450P/LONEOS, also known by its formal designations P/2004 A1 and P/2022 Q3, is a distant periodic comet with a 22-year orbit around the Sun. It is one of several comets discovered by the Lowell Observatory Near-Earth-Object Search (LONEOS) program.
Observational history Discovery The comet was discovered as an 18th-magnitude object on CCD images taken by Brian A. Skiff as part of the Lowell Observatory's LONEOS program. The LONEOS images show the object with a stellar-like appearance, but its motion prompted Skiff to request additional observations. H. R. Miller (Perkins Observatory) and J. Young (Table Mountain Observatory) later found a coma about 4 arcseconds in diameter and a very faint tail about 10 arcseconds in length, confirming its cometary nature. At the time its cometary activity was detected, 450P/LONEOS (then known as P/2004 A1) was about from the Sun. The first orbital calculations were later published on the Minor Planet Center's website on 13 January 2004, alongside precovery images taken by the Kitt Peak Observatory dating as far back as 18 December 2003.
Follow-up observations The comet was successfully recovered from observations taken by the Gemini North Observatory in August 2022, where it was noted to be 4.5 magnitudes fainter than previously predicted. The comet received its official numerical designation (450P) alongside 8 other comets on February 2023.
Orbit , 450P/LONEOS has a heliocentric orbit inclined about 10.65 degrees from the ecliptic. Its perihelion distance is about while its aphelion goes as far back as from the Sun. Orbital calculations indicated that it made a close encounter with Saturn in 1992, when it came within to the giant planet. This resulted in its semimajor axis to be significantly decreased by . A long-term orbital investigation indicated that this is likely its first sojourn to the inner Solar System as it transitions from a centaur into a Jupiter-family comet.
On 11 July 2026, the comet approached Jupiter at a distance of , further sending it into a closer orbit around the Sun.
Physical characteristics A 2011 study revealed that based on its measured dust activity, the nucleus of 450P/LONEOS may be somewhere between and in radius. At the time it was in an inactive state between 2019 and 2024, further observations from both the Gemini Observatory and the James Webb Space Telescope (JWST) revised this to roughly . Its asymmetrical coma and anti-tail during its 2004 apparition extended up to a distance of in the solar direction.
During its 2022 apparition, it has a low dust production rate of about ~4.8 kg/sec−1 primarily driven by outgassing from amorphous water ice crystallization at temperatures between 140–160 K.
See also 308P/Lagerkvist–Carsenty, another former centaur that became a short-period comet after a close encounter with Saturn
Notes
References
External links
at the Minor Planet Center database 450P/LONEOS at Seiichi Yoshida's website 450P/LONEOS at Gideon van Buitenen's website