77P/Longmore
{{short description|Periodic comet}}
{{Infobox comet
| name = 77P/Longmore
| image = 77P 2023-04-27 image ZTF-sso-226-zr-fov-13arcmin.png
| caption = Longmore's Comet imaged from the Zwicky Transient Facility on 27 April 2023
| discoverer = Andrew J. Longmore
| discovery_site = Siding Spring Observatory
| discovery_date = 10 June 1975
| mpc_name = P/1975 L1, P/1981 A1
| designations = {{unbulleted|1974 XIV, 1981 XVI|1988 XVIII|1975g, 1981a, 1987c1|1994q}}
| orbit_ref = {{r|jpldata|MPC}}
| epoch = 17 October 2024 (JD 2460600.5)
| observation_arc = 49.37 years
| obs = 2,712
| perihelion = 2.348 AU
| aphelion = 4.895 AU
| semimajor = 3.621 AU
| period = 6.891 years
| eccentricity = 0.35166
| inclination = 24.320°
| asc_node = 14.457°
| arg_peri = 196.65°
| mean = 80.540°
| tjup = 2.860
| Earth_moid = 1.338 AU
| Jupiter_moid = 0.202 AU
| physical_ref = {{r|Paradowski_2022}}
| mean_radius = {{val|1.66|0.12}} km
| density = {{val|550|80}} kg/m3
| M1 = 9.2
| M2 = 13.3
| magnitude =
| last_p = 3 April 2023
| next_p = 18 February 2030{{r|Yoshida}}
}}
77P/Longmore is a periodic comet in the Solar System, with a period of 6.8 years. It is the only comet discovered by Australian astronomer, Andrew Jonathan Longmore.
Observational history
It was discovered by Andrew Jonathan Longmore on a photographic plate taken on 10 June 1975 at the 1.22m Schmidt telescope at Siding Spring Observatory, New South Wales, Australia. Its brightness was estimated at an apparent magnitude of 17. After further observations Brian G. Marsden was able to calculate the perihelion date at 4 November 1975 and the orbital period as 6.98 years.{{r|cometography}}
The next perihelion date was computed to be 21 October 1981. T. Seki of Geisei, Japan relocated the comet on 2 January 1981 with a brightness of magnitude 18. It has since been observed in 1988, 1995, 2002 and 2009.
On 17 October 1963, the comet had passed {{convert|0.1577|AU|e6km e6mi|abbr=unit}} from Jupiter.{{r|jpldata}}
During the 2023 perihelion passage the comet brightened to about apparent magnitude 14–15.{{r|MPC}}
References
{{Reflist|refs=
| author1= G. W. Kronk
| title= 77P/Longmore
| url= https://cometography.com/pcomets/077p.html
| website= Cometography.com
| access-date= 25 February 2015 }}
| title= 77P/Longmore – JPL Small-Body Database Lookup
| url= https://ssd.jpl.nasa.gov/tools/sbdb_lookup.html#/?sstr=77P
| website= ssd.jpl.nasa.gov
| publisher= Jet Propulsion Laboratory
| access-date= 28 July 2012 }}
| title= 77P/Longmore Orbit
| url= http://www.minorplanetcenter.net/db_search/show_object?object_id=77P
| publisher= Minor Planet Center
| access-date= 7 April 2017 }}
| author1= M. L. Paradowski
| title= A New Indirect Method of Determining Density of Cometary Nuclei
| url= https://acta.astrouw.edu.pl/Vol72/n2/pdf/pap_72_2_4.pdf
| journal= Acta Astronomica
| year= 2022
| volume= 72
| issue= 2
| pages= 141–159
| bibcode= 2022AcA....72..141P
| issn= 0001-5237
| doi= 10.32023/0001-5237/72.2.4
| doi-access= free }}
| author1= S. Yoshida
| title= 77P/Longmore
| url= http://www.aerith.net/comet/catalog/0077P/index.html
| website= www.aerith.net
| date= 6 March 2011
| access-date= 18 February 2012 }}
}}
External links
- {{JPL Small Body|id=1000059}}
- [http://cometography.com/pcomets/077p.html 77P/Longmore] at Gary W. Kronk's Cometography
{{PeriodicComets Navigator|76P/West–Kohoutek–Ikemura|78P/Gehrels}}
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{{Authority control}}
{{DEFAULTSORT:Longmore, 077P}}
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