In contrast, Sheila’s analysis of M-dwarfs does not detect this feature. The M-dwarf sample size is small (236 planets), so non-detection is not necessarily evidence of non-existence. Nevertheless, giant planets are rare around small stars, so there is reason to think the trend could be real.

We do see one difference though. My analysis of FGK stars detected tentative (2-sigma) evidence for elevated eccentricies in the so-called exoplanet radius valley, which we hypothesize arises from giant impacts mediated by giant planets.

The straightforward conclusion is that the astrophysics of planet formation are largely similar for cool stars (M-dwarfs) compared to more Sun-like stars (FGK dwarfs).

Now, UF graduate student Sheila Sagear has demonstrated that the same trends hold for planets orbiting smaller M-dwarf stars.

A conspicuous eccentricity rise at approximately 3.5 Earth-radii also coincides with known transitions in occurrence rates and host star metallicities, providing clues to formation physics.

The eccentricity-radius relation holds for both single-transiting and multi-transiting systems, suggesting these singles and multis belong to the same parent population.

A few months ago, I published a paper demonstrating that planets larger than Neptune have elevated orbital eccentricities compared to smaller planets. Our analysis measured eccentricities for 1646 transiting planets orbiting FGK stars, by far the largest sample of exoplanet eccentricities to-date.

Want to learn about the relationship between planet size and orbital eccentricity? Read this thread! 🧪 🔭 🪐