Gravitational focusing

The concept of gravitational focusing describes how the gravitational attraction between two particles increases the probability that they will collide. Without gravitational force, the likelihood of a collision would depend on the cross-sectional area of the two particles. However, the presence of gravity can cause particles that would have otherwise missed each other to be drawn together, effectively increasing the size of their cross-sectional area.^[1]

Function

Gravitational focusing applies to extended objects like the Moon, planets and the Sun, whose interior density distributions are well known.^[2] Gravitational focusing is responsible for the power-law mass function of star clusters.^[3] Gravitational focusing plays a significant role in the formation of planets, as it shortens the time required for them to form and promotes the growth of larger particles.^[1]

Dark matter

Gravitational focusing typically only has a small impact on the relaxed halo dark matter component, with effects typically remaining at around the 5% level. However, the impact of gravitational focusing on dark matter substructures could potentially be much greater.^[4]

References

^ ^a ^b Barnes, Rory (2011), "Gravitational Focusing", in Gargaud, Muriel; Amils, Ricardo; Quintanilla, José Cernicharo; Cleaves, Henderson James (Jim) (eds.), Encyclopedia of Astrobiology, Berlin, Heidelberg: Springer, p. 692, doi:10.1007/978-3-642-11274-4_670, ISBN 978-3-642-11274-4, retrieved 2023-01-01
^ Sofue, Yoshiaki (June 2020). "Gravitational Focusing of Low-Velocity Dark Matter on the Earth's Surface". Galaxies. 8 (2): 42. arXiv:2005.08252. doi:10.3390/galaxies8020042. ISSN 2075-4434.
^ Kuznetsova, Aleksandra; Hartmann, Lee; Burkert, Andreas (2017-02-21). "Gravitational Focusing and the Star Cluster Initial Mass Function". The Astrophysical Journal. 836 (2): 190. arXiv:1702.00279. doi:10.3847/1538-4357/aa5d51. ISSN 1538-4357. S2CID 119484707.
^ Kim, Hyungjin; Lenoci, Alessandro (2022-03-31). "Gravitational focusing of wave dark matter". Physical Review D. 105 (6): 063032. arXiv:2112.05718. doi:10.1103/PhysRevD.105.063032. S2CID 245117706.

[:0-1] Barnes, Rory (2011), "Gravitational Focusing", in Gargaud, Muriel; Amils, Ricardo; Quintanilla, José Cernicharo; Cleaves, Henderson James (Jim) (eds.), Encyclopedia of Astrobiology, Berlin, Heidelberg: Springer, p. 692, doi:10.1007/978-3-642-11274-4_670, ISBN 978-3-642-11274-4, retrieved 2023-01-01

[2] Sofue, Yoshiaki (June 2020). "Gravitational Focusing of Low-Velocity Dark Matter on the Earth's Surface". Galaxies. 8 (2): 42. arXiv:2005.08252. doi:10.3390/galaxies8020042. ISSN 2075-4434.

[3] Kuznetsova, Aleksandra; Hartmann, Lee; Burkert, Andreas (2017-02-21). "Gravitational Focusing and the Star Cluster Initial Mass Function". The Astrophysical Journal. 836 (2): 190. arXiv:1702.00279. doi:10.3847/1538-4357/aa5d51. ISSN 1538-4357. S2CID 119484707.

[4] Kim, Hyungjin; Lenoci, Alessandro (2022-03-31). "Gravitational focusing of wave dark matter". Physical Review D. 105 (6): 063032. arXiv:2112.05718. doi:10.1103/PhysRevD.105.063032. S2CID 245117706.

[1]

[2]

[3]

[4]