Roberto Gorelli points our attention at a recently published meteor related paper.
Realistic gravitational focusing of meteoroid streams
This paper has been submitted for publication to Monthly Notices of the Royal Astronomical Society by Althea V. Moorhead, Tiffany D. Clements, and Denis Vida.
Abstract: The number density and flux of a meteoroid stream is enhanced near a massive body due to the phenomenon known as gravitational focusing. The greatest enhancement occurs directly opposite the massive body from the stream radiant: as an observer approaches this location, the degree of focusing is unbound for a perfectly collimated stream. However, real meteoroid streams exhibit some dispersion in radiant and speed that will act to eliminate this singularity. In this paper, we derive an analytic approximation for this smoothing that can be used in meteoroid environment models and is based on real measurements of meteor shower radiant dispersion.
You can download this paper for free: https://arxiv.org/pdf/2003.05458.pdf (14 pages).