Periodic Reporting for period 2 - PLANETESYS (The next-generation planet formation model)
Reporting period: 2019-01-01 to 2020-07-31
An important goal of the PLANETESYS project is the development of the PLANETESYS code to simulate the growth from dust grains to planetary systems. The framework for the code is now in place and has been tested on a supercomputer in Lund. The first results on the growth from dust to pebbles were published in 2020 (Eriksson et al., 2020, in print). We have also developed an algorithm for the formation of planetesimals and the dynamics of planetesimals - this paper is submitted to Astronomy & Astrophysics (Lorek & Johansen, 2020, submitted).
Meteorites are fragments of asteroids and they contain abundant chondrules of millimeter sizes. Those chondrules could be the pebbles from the solar protoplanetary disc, but the chondrules appear to have been melted and recrystallised as solid spherules. We have developed a new model where chondrules are melted by the heat from lightning in protoplanetary discs (Johansen & Okuzumi, 2018). This was a major milestone for PLANETESYS and the results have been presented at several interdisciplinary meetings on meteorites and planet formation.
Regarding dust growth and planetesimal formation, we have developed a novel model for converting the dust aggregate pebbles in protoplanetary discs into solid chondrules found in meteorites. Together with Satoshi Okuzumi the PI demonstrated how pebbles will melt because of lightning in protoplanetary discs. We are also progressing the formation of planetesimal formation by the streaming instability, demonstrating that the streaming instability can for planetesimals even when there is background turbulence present in the protoplanetary disc. The streaming instability model for planetesimal formation recently gained strong support from the analysis of the Kuiper belt object Arrokoth by the New Horizons mission. The New Horizons team concluded in three papers published in Science in 2020 that the properties of Arrokoth are consistent with formation by the streaming instability. This was a major science news story and the PI of PLANETESYS was interviewed by several media, including BBC and Washington Post.