Astrodynamics Simulation and Orbital analysis of the LHS 1903 planetary system.
Abstract
I independently investigated the orbital dynamics of the LHS 1903 planetary system, a four-planet system orbiting an M-type red dwarf approximately 116 light-years from Earth. The system is particularly interesting because of its compact architecture and the different planetary types and orbital distances within the system. I used published planetary parameters from the NASA Exoplanet Archive and implemented them in NASA's General Mission Analysis Tool (GMAT) to investigate the system's orbital behaviour over time. Method I obtained published orbital parameters for LHS 1903b, c, d and e and converted the relevant quantities into formats compatible with GMAT. The simulation incorporated: Semi-major axes Orbital eccentricities Planetary masses Inclination Right ascension of the ascending node Argument of periapsis True anomaly Because GMAT does not allow the creation of an arbitrary star as a central celestial object in the configuration I used, I represented LHS 1903 using the default Sun object and assigned it the relevant properties of the LHS 1903 star. The planets were configured as satellites of this central body, and their trajectories were propagated using GMAT's numerical modelling capabilities. For orbital parameters that are not fully constrained observationally, standard reference values were assumed to construct a consistent initial configuration. Results The system was propagated for approximately 167 simulated years. During the simulation: All four planets maintained their orbital trajectories. No orbital crossings were observed. No obvious instability events occurred. The orbital elements remained largely unchanged over the simulated period. The planets maintained nested orbital paths around the host star. The results therefore indicate that the modeled system remained dynamically stable over the simulated short-term timescale. Limitations The simulation is not intended to establish that LHS 1903 is stable over geological or astronomical timescales. Important limitations include: The simulation duration was only approximately 167 years. Several orbital-orientation parameters were assumed because they are not fully constrained for the planets. The model used point-mass representations. Relativistic effects were not included. Stellar activity was not modeled. The model does not establish long-term stability over millions or billions of years. Therefore, the current result should be interpreted as evidence of stability within the specific simulated configuration and timescale, rather than as a definitive prediction of the system's long-term evolution. Future Research I would like to develop this project further by investigating: Much longer numerical integrations. The influence of different assumed orbital orientations. Possible orbital resonances between planets. The sensitivity of stability to variations in the published orbital parameters. Improved physical modelling of the host star and planetary interactions. Whether the apparent stability persists under substantially different initial conditions. Motivation for Further Research This project began as an independent investigation into whether a real exoplanetary system could be studied computationally using publicly available astronomical data. I am now interested in taking the work beyond an independent simulation and learning how professional researchers approach planetary-system dynamics, numerical modelling, uncertainty, and the interpretation of simulation results. I would particularly value the opportunity to work under the guidance of a researcher in exoplanetary science, planetary-system dynamics, or computational astrophysics.
Description / Details
Over the past couple months I have been investigating the Orbital Stability of the recently discovered Exoplanetary system, LHS1903, using NASA's General Mission Analysis Tool.
Research Question: To what extent is the LHS 1903 planetary system dynamically stable over short-term timescales when modeled using Newtonian N-body gravitational simulations?
I obtained the available orbital parameters from the NASA Exoplanet Archive and implemented them into a GMAT simulation. I then monitored the orbital trajectories and orbital elements over approximately 167 years of simulated time.
The simulation showed no orbital crossings or obvious instability during the simulated period.
However, I want to be very clear about the limitations of the work. Several orbital orientation parameters had to be assumed because they are not fully constrained observationally, and the simulation does not include effects such as relativistic corrections, stellar activity, or tidal forces. Most importantly, 167 years is extremely short compared with astronomical timescales.
So I’m not presenting this as a definative prediction of long term stability of the LHS 1903.
Instead, I’m sharing it because I’d genuinely like to learn from people who work in astrophysics, astrodynamics, and planetary dynamics.
If you are a researcher, professor, or student working in this area, I would especially appreciate feedback on:
• The validity of my simulation methodology
• My treatment of the orbital parameters
• Whether my interpretation of “stability” is appropriate
• Important physical effects I should include in a future model
• Ways I could make the analysis more rigorous
This is my first research project, so I’m particularly interested in any way I can improve myself, and work towards more detailed research.
Below is the attached file with the full paper.
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Sep 27, 2026
Research Paper
Astrophysics
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