This is an old revision of this page, as edited by C messier (talk | contribs) at 15:07, 2 January 2025 (←Created page with '{{short description|Periodic comet with 9 year orbit}} {{Infobox comet | name = 489P/Denning | image = | caption = | discovery_ref = <ref name="cometography">{{cite web |last1=Kronk |first1=Gary |title=D/1894 F1 (Denning) |url=https://cometography.com/pcomets/1894f1.html |website=cometography.com |access-date=2 January 2025}}</ref> | discoverer = William Frederick Denning | discovery_date = March 26, 1894 | designations...'). The present address (URL) is a permanent link to this revision, which may differ significantly from the current revision.
Revision as of 15:07, 2 January 2025 by C messier (talk | contribs) (←Created page with '{{short description|Periodic comet with 9 year orbit}} {{Infobox comet | name = 489P/Denning | image = | caption = | discovery_ref = <ref name="cometography">{{cite web |last1=Kronk |first1=Gary |title=D/1894 F1 (Denning) |url=https://cometography.com/pcomets/1894f1.html |website=cometography.com |access-date=2 January 2025}}</ref> | discoverer = William Frederick Denning | discovery_date = March 26, 1894 | designations...')(diff) ← Previous revision | Latest revision (diff) | Newer revision → (diff) Periodic comet with 9 year orbit| Discovery | |
|---|---|
| Discovered by | William Frederick Denning |
| Discovery date | March 26, 1894 |
| Designations | |
| Alternative designations | P/2007 HE4, D/1894 F1, 1894 I, 1894a |
| Orbital characteristics | |
| Epoch | 18 August 2002 |
| Aphelion | 7.312 AU |
| Perihelion | 1.575 AU |
| Semi-major axis | 4.443 AU |
| Eccentricity | 0.6456 |
| Orbital period | 9.37 years |
| Inclination | 4.007° |
| Last perihelion | 2 September 2016 |
| Next perihelion | 4 December 2025 |
| TJupiter | 2.579 |
| Earth MOID | 0.596 AU |
| Comet total magnitude (M1) | 7.6 |
489P/Denning is a Jupiter-family comet with an orbital period of 9.4 years. It was discovered by William Frederick Denning on 26 March 1894 but was subsequently lost until 2024, when asteroid 2007 HE4 was identified as the same object.
Observational history
William Frederick Denning was searching comets from Bristol, England, when on 26 March 1894 found a faint object in Leo Minor. The next few days the magnitude of the comet was reported to be about 11. The comet also featured a tail about 5 arcminutes long. The comet upon discovery had passed both the perihelion and perigee and was becoming fainter. In April the comet was discovered as very faint and elongated. Few observations were made in May. The comet was last detected on 5 June 1894. It is possible the comet experienced an outburst in 1894.
The first orbit was calculated by Lipót Schulhof with positions from 27 to 31 March and indicated a parabolic orbit with perihelion on 13 February 1894. However, by mid April he suspected that the comet deviated from the orbit. The first elliptical he calculated, with position from 27 March to 25 April, had a perihelion date on 9 February and an orbital period of 6.74 years. Other orbital calculated were 7.94 years by Lewis Boss, 6.79 years by Schulhof, 6.76 years by John Russell Hind, and 7.70 years by Hind.
The comet wasn't recovered and became lost. In 2024 it was noted that Mars-crossing asteroid 2007 HE4, which was discovered by LINEAR on 17 April 2007 with an apparent magnitude of 18.7–19.5, had a comet-like orbit. Maik Meyer found that the asteroid's orbit was a good match with the proposed orbit of comet Denning. Images of the object by the Great Shefford Observatory from 18 and 19 April were re-examined and it was found it appeared slightly elongated, with an aspect ratio of 3:2 when compared with nearby stars. Images obtained by the 1.82m telescope of the Dominion Astrophysical Observatory on 19 April 2007 when stacked showed a coma with a diameter of 5".3 and a faint, spike-like tail extending for 8 arcseconds. The apparitions from 1972 to 1997 weren't favorable. The 1963–4 apparition was favorable, however no plates were found.
References
- ^ Kronk, Gary. "D/1894 F1 (Denning)". cometography.com. Retrieved 2 January 2025.
- "Small-Body Database Lookup: 489P/Denning". ssd.jpl.nasa.gov. Retrieved 2 January 2025.
- ^ Green, Daniel (2 August 2024). "COMET P/2007 HE_4 = P/1894 F1 (DENNING)". Central Bureau for Astronomical Telegrams. 5425.
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