Presentation #102.229 in the session Poster Session.
The recent discovery of a gap dividing the solar system’s protoplanetary disk (SS’s PPD) into two peaks is further evidence of the peak-gap-peak (PGP) feature found in the distribution of semi-major axes of exoplanets hosted by stars that are most like the sun in mass, being single, and in having the same or higher metallicity. The exoplanet PGP feature was published before presentation of the gap in the SS’s PPD. It has long been thought that PPDs form with separate inner and outer disks separated by a gap, but seeing this structure in the distribution of exoplanet semi-major axes was unexpected because it had been thought that primordial features are erased by subsequent planet migration. This gap is present for planets of single stars, but appears partially filled for planets of stars with stellar companions. The gap in the solar system’s PPD is reported to be closer than 3 AU, while for planets of solar-mass stars the gap in exoplanet semi-major axes extends from the end of an inner peak at 1.5 AU to the sudden dramatic pileup starting at 1.9 AU. The two results taken together suggest that planets of stars that are similar to the sun or with higher metallicity may generally start their evolution with a gap in this range, likely associated with a snow line. We are now reporting finding that the semi-major axis of this feature appears to scale with the square root of stellar mass.
To best promote study of features of the distribution of exoplanets, we propose that the study of planetary system architectures and demographics be organized in the form of a new additional section of an exoplanet catalog, which would include results on exoplanet occurrence distributions and findings of features and correlations among exoplanet parameters.