EGU2020-7143, updated on 14 May 2024
https://doi.org/10.5194/egusphere-egu2020-7143
EGU General Assembly 2020
© Author(s) 2024. This work is distributed under
the Creative Commons Attribution 4.0 License.

Space weather at Mercury as observed by the THEMIS telescope from Earth

Melinda Dósa1, Valeria Mangano2, Anna Milillo2, Stefano Massetti2, Zsofia Bebesi1, and Anikó Timár1,3
Melinda Dósa et al.
  • 1Wigner Research Centre for Physics, Space Physics and Space Technology, Budapest, Hungary (dosa.melinda@wigner.mta.hu)
  • 2INAF/IAPS, Istituto Nazionale di Astrofisica, Roma, Italy
  • 3Department of Geophysics and Space Science, Eötvös Loránd University, Budapest, Hungary

The dynamic changes of Mercury’s Na exosphere are investigated here, in relation to space weather conditions. Sodium plays a special role in Mercury’s exosphere: due to its strong resonance D lines at 5890-95Å it has been observed and monitored by Earth-based telescopes for decades. Different and highly variable patterns of Na-emission have been identified. In addition to the release processes already studied extensively in the past, we aim here to investigate the following factors more in detail: the distance to the Sun, position in relation to the ecliptic plane and solar wind magnetic field strength and direction. In order to better investigate the relationship of these factors, we have studied the intensity of Na-emission as a function of solar wind dynamic pressure and TAA of Mercury by means of the extended dataset images collected from 2009 to 2013 by Earth-based observations performed at the THEMIS solar telescope. Solar wind velocity and density values are propagated with the magnetic lasso method to the position of Mercury from nearby space probes and compared with Na emission intensity. Data of either ACE or one of the two STEREO spacecraft were used, depending on which spacecraft had a smaller angular distance to Mercury. Single cases are studied qualitatively, and a longer-term quantitative comparison is shown, including further parameters (solar wind magnetic field strength and direction, TAA).

How to cite: Dósa, M., Mangano, V., Milillo, A., Massetti, S., Bebesi, Z., and Timár, A.: Space weather at Mercury as observed by the THEMIS telescope from Earth, EGU General Assembly 2020, Online, 4–8 May 2020, EGU2020-7143, https://doi.org/10.5194/egusphere-egu2020-7143, 2020.

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