Debiasing the Minimum-mass Extrasolar Nebula: On the Diversity of Solid Disk Profiles

A foundational idea in the theory of in situ planet formation is the "minimum-mass extrasolar nebula" (MMEN), a surface density profile (Sigma) of disk solids that is necessary to form the planets in their present locations. While most previous studies have fit a single power law to all exoplanets in an observed ensemble, it is unclear whether most exoplanetary systems form from a universal disk template. We use an advanced statistical model for the underlying architectures of multiplanet systems to reconstruct the MMEN. The simulated physical and Kepler-observed catalogs allow us to directly assess the role of detection biases, and in particular the effect of nontransiting or otherwise undetected planets, in altering the inferred MMEN. We find that fitting a power law of the form Sigma = Sigma(0)* (a/a(0))(beta) to each multiplanet system results in a broad distribution of disk profiles; Sigma(0)* = 336(-291)(+727) g cm(-2) and beta = -1.98(-1.52)(+1.55 )encompass the 16th-84th percentiles of the marginal distributions in an underlying population, where Sigma(0)* is the normalization at a(0) = 0.3 au. Around half of the inner planet-forming disks have minimum solid masses of greater than or similar to 40 M-circle plus within 1 au. While transit observations do not tend to bias the median beta, they can lead to both significantly over- and underestimated Sigma(0)* and thus broaden the inferred distribution of disk masses. Nevertheless, detection biases cannot account for the full variance in the observed disk profiles; there is no universal MMEN if all planets formed in situ. The great diversity of solid disk profiles suggests that a substantial fraction (greater than or similar to 23%) of planetary systems experienced a history of migration.