308P/Lagerkvist–Carsenty
Periodic comet
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Comet Lagerkvist–Carsenty is a distant Jupiter-family comet with a 17-year orbit around the Sun. It was co-discovered by two European astronomers, Claes-Ingvar Lagerkvist[a] and Uri Carsenty.
Uri Carsenty
- P/1997 T3, P/2014 O2
- P/2014 QD604
 Comet Lagerkvist–Carsenty imaged from ESO on 24 November 1997 | |
| Discovery[1] | |
|---|---|
| Discovered by | Claes-Ingvar Lagerkvist Uri Carsenty |
| Discovery site | European Southern Observatory |
| Discovery date | 5 October 1997 |
| Designations | |
| |
| PJ97T030 | |
| Orbital characteristics[2][3] | |
| Epoch | 21 January 2022 (JD 2459600.5) |
| Observation arc | 18.50 years |
| Earliest precovery date | 1 October 1997 |
| Number of observations | 375 |
| Aphelion | 9.005 AU |
| Perihelion | 4.199 AU |
| Semi-major axis | 6.602 AU |
| Eccentricity | 0.36397 |
| Orbital period | 16.963 years |
| Inclination | 4.852° |
| 63.063° | |
| Argument of periapsis | 333.60° |
| Mean anomaly | 142.35° |
| Last perihelion | 7 May 2015 |
| Next perihelion | 1 May 2032 |
| TJupiter | 2.883 |
| Earth MOID | 3.263 AU |
| Jupiter MOID | 0.293 AU |
| Comet total magnitude (M1) | 10.7 |
| Comet nuclear magnitude (M2) | 13.5 |
Observational history
The comet was discovered as an asteroid-like object from photographic plates taken during a joint astronomical survey between the Uppsala Astronomical Observatory and the European Southern Observatory on the night of 5 October 1997.[1] At the time, the comet formerly known as P/1997 T3, was a 19th-magnitude object within the constellation Pisces.[b] It was initially thought to be a Jupiter trojan with no apparent activity,[4] until further orbital calculations had shown it was not gravitationally bound to Jupiter itself, but in a centaur-like orbit as far away as Saturn's distance to the Sun.[5][6]
On 29 July 2014, Erwin Schwab and his colleagues at the Tenerife Observatory later recovered the comet on its second apparition as P/2014 O2, where like its 1997 apparition, it exhibited very little cometary activity.[7]
Orbit
Lagerkvist–Carsenty is currently in a heliocentric orbit whose perihelion is at a distance of 4.2 AU (630 million km) and aphelion of 9.01 AU (1.348 billion km) from the Sun.[3] It completes one revolution roughly every 17 years, placed between the orbits of Jupiter and Saturn.
Orbital reconstructions in 2000 by the discoverers themselves had revealed that the comet made a close encounter with Saturn on 12 October 1954,[8] where it approached the giant planet at a distance of 0.0104 AU (1.56 million km).[2] The encounter had turned the orbit of the former centaur into that of a Jupiter-family comet in the present day.[9] The comet will make two close encounters with Jupiter by 2085 and 2188, respectively.[2]
Naming
The comet initially did not have a formal name since it was thought to be an asteroid upon discovery. However, by January 1998, the International Astronomical Union (IAU) had decided to rename P/1997 T3 as Lagerkvist–Carsenty, after the two discoverers who recognized its cometary nature before its discovery was announced.[10][c]
The comet received its official numerical designation, 308P, in January 2017.[11]
See also
- 450P/LONEOS, another former centaur that became a short-period comet after a close encounter with Saturn