ExPRES AD Leonis Radio Emission Simulations Data Collection

• DOI: 10.25935/2zbg-6s07
• Publisher: PADC
• License: CC-BY 4.0
• Citation: Louis, C. K. & Zarka, P. (2025). ExPRES AD Leonis Radio Emission Simulations Data Collection (Version 1.0) [Data set]. PADC. https://doi.org/10.25935/2zbg-6s07

Link to data repository

• Data Products

Data directories are hierarchically organised by beaming thickness width, beaming pattern beaming and by hemisphere hemisphere. See the Description section below for more details.

Description

This data collection contains pre-computed ExPRES simulation runs for the Red Dwarf AD Leonis used in Zarka et al. (2025), with with various parameter sets:

• Magnetic Field Model (based on Bellotti et al., 2023):
  • magnetic dipole of moment 461.5 G.R_* ³ (i.e., an equatorial surface field of 461.5 G),
  • centred on the star’s center,
  • inclined at 59° from the rotation axis, itself at ∼20° from the line of sight, with the magnetic south pole in the hemisphere visible for a terrestrial observer.
  • The star rotates in 2.23 days.
• Beaming thickness width: 0.5°, 1° or 2°
• CMI Mechanism that controls the beaming pattern beaming: Loss Cone or Shell, or beaming with a constant values (85° or 90°)
• Electron energy: 5, 10, 20, 30, 100, 200 or 500 keV.
• In RX or LO mode.
• 360 sources are set every degree of longitude at L-Shell 2, 5, 10, 20 or 40 R_*.
• The observer is set at Earth.
• Simulated frequencies range from 1 to 1700 MHz.
• ExPRES Version 1.3 (Louis et al. 2023) was used.

Note that:

1. the typical beaming thickness is 1° and that the other 2 (0.5 and 2) are to check the consistency of the results;
2. simulations are separated by hemisphere hemisphere

AD Leo being a relatively cool star, its coronal plasma density likely drops rapidly above the
photosphere and the ambient plasma frequency is likely smaller than the simulated frequency. As a consequence, we neglect near-source refraction and thus we assume straight line propagation from the radio source to the terrestrial observer

The data files contain the modelled following parameters: polarization, theta, CML (obs longitude), obs latitude, obs distance, srcfreqmax, srcLongitude, fc (detailed informations are available in Louis et al., 2019).

The data files are provided in CDF format, and the ExPRES input files are JSON files.

Coverage

• 2021-12-02 20:00 to 2021-12-03 23:59.

Acknowledgments
The authors acknowledge funding from the ERC under the European Union’s Horizon 2020 research and innovation program (grant agreement no 101020459 - Exoradio)

References

• Bellotti, S., J. Morin, L. T. Lehmann, C. P. Folsom, G. A. J. Hussain, P. Petit, J.-F. Donati, A. Lavail, A. Carmona, E. Martioli, B. Romano Zaire, E. Alecian, C. Moutou, P. Fouqué, S. Alencar, E. Artigau, I. Boisse, F. Bouchy, C. Cadieux, R. Cloutier, N. J. Cook, X. Delfosse, R. Doyon, G. Hébrard, O. Kochukhov and G. A. Wade (2023). Monitoring the large-scale magnetic field of AD Leo with SPIRou, ESPaDOnS, and Narval - Towards a magnetic polarity reversal? A&A, 676, A56, https://doi.org/10.1051/0004-6361/202346845
• Louis, C K, S L G Hess, B Cecconi, P Zarka, L Lamy, S Aicardi, and A Loh. 2019. “ExPRES: an Exoplanetary and Planetary Radio Emissions Simulator.” Astronomy and Astrophysics 627 (May): A30. doi:10.1051/0004-6361/201935161.
• Louis, C. K., Hess, S. L. G., Cecconi, B., Zarka, P., Lamy, L., Aicardi, S., & Loh, A. (2023). maserlib/ExPRES: Version 1.3.0 (1.3.0). Zenodo. https://doi.org/10.5281/zenodo.7759484
• Zarka P., C. K. Louis, J. Zhang, H. Tian, J. Morin, Y. Gao (2025), "Location and energy of electrons producing the radio bursts from AD Leo observed by FAST in December 2021", Astronomy and Astrophysics. Preprint: https://arxiv.org/abs/2501.16180