 Comet Metcalf–Brewington imaged by theZwicky Transient Facility on 10 November 2021 | |
| Discovery[1][2] | |
|---|---|
| Discovered by | Joel H. Metcalf Howard J. Brewington |
| Discovery site | Taunton, Massachusetts Cloudcroft, New Mexico |
| Discovery date | 10 October 1906 7 January 1991 |
| Designations | |
| P/1906 V2, P/1991 A1 | |
| |
| Orbital characteristics[4][5] | |
| Epoch | 31 March 2024 (JD 2460400.5) |
| Observation arc | 115.20 years |
| Number of observations | 607 |
| Aphelion | 6.960 AU |
| Perihelion | 2.572 AU |
| Semi-major axis | 4.766 AU |
| Eccentricity | 0.4593 |
| Orbital period | 10.406 years |
| Inclination | 17.949° |
| 184.08° | |
| Argument of periapsis | 230.10° |
| Mean anomaly | 73.309° |
| Last perihelion | 15 February 2022 |
| Next perihelion | 19 July 2032[3] |
| TJupiter | 2.710 |
| EarthMOID | 1.656 AU |
| JupiterMOID | 0.109 AU |
| Physical characteristics[4] | |
| Dimensions | 3.4 km (2.1 mi) |
| Comet total magnitude (M1) | 13.7 |
97P/Metcalf–Brewington is a periodicJupiter-family comet originally discovered byJoel H. Metcalf in 1906 but subsequentlylost.[6] A new observation in 1991 byHoward J. Brewington was matched to the 1906 sighting; the orbit was computed and the comet was observed again on its returns to perihelion in 2001, 2011, and 2022.[6]
On photographic plates taken on 15 November 1906,Joel H. Metcalf discovered the comet as a 12th-magnitude object within the constellationEridanus.[a]
The comet passed about 0.86 AU (129 million km) fromJupiter on September 1911, perturbing its orbit enough for astronomers to revise their calculations for the 1914 and 1922 apparitions.[7]Henrietta Swan Leavitt reported that she may have recovered Metcalf's comet in 1915, however the two images she took were later confirmed to be that of393 Lampetia instead.[8] The comet was never found after its last reported observation on 16 January 1907 and after a series of orbital calculations showed that viewing conditions were unfavorable on each subsequent apparition until 1975,[2] it was declared lost after 1922.[7]
Until 1975, Metcalf's comet was expected to appear no brighter than magnitude 18, although no attempts were made to find the comet due to unfavorable conditions.[9] In 7 January 1991,Howard J. Brewington discovered a new comet within the constellationCetus,[b] which was verified byAlan Hale in the same night.[10] Following additional observations byKatsuhito Ohtsuka andRobert H. McNaught between 7 and 9 January 1991,Brian G. Marsden noted that the orbit of Brewington's comet strongly resembled that of Metcalf's comet in 1906, concluding that they are one and the same object.[11] It is later determined that the previous calculations for the 1914 and 1922 apparitions were off by a few days and a couple months respectively, which caused the failure of this comet's recovery during those apparitions.[7]
Analysis of its light-curve revealed that during its 1991 apparition, comet Metcalf–Brewington had experienced a massive outburst that had brightened the comet by 11 magnitudes, or a factor of 25,000.[12] It was later determined that it might have been caused by thermal stresses on an exposed ice pocket rich inhydrogen cyanide (HCN) gas, which cracked the crust of its nucleus during perihelion.[12]
Shortly after being recovered, revised orbital calculations for the comet has revealed that it made a close encounter withJupiter at a distance of 0.11 AU (16 million km) in March 1993, where it was also predicted to return by 2000 or 2001.[13]
In October 2021, the comet experienced an outburst that expelled material out to 19,400 km (12,100 mi) from its nucleus, resulting in a temporary rise in apparent magnitude from 18 to 16.[14]
| Numbered comets | ||
|---|---|---|
| Previous 96P/Machholz | 97P/Metcalf–Brewington | Next 98P/Takamizawa |
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