Stability in Exoplanets

The Kepler and TESS space telescopes have discovered thousands of planets orbiting distant stars. However, it is still very much a mystery (i) how these exoplanetary systems came to form and (ii) how do they remain in stable orbits for billions of years. Below I summarize a paper that I worked on that employed a massive parameter search to simulate stable orbits of observed exoplanetary systems and understand the physical properties of the planets involved.

Figure 1

Shown to the left is a visualization of the radial velocity (RV) method for detecting exoplanets. We modeled RV data of exoplanetary system HD 200964.

Figure 2

RV data from exoplanetary system HD 200964. Our models confirmed that this system consists of two Jupiter sized planets with orbital periods of ~600 and 800 days.

Figure 3

One of the most difficult problems with modeling exoplanetary orbits is keeping the planets on stable orbits for > billion years. We attempted to tackle this problem with a Markov Chain Monte Carlo grid search (left) to fit the RV data with physical parameters of the orbit e.g., planet masses, periods, eccentricities etc. We were able to recover long term stability for HD 200964 and discovered the ratio of orbital periods (resonance) is an essential element in simulating stable orbits.