Identification of a Minimoon Fireball

Abstract

Objects gravitationally captured by the Earth-Moon system are commonly called temporarily captured orbiters (TCOs), natural Earth satellites, or minimoons. TCOs are a crucially important subpopulation of near-Earth objects to understand because they are the easiest targets for future sample-return, redirection, or asteroid mining missions. Only one TCO has ever been observed telescopically, 2006 RH 120 , and it orbited the Earth for about 11 months [Kwiatkowski et al., 2009]. Additionally, only one TCO fireball has ever been observed prior to this study [Clark et al., 2016]. We present our observations of an extremely slow fireball (codename DN160822_03) with an initial velocity of around 11.0 km s −1 that was detected by 6 of the high-resolution digital fireball observatories located in the South Australian region of the Desert Fireball Network (DFN). Due to the inherent dynamics of the system, the probability of the meteoroid being temporarily captured before impact is extremely sensitive to its' initial velocity. We examine the sensitivity of the fireball's orbital history to the chosen triangulation method. We use the numerical integrator REBOUND to assess particle histories and assess the statistical origin of DN160822_03. From our integrations we have found that the most probable capture time, velocity, semi-major axis, NEO group, and capture mechanism vary annually for this event. Most particles show that there is an increased capture probability during Earth's aphelion and perihelion. In the future, events like these may be detected ahead of time using telescopes like the LSST, and the pre-atmospheric trajectory can be verified.

Trajectory, recovery, and orbital history of the Madura Cave meteorite

“…To better understand the dynamical history of the object in near-Earth space, we create 1000 clones of the initial observed vector within the formal uncertainties, and backtrack their positions in the past. This is done following similar methods as Shober et al (2019Shober et al ( , 2020: the Rebound package is used in simulations where the meteoroid clones evolve under the influence of the eight planets, the Moon, and the Sun. The simulation is run using the IAS15 adaptive timestep integrator, and the state vector of each particle in the system is recorded every 10,000 yr (Rein & Spiegel, 2015).…”

“…This is done following similar methods as Shober et al. (2019, 2020): the Rebound package is used in simulations where the meteoroid clones evolve under the influence of the eight planets, the Moon, and the Sun. The simulation is run using the IAS15 adaptive timestep integrator, and the state vector of each particle in the system is recorded every 10,000 yr (Rein & Spiegel, 2015).…”

Where Did They Come From, Where Did They Go: Grazing Fireballs

“…) with coverage area expected to increase to 2% of the Earth's entire surface. This coverage area makes the GFO particularly well suited to characterize grazing meteoroids and other more rare fireball events [Shober et al, 2019].…”

Statistical analysis of fireballs: Seismic signature survey

“…We also looked for seismic signals from fireballs that had dropped a meteorite (Murrili, Sansom et al (2020); Dingle Dell, Devillepoix et al (2018); DN160822_03, Shober et al (2019)) that were recovered from the field. The closest stations to these events were 150; 93 and 169; and 191 km respectively and show noisy seismic data and no signals.…”