Mercury’s Sodium Exosphere: Anab initioCalculation to InterpretMASCS/UVVS Observations from MESSENGER

Gamborino, Diana; Vorburger, Audrey; Wurz, Peter (2018). Mercury’s Sodium Exosphere: Anab initioCalculation to InterpretMASCS/UVVS Observations from MESSENGER. Annales geophysicae discussions, pp. 1-24. Copernicus Publications 10.5194/angeo-2018-109

[img]
Preview
Text
angeo-2018-109.pdf - Published Version
Available under License Creative Commons: Attribution (CC-BY).

Download (2MB) | Preview

The optical spectroscopy measurements of sodium in Mercury’s exosphere by MESSENGER MASCS/UVVS have been interpreted before with a model employing two exospheric components of different temperatures. Here we use an updated version of the Monte Carlo (MC) exosphere model developed by Wurz and Lammer (2003) to calculate the Na content of the exosphere for the observation conditions. In addition, we compare our results to the ones according to Chamberlain theory. Studying several release 5 mechanisms, we find that close to the surface thermal desorption dominates driven by a surface temperature of 594 K, whereas at higher altitudes micro-meteorite impact vaporization prevails with a characteristic energy of 0.34 eV. From the surface up to 500 km the MC model results agree with the Chamberlain model, and both agree well with the observations. At higher altitudes, the MC model using micro-meteorite impact vaporization explains the observation well. We find that the combination of thermal desorption and micro-meteorite impact vaporization reproduces the observation of the 10 selected day quantitatively over the entire observed altitude range, with the calculations performed based on the prevailing environment and orbit parameters. These findings may help to improve our understanding of the physical conditions at Mercury’s exosphere, as well as to better interpret mass-spectrometry data obtained to date and in future missions, such as BepiColombo.

Item Type:

Journal Article (Original Article)

Division/Institute:

08 Faculty of Science > Physics Institute > Space Research and Planetary Sciences
08 Faculty of Science > Physics Institute

UniBE Contributor:

Gamborino Uzcanga, Diana; Vorburger, Audrey Helena and Wurz, Peter

Subjects:

500 Science > 520 Astronomy
600 Technology > 620 Engineering
500 Science > 530 Physics

ISSN:

2568-6402

Publisher:

Copernicus Publications

Language:

English

Submitter:

Dora Ursula Zimmerer

Date Deposited:

19 Sep 2019 13:19

Last Modified:

19 Sep 2019 13:19

Publisher DOI:

10.5194/angeo-2018-109

BORIS DOI:

10.7892/boris.130426

URI:

https://boris.unibe.ch/id/eprint/130426

Actions (login required)

Edit item Edit item
Provide Feedback