida. Detection of Mercury's Potassium Tail. 49th Annual Division for Planetary Sciences Meeting, Oct 2017, Provo, United States. ⟨insu-01664385⟩
254 View
0 Download

Share

Gmail Facebook Twitter LinkedIn More