 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 just experienced a massive outburst that brightened up the comet by 11 magnitudes![12] It was later determined that it might be 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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