Alpha Centauri

A Case Study of Interstellar Material Delivery: Alpha Centauri

By Keith Cowing

Press Release

February 6, 2025

Filed under Alpha Centauri, asteroids, Interstellar, meteorites, Oort Cloud, solar system

A Case Study of Interstellar Material Delivery: Alpha Centauri — α Cen’s orbit about the Galactic Centre viewed on the xy and yz planes (top row), as well as the orbits of the ejecta from α Cen viewed in a comoving frame (bottom row). Our Sun (Sol) is marked by a black hexagon and its orbital path indicated by a grey solid line (top row only). α Cen’s location and path are shown by a yellow star and blue solid line (top row only). In the bottom row, the comoving frame follows α Cen around its orbit while maintaining its orientation with the y-axis pointing towards the Galactic Centre (blue arrow) and α Cen’s velocity pointing in the -x direction (black arrow). This still frame is taken at t ≈ 3, 000 yr (that is, +3,000 years from the current epoch) after ∼ 100 Myr of integration. The colours of the ejecta represent the 3rd dimension of position, except that any particle that will at any point come within 100, 000 au of Sol are plotted in red. The full animation is available in the HTML version of this publication which shows the time evolution from t ≈ −100 Myr to t ≈ 10 Myr. The duration of the animation is 11 s. https://youtu.be/YABoYgNKr-I — astro-ph.EP

Interstellar material has been discovered in our Solar System, yet its origins and details of its transport are unknown. Here we present α Centauri as a case study of the delivery of interstellar material to our Solar System.

α Centauri is a mature triple star system that likely harbours planets and is moving towards us with the point of closest approach approximately 28,000 years in the future. Assuming a current ejection model for the system, we find that such material can reach our Solar System and may currently be present here. The material that does reach us is mostly a product of low (<2 km/s) ejection velocities, and the rate at which it enters our Solar System is expected to peak around the time of α Centauri ‘s closest approach.

If α Centauri ejects material at a rate comparable to our own Solar System, we estimate the current number of α Centauri particles larger than 100 m in diameter within our Oort Cloud to be 10⁶, and during α Centauri ‘s closest approach, this will increase by an order of magnitude. However, the observable fraction of such objects remains low as there is only a probability of 10⁻⁶ that one of them is within 10 au of the Sun.

A small number (∼10) meteors greater than 100 micrometers from α Centauri may currently be entering Earth’s atmosphere every year: this number is very sensitive to the assumed ejected mass distribution, but the flux is expected to increase as α Centauri approaches.

Cole R. Gregg, Paul A. Wiegert

Comments: Accepted for publication in PSJ (Jan 31, 2025). 15 pages, 2 tables, 9 figures (3 animations – https://www.youtube.com/playlist?list=PL8bn7jytqoQZkbnryQRmKWargaY0uKyrX )
Subjects: Earth and Planetary Astrophysics (astro-ph.EP); Astrophysics of Galaxies (astro-ph.GA); Solar and Stellar Astrophysics (astro-ph.SR)
Cite as: arXiv:2502.03224 [astro-ph.EP] (or arXiv:2502.03224v1 [astro-ph.EP] for this version)
https://doi.org/10.48550/arXiv.2502.03224
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Submission history
From: Cole Gregg
[v1] Wed, 5 Feb 2025 14:41:44 UTC (29,939 KB)
https://arxiv.org/abs/2502.03224
Astrobiology,

Keith Cowing

Explorers Club Fellow, ex-NASA Space Station Payload manager/space biologist, Away Teams, Journalist, Lapsed climber, Synaesthete, Na’Vi-Jedi-Freman-Buddhist-mix, ASL, Devon Island and Everest Base Camp veteran, (he/him) 🖖🏻

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