100P/Hartley
{{Short description|Periodic comet}}
{{About|100P/Hartley|other comets|Comet Hartley (disambiguation){{!}}Comet Hartley}}
{{Use dmy dates|date=May 2025}}
{{Infobox comet
| name = 100P/Hartley
| image =
| discovery_ref = {{r|IAUC_4077}}
| discoverer = Malcolm Hartley
| discovery_site = UK Schmidt Telescope
| discovery_date = 13 June 1985
| mpc_name = P/1985 L1
P/1991 E1
| designations = {{unbulleted|Hartley 1|1991 VII, 1985 VII|1985f, 1991j}}
| orbit_ref = {{r|jpldata|MPC}}
| epoch = 13 September 2023 (JD 2460200.5)
| observation_arc = 37.17 years
| obs = 658
| perihelion = 2.018 AU
| aphelion = 4.844 AU
| semimajor = 3.416 AU
| eccentricity = 0.41183
| period = 6.354 years
| inclination = 25.567°
| asc_node = 37.687°
| arg_peri = 181.96°
| mean = 67.750°
| tjup = 2.851
| Earth_moid = 1.003 AU
| Jupiter_moid = 0.133 AU
| physical_ref = {{r|jpldata|Lamy_2004}}
| mean_radius = < {{cvt|1.2|km|mi}}
| M1 = 10.0
| M2 = 16.2
| last_p = 10 August 2022
| next_p = 15 December 2028{{r|Horizons2028}}
}}
100P/Hartley, also known as Hartley 1, is a periodic, Jupiter family comet in the Solar System.
On 29 April 2164, the comet will pass {{convert|0.487|AU|e6km e6mi|abbr=unit}} from Earth.{{r|jpldata}}
Observational history
= Discovery =
Malcolm Hartley discovered the comet from CCD images taken from the UK Schmidt Telescope in Australia on 13 June 1985.{{r|IAUC_4077}} At the time, the comet was a 16th-magnitude object within the constellation Virgo,{{efn|Reported initial position upon discovery was: α {{=}} {{RA|11|48}}, δ {{=}} {{DEC|4|21}}{{sfn|Kronk|Meyer|Seargent|2017|pp=149–150}}}} with a prominent tail extending about 1 arcminute towards the southeast. Despite the discovery announcement, Hartley remained the comet's only observer for the next three weeks.{{sfn|Kronk|Meyer|Seargent|2017|pp=149–150}}
= Follow-up observations =
An additional observation by Hartley on 10 July 1985 has allowed Brian G. Marsden to compute the elliptical orbit of the comet for the first time, revealing that it was a short-period comet with a 5.66-year orbit around the Sun.{{r|IAUC_4084}} James B. Gibson obtained the only known Northern hemisphere observations of the comet during its first apparition on 27–29 July 1985.{{sfn|Kronk|Meyer|Seargent|2017|pp=149–150}} It was last detected by Alan C. Gilmore on 14 August 1985.{{sfn|Kronk|Meyer|Seargent|2017|pp=149–150}}
The small number of observations during its 1985 apparition has caused uncertainties in revising its orbit that it was almost considered lost.{{r|cometography}} It was successfully recovered by David H. Levy, Carolyn and Eugene Shoemaker on the night of 12 March 1991,{{sfn|Kronk|Meyer|Seargent|2017|pp=574–575}} about 16 degrees from its predicted position.{{r|IAUC_5209}} Marsden later noted that the comet made a close encounter with Jupiter on February 1988, passing within {{convert|0.36|AU|e6km|abbr=unit}} from the giant planet.{{r|IAUC_5209}}
References
= Notes =
{{Notelist}}
= Citations =
{{reflist|refs=
| author1= G. W. Kronk
| title= 100P/Hartley 1
| url= https://cometography.com/pcomets/100p.html
| website= Cometography.com
| access-date= 22 May 2025 }}
| title= Horizons Batch for 100P/Hartley 1 on 2028-Dec-15
| publisher= JPL Horizons
| type= Perihelion occurs when rdot flips from negative to positive
| url= https://ssd.jpl.nasa.gov/horizons_batch.cgi?batch=1&COMMAND=%27100P%27&START_TIME=%272028-Dec-15%27&STOP_TIME=%272028-Dec-17%27&STEP_SIZE=%273%20hours%27&QUANTITIES=%2719%27
| access-date= 29 April 2023 }} (JPL#38/Soln.date: 20 August 2022)
| author1= M. Hartley
| editor1= B. G. Marsden
| title= Comet Hartley (1985f)
| url= http://www.cbat.eps.harvard.edu/iauc/04000/04077.html
| journal= IAU Circular
| date= 20 June 1985
| volume= 4077
| issue= 1
| bibcode= 1985IAUC.4077....1H }}
| author1= M. Hartley
| editor1= B. G. Marsden
| title= Periodic Comet Hartley (1985f)
| url= http://www.cbat.eps.harvard.edu/iauc/04000/04084.html
| journal= IAU Circular
| date= 18 July 1985
| volume= 4084
| issue= 1
| bibcode= 1985IAUC.4084....1H }}
| author1= C. S. Shoemaker
| author2= E. M. Shoemaker
| author3= D. H. Levy
| author4= B. Dintinjana
| author5= H. Mikuz
| author6= R. H. McNaught
| author7= B. G. Marsden
| display-authors= 3
| editor1= D. W. Green
| title= Periodic Comet Hartley (1991j)
| url= http://www.cbat.eps.harvard.edu/iauc/05200/05209.html
| journal= IAU Circular
| date= 16 March 1991
| volume= 5209
| issue= 1
| bibcode= 1991IAUC.5209....1S }}
| title= 100P/Hartley 1 – JPL Small-Body Database Lookup
| url= https://ssd.jpl.nasa.gov/tools/sbdb_lookup.html#/?sstr=100P
| website= ssd.jpl.nasa.gov
| publisher= Jet Propulsion Laboratory
| access-date= 22 May 2025 }}
| author1= P. L. Lamy
| author2= I. Toth
| author3= Y. R. Fernández
| author4= H. A. Weaver
| title= Comets II
| chapter= The Sizes, Shapes, Albedos, and Colors of Cometary Nuclei
| chapter-url= https://physics.ucf.edu/~yfernandez/papers/comets2chapter/comets2reprint.pdf
| year= 2004
| pages= 223–264
| jstor= j.ctv1v7zdq5.22 }}
| title= 100P/Hartley Orbit
| url= http://www.minorplanetcenter.net/db_search/show_object?object_id=100P
| publisher= Minor Planet Center
| access-date= 1 November 2014 }}
}}
= Bibliography =
- {{Cite book
| last1=Kronk | first1=Gary W.
| last2=Meyer | first2= Maik
| last3=Seargent | first3= David A. J.
| date=2017
| title=Cometography: A Catalog of Comets
| volume= 6: 1983–1993
| publisher= Cambridge University Press
| isbn= 978-0-521-87216-4
}}
External links
- [http://www.aerith.net/comet/catalog/0100P/index.html 100P/Hartley] at Seiichi Yoshida's website
- {{JPL small body|id=1000040}}
{{PeriodicComets Navigator|99P/Kowal|101P/Chernykh}}
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{{Authority control}}
{{DEFAULTSORT:Hartley, 100P}}