A recently discovered asteroid designated 2024 PT5, a member of the Apollo asteroid group, is projected to become gravitationally tethered to Earth for nearly 2 months.
The asteroid was detected on August 7, 2024, and its capture is expected to start at 20:02 UTC on September 29.
The temporary mini-moon phase will last 56.6 days, and 2024 PT5 will resume its heliocentric orbit at 10:33 UTC on November 25, 2024. After completing its flyby, 2024 PT5 will leave Earth’s orbit until its next visit in 2055.
While this asteroid poses no threat to the planet, its momentary capture allows astronomers to examine this exciting phenomenon. It occurs sporadically when minor asteroids approach Earth and are lured into a short-lived orbit. This is consistent with observations of other asteroids, such as 1991 VG and 2022 NX1, which had horseshoe-shaped orbits around Earth.
Newly-discovered #asteroid 2024 PT5 is about to undergo a “mini-moon event” when its geocentric energy becomes negative from September 29 – November 25. pic.twitter.com/pVYAmSbkCF
— Tony Dunn (@tony873004) September 10, 2024
Although these mini-moon events are uncommon, they occur occasionally, with the most recent occurring in 2020.
For instance, 2006 RH120 was gravitationally bound to Earth from July 2006 to July 2007, completing multiple orbits before escaping. Similarly, 2020 CD3 remained in Earth’s orbit for several years before escaping in May 2020. In February 1992, 1991 VG was briefly captured by Earth’s gravity before resuming its heliocentric orbit. Another example, 2022 NX1, has been a short-lived mini-moon twice, in 1981 and 2022, and is expected to return in 2051.
2024 PT5 was discovered by a group of astronomers from the Jet Propulsion Laboratory (JPL) who are currently tracking its trajectory and behavior. The discovery was made as part of ongoing research into Near-Earth Objects (NEOs) to assess potential dangers and better understand their orbital dynamics. The international astronomical community is also active, providing observational data to help improve the asteroid’s orbit.
Simulations show that the asteroid’s orbit will be steady for several decades, with the subsequent close encounter with Earth projected around 2055. These events allow scientists to examine the mechanics of NEOs and how their orbits shift in response to Earth’s gravity.
Using simulations and models based on the DE440/441 planetary ephemeris, astronomers validated the asteroid’s brief capture and release and its ultimate return to our area decades later.
References:
¹ 2024 PT5 – MPC – Accessed September 15, 2024
² 2024 PT5 – JPL – Accessed September 15, 2024
³ A Two-month Mini-moon: 2024 PT5 Captured by Earth from September to November – Carlos de la Fuente Marcos and Raúl de la Fuente Marcos – 2024 Res. Notes AAS 8 224 – September 2024 – – OPEN ACCESS