PDS 70, located 367 light-years away in the constellation Centaurus, is a unique system that features fully formed planets within a still-forming protoplanetary disk.

Recent observations from the Atacama Large Millimeter/submillimeter Array (ALMA) have confirmed that planets forming in protoplanetary disks, such as that around PDS 70, can trigger the formation of additional planets.

An international team led by Kiyoaki Doi from the Max Planck Institute for Astronomy conducted high-resolution observations at longer wavelengths to investigate the PDS 70 protoplanetary disk.

Using high-resolution 3 mm observations, ALMA mapped the dust grain distribution, revealing a concentrated accumulation of dust outside the orbits of the known planets.

ALMA's longer wavelength observations provide enhanced clarity on dust distribution, highlighting the importance of using multiple wavelengths for a comprehensive understanding of planetary systems.

The gravitational interactions of the two known planets in the PDS 70 system are likely causing dust grains to accumulate, which may lead to the formation of a new planet.

These clumped dust grains are hypothesized to coalesce and form new planets, supporting the theory of sequential planetary formation akin to falling dominos.

This sequential planet formation process could explain the development of multi-planet systems, similar to our Solar System.

The findings enhance our understanding of planetary system formation and the role of existing planets in triggering the growth of new planets.

Astronomers have identified over 5,500 planetary systems, with more than 1,000 confirmed to contain multiple planets, although the exact mechanisms behind the formation of multi-planet systems remain largely unknown.

The latest ALMA findings suggest that existing planets influence the surrounding material, concentrating dust into a narrow region, which could lead to the formation of additional planets.

The research is detailed in the paper 'Asymmetric Dust Accumulation of the PDS 70 Disk Revealed by ALMA Band 3 Observations', published on October 14, 2024, in The Astrophysical Journal Letters.