A study published in the Icarus journal, led by predoctoral researcher Eloy Peña-Asensio of the Institute of Space Sciences (ICE-CSIC) and the Autonomous University of Barcelona (UAB), suggests that the FH1 meteor detected in 2022 by several satellite stations of the Finnish Fireball Network (FFN) could be a small rock that reached Earth from the Oort Cloud. This is the outermost region of the solar system, traditionally considered as a source of comets. The trajectory of FH1 would have been altered by the gravitational impulse induced by the Scholz binary star when it passed through the Oort Cloud.
This high-speed grazing meteor streaked across the sky over Finland for 5 seconds on 23 October 2022, ending its trajectory in the Gulf of Bothnia. It has been studied by the Meteorites, Minor Bodies and Planetary Sciences Group of the Institute of Space Sciences (ICE-CSIC) lead by Prof. Josep M. Trigo-Rodríguez, which coordinates the Spanish Fireball and Meteorite Recovery Network (SPMN-CSIC).
FH1 3D reconstruction. Credits: Eloy Peña-Asensio et al.
This meteoric event, practically as luminous as the planet Venus, became a clue to delve into the possible origin of the last projectiles registered in hyperbolic orbits. However, the scientific community has not yet reached a consensus regarding the existence of these high-energy impacts, which could theoretically have an interstellar origin.
Researchers Eloy Peña-Asensio (ICE-CSIC, UAB), Josep M. Trigo-Rodríguez (ICE-CSIC, IEEC) and Albert Rimola (UAB), in collaboration with other institutions, determined that the trajectory of the object is compatible with a gravitational impulse produced by the close transit of the Scholz binary star. This transit, which took place around 80,000 years ago, would have altered the small bodies furthest from the Sun. The possible "local" origin of FH1 could change our understanding of the Oort Cloud, since its properties point to host rocks with an asteroidal composition.
The study also examined other meteoric events catalogued by the Center for Near-Earth Object Studies (CNEOS). The authors previously discovered several fireballs with hyperbolic orbits, but they had a distribution of orbital inclinations that was excessively low to be a population of interstellar origin that arrived arbitrarily. Among them, the superbolide IM2, observed on 9 March 2017, could also be compatible with the close encounter of the Scholz system.
The discovery of the FH1 meteoroid could have significant implications for the evolution models of our planetary system, such as the dynamical instability scenario associated with Jupiter, which would have spread rocky material to the edge of the solar system.
The results of this study reinforce the idea that nearby stars or other massive objects could be a source of hyperbolic projectiles for Earth. This is the reason why the researchers point out that future impacts against Earth with hyperbolic orbits will have to be examined in detail before attributing an interstellar origin to them.