322P/SOHO
{{Short description|Kracht sungrazer comet}}
{{Use dmy dates|date=January 2020}}
{{Infobox comet
| name = 322P/SOHO
| image =
| caption =
| discovery_ref =
| discoverer = SOHO
{{smalldiv|{{bulleted|Terry Lovejoy|Kazimieras Černis|Bo Zhou|Sebastian F. Hönig}}}}
| discovery_date = 4 September 1999
| mpc_name = {{unbulleted|P/1999 R1|P/2003 R5|P/2007 R5|P/2011 R4}}
| designations = SOHO-85{{r|sungrazer}}
SOHO-661
| orbit_ref = {{r|jpldata|MPC}}
| epoch = 15 September 2015 (JD 2457280.5)
| observation_arc = 15.93 years
| earliest_precovery_date = 27 November 254?{{r|Kronk_1999}}
| obs = 319
| perihelion = 0.0507 AU
| aphelion = 4.979 AU
| semimajor = 2.516 AU
| max_speed = 187 km/s (2023){{r|Horizons2023}}
| min_speed = 1.9 km/s (2017)
| eccentricity = 0.97869
| period = 3.992 years
| inclination = 12.583°
| asc_node = 359.48°
| arg_peri = 49.098°
| mean = 2.700°
| tjup = 2.347
| Earth_moid = 0.092 AU
| Jupiter_moid = 1.044 AU
| physical_ref = {{r|esa|Knight_2016}}
| dimensions = ~{{cvt|150|–|320|m|ft}}
| rotation = {{val|2.8|0.3}} hours
| density = ~1.00 g/cm3
| spectral_type = (V–R) {{=}} {{val|0.41|0.04}}
(R–I) {{=}} {{val|0.24|0.09|}}
| albedo = 0.09–0.42
| M1 = 19.0
| M2 =
| last_p = 21 August 2023{{r|Horizons2023}}
| next_p =
}}
322P/SOHO is the first periodic comet to be discovered using the automated telescopes of the SOHO (SOlar and Heliospheric Observatory) spacecraft, and second to be given a numbered designation, after 321P/SOHO.{{r|second}} At perihelion, it is six times closer to the Sun than the planet Mercury.
Observational history
The comet was first spotted by Terry Lovejoy after analyzing SOHO imagery on 4 September 1999.
After Kazimieras Černis spotted another SOHO comet in 2003, Sebastian F. Hönig, later determined that both P/1999 R1 and P/2003 R5 might be the same object, where he predicted its return in 2007.{{r|Hönig_2006|Jaggard_2007}} His calculations were later proven correct when it was successfully recovered by Bo Zhou as P/2007 R5 after analyzing SOHO images on 10 September 2007. It became one of the first comets that SOHO has discovered that is confirmed to be periodic.
Bo Zhou recovered the comet once again on September 6, 2011.{{r|esa}} It was observed again in September 2019.[https://www.syfy.com/syfywire/the-case-of-the-sun-diving-asteroid-that-thinks-its-a-comet The case of the Sun-diving asteroid that thinks it's a comet] Phil Plait, September 4, 2019
= Possible connection with the Great Comet of 254 AD =
It has been suggested that 322P/SOHO is associated with a comet observed in November–December 254 AD and is mentioned in East Asian sources to have an extremely long tail.{{r|Kronk_1999|Cui_2025}} If the association is correct, it is possible that the comet split in 254 AD, resulting in intense cometary activity, but activity decreased afterwards as the comet lost most of its volatiles, and no longer displays a tail or a prominent coma. Current activity is fueled by sodium sublimation.{{r|Cui_2025}}
Physical characteristics
322P/SOHO is either an extinct comet or an active asteroid.{{r|Zhou_2011}} Light-curve and infrared observations by Spitzer in 2016 suggest that its nucleus is probably only {{cvt|150|–|320|m|ft}} in diameter, with a rotation period lasting {{val|2.8|0.3}} hours.{{r|Knight_2016}}
Orbit
| class=wikitable style="text-align:center; font-size:11px; float:right; margin:2px" | |
| bgcolor= style="font-size: smaller;"
| colspan="8" style="text-align:center;"|Perihelion distance | |
| Perihelion date | Perihelion (AU) |
|---|---|
| 1955-04-18 | 0.0651 |
| 1983-08-08 | 0.0597 |
| 1999-09-05 | 0.0563 |
| 2015-09-04 | 0.0535 |
| 2019-08-31 | 0.0506 |
| 2023-08-21 | 0.0501 |
| 2027-08-11 | 0.0505 |
| 2031-08-01 | 0.0479 |
| 2047-05-23 | 0.0451 |
322P/SOHO is a member of the Kracht sungrazer family of comets.{{r|sungrazer}} On April 11, 1947 it passed about {{convert|7.1|+/-|0.22|e6km|abbr=unit|sigfig=2}} from Earth.
Exploration
On 2 September 2019, NASA's Parker Solar Probe incidentally passed the tail of 322P/SOHO at a distance of {{convert|0.012|AU|e6km|abbr=unit}}, making direct measurements of the comet as it interacts with the solar wind.{{r|He_2021}}
See also
References
{{reflist|refs=
| author1= J. Cui
| author2= G. Li
| author3= Y. Zhao
| title= 322P/SOHO: The Counterpart of a Historical Comet in 254 CE?
| journal= Icarus
| year= 2025
| volume= 429
| pages= 116382
| bibcode= 2025Icar..42916382C
| doi= 10.1016/j.icarus.2024.116382 }}
| author1= J. He
| author2= B. Cui
| author3= L. Yang
| author4= C. Hou
| author5= L. Zhang
| author6= W. H. Ip
| author7= Y. D. Jia
| author8= C. Dong
| author9= D. Duan
| author10= Q. Zong
| author11= S. D. Bale
| author12= M. Pulupa
| author13= J. W. Bonnell
| author14= T. Dudok De Wit
| author15= K. Goetz
| author16= P. R. Harvey
| author17= R. J. MacDowall
| author18= D. M. Malaspina
| display-authors= 5
| title= The Encounter of the Parker Solar Probe and a Comet-like Object Near the Sun: Model Predictions and Measurements
| url= https://iopscience.iop.org/article/10.3847/1538-4357/abdf4a/pdf
| journal= The Astrophysical Journal
| year= 2021
| volume= 910
| issue= 1
| pages= 7–18
| bibcode= 2021ApJ...910....7H
| arxiv= 2012.00005
| doi= 10.3847/1538-4357/abdf4a
| doi-access= free }}
| author1= S. F. Hönig
| title= Identification of a new short-period comet near the sun
| url= https://www.aanda.org/articles/aa/pdf/2006/02/aa3991-05.pdf
| journal= Astronomy & Astrophysics
| year= 2006
| volume= 445
| issue= 2
| pages= 759–763
| bibcode= 2006A&A...445..759H
| arxiv= astro-ph/0509168
| doi= 10.1051/0004-6361:20053991
| doi-access= free }}
| author1= V. Jaggard
| title= Photo in the News: Sun Probe Spies New Periodic Comet
| url= http://news.nationalgeographic.com/news/2007/09/070925-new-comet.html
| work= National Geographic News
| publisher= National Geographic Society
| date= 25 September 2007
| access-date= 26 September 2007
| archive-date= 11 October 2007
| archive-url= https://web.archive.org/web/20071011195630/http://news.nationalgeographic.com/news/2007/09/070925-new-comet.html
| url-status= dead }}
| title= 322P/SOHO – JPL Small-Body Database Lookup
| url= https://ssd.jpl.nasa.gov/tools/sbdb_lookup.html#/?sstr=322P
| website= ssd.jpl.nasa.gov
| publisher= Jet Propulsion Laboratory
| access-date= 16 August 2023 }}
| author1= M. M. Knight
| author2= A. Fitzsimmons
| author3= M. S. P. Kelley
| author4= C. Snodgrass
| title= Comet 322P/SOHO 1: An asteroid with the smallest perihelion distance?
| url= https://iopscience.iop.org/article/10.3847/2041-8205/823/1/L6/pdf
| journal= The Astrophysical Journal Letters
| year= 2016
| volume= 823
| issue= 1
| pages= 6–12
| bibcode= 2016ApJ...823L...6K
| arxiv= 1604.07790
| doi= 10.3847/2041-8205/823/1/L6
| doi-access= free }}
| author1= G. W. Kronk
| author2= M. Meyer
| author3= D. A. J. Seargent
| title= Cometography: A Catalog of Comets
| url= https://books.google.com/books?id=UzeqxQEACAAJ&pg=PA55
| year= 1999
| volume= 1: Ancient–1799
| publisher= Cambridge University Press
| isbn= 978-0-521-58504-0
| page= 55 }}
| title= 322P/SOHO Orbit
| url= http://www.minorplanetcenter.net/db_search/show_object?object_id=322P
| publisher= Minor Planet Center
| access-date= 10 April 2017 }}
| author1= K. Battams
| title= The Tale of a Very Shy Comet...
| url= https://sungrazer.nrl.navy.mil/index.php?p=news/the_shy_comet
| website= The Sungrazer Project
| date= 30 January 2012
| access-date= 31 January 2012
| archive-date= 3 March 2012
| archive-url= https://web.archive.org/web/20120303205622/https://sungrazer.nrl.navy.mil/index.php?p=news/the_shy_comet
| url-status= dead }}
| title= Periodic Comets identified by SOHO
| url= https://sungrazer.nrl.navy.mil/index.php/periodic_soho
| website= The Sungrazer Project
| access-date= 26 May 2025 }}
|date=2011-09-07
|title=Recent comet discoveries 2123-2137
|publisher=Yahoo Groups: SOHO Hunter
|author=Rainer Kracht
|url=http://tech.groups.yahoo.com/group/sohohunter/message/3444
|archive-url=https://archive.today/20130105111734/http://tech.groups.yahoo.com/group/sohohunter/message/3444
|url-status=dead
|archive-date=January 5, 2013
|access-date=2011-09-11}}
|last = Marsden |first = Brian
|title = MPEC 2007-S16 : COMET P/1999 R1 = 2003 R5 = 2007 R5 (SOHO)
|journal = Minor Planet Electronic Circular
|issue = 2007-S16
|date = 18 September 2007
|url = https://www.minorplanetcenter.net/mpec/K07/K07S16.html }}
|date=25 September 2007
|title=SOHO's new catch: its first officially periodic comet
|publisher=European Space Agency
|url=http://www.esa.int/esaCP/SEMAU2C1S6F_index_0.html
|access-date=2007-11-19}}
|title=322P/SOHO past, present and future orbital elements
|url=http://jcometobs.web.fc2.com/pcmtn/0322p.htm
|work=Comet Orbit
|first=Kazuo |last=Kinoshita
|date=2015-06-09
|access-date=2023-08-16}}
|title=Horizons Batch for 1947-Apr-11 Earth approach uncertainty
|publisher=JPL Horizons
|url=https://ssd.jpl.nasa.gov/horizons_batch.cgi?batch=1&COMMAND=%27322P%27&START_TIME=%271947-Apr-11%2004:00%27&STOP_TIME=%271947-Apr-12%27&STEP_SIZE=%271%20day%27&QUANTITIES=%2720,39%27
|accessdate=2023-08-16}} RNG_3sigma = uncertainty range in km. (JPL#10/Soln.date: 2016-Oct-27)
|title=Horizons Batch for 322P/SOHO on 2023-Aug-21
|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=%27322P%27&START_TIME=%272023-Aug-20%27&STOP_TIME=%272023-Aug-22%27&STEP_SIZE=%271%20hours%27&QUANTITIES=%279,19,22,23%27
|archive-url=https://web.archive.org/web/20230624014734/https://ssd.jpl.nasa.gov/horizons_batch.cgi?batch=1&COMMAND=%27322P%27&START_TIME=%272023-Aug-20%27&STOP_TIME=%272023-Aug-22%27&STEP_SIZE=%271%20hours%27&QUANTITIES=%2719%27
|archive-date=2023-06-24
|url-status=live
|accessdate=2023-08-12}} (JPL#10/Soln.date: 2016-Oct-27)
}}
External links
- {{JPL Small Body|id=1001474}}
- [http://sohowww.nascom.nasa.gov/hotshots/2007_09_24/ SOHO's first officially periodic comet]
- [https://sungrazer.nrl.navy.mil/ SOHO Comets] (view real-time images)
{{PeriodicComets Navigator|321P/SOHO|323P/SOHO}}
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