168P/Hergenrother

On 22 November 1998, Carl W. Hergenrother spotted a new comet from CCD images taken by Timothy B. Spahr a day earlier with the Catalina Sky Survey's {{cvt|0.41|m|in}} telescope.{{r|cometography}} Preliminary orbital calculations by Brian G. Marsden reveal that the comet has a periodic orbit of 6.78 years.{{r|IAUC_7057}} At the time, the comet was a 17th-magnitude object within the constellation Ursa Minor.{{efn|Reported initial position upon discovery was: α {{=}} {{RA|21|15|03.67}}, δ {{=}} {{DEC|–14|37|45}}{{r|IAUC_7057}}}}

Between 2000 and 2002, Kazuo Kinoshita and Shuichi Nakano independently used the comet's positions during its 1998 apparition to predict its next perihelion date, which is around 2 November 2005.{{r|cometography}} It was successfully recovered by Australian astronomer, David Herald, on 6 November 2005.{{r|IAUC_8560}}

The comet came to perihelion on 1 October 2012,{{r|NK1778}} and was expected to reach about apparent magnitude 15.2, but due to an outburst the comet reached apparent magnitude 8.{{r|Yoshida_2012}} As a result of the outburst of gas and dust, the comet was briefly more than 500 times brighter than it would have been without the outburst.{{efn|Apparent magnitude: $(\backslash sqrt[5]\{100\})^\{15.2-8\}\backslash approx\; 758$}} On 19 October, images by the Virtual Telescope Project showed a dust cloud trailing the nucleus.{{r|Masi_2012}} Images by the {{cvt|2|m|in}} Faulkes Telescope North on 26 October,{{r|jpl2}} confirm a fragmentation event.{{r|Sostero_2012}} The secondary fragment was about magnitude 17. Further observations by the {{cvt|8.1|m|in}} Gemini telescope show that the comet fragmented into at least four parts in six fragmentation events.{{r|jpl2|Plait_2012|Sekanina_2014}}

168P came to perihelion on 5 August 2019,{{r|MPC}} when it was 76 degrees from the Sun. It then made a closest approach to Earth on 6 November 2019, when it was {{Convert|1|AU|e6km|abbr=unit}} from Earth with a solar elongation of about 110 degrees. It was not recovered until 3 January 2020, when it was 141 degrees from the Sun, but only two observations on a single night were reported.

Observations conducted by the Spitzer Space Telescope between 2006 and 2007 showed that Hergenrother's nucleus was originally about {{cvt|0.96|km|mi}} in diameter before it disintegrated on its 2012 outburst.{{r|Fernandez_2013}} This was later revised to {{cvt|0.91|km|mi}} upon reanalysis of data in 2020.{{r|Paradowski_2020}}

{{Notelist}}

{{reflist|refs=

{{cite web

| author1= G. W. Kronk

| title= 168P/Hergenrother

| url= https://cometography.com/pcomets/168p.html

| website= Cometography.com

| access-date= 1 April 2025 }}

{{cite journal

| author1= C. W. Hergenrother

| editor1= B. G. Marsden

| title= Comet C/1998 W2 (Hergenrother)

| url= http://www.cbat.eps.harvard.edu/iauc/07000/07057.html

| journal= IAU Circular

| volume= 7057

| date= 23 November 1998 }}

{{cite journal

| author1= Y. R. Fernández

| author2= M. S. Kelley

| author3= P. L. Lamy

| author4= I. Toth

| author5= O. Groussin

| author6= C. M. Lisse

| author7= M. F. A’Hearn

| author8= J. M. Bauer

| author9= H. Campins

| author10= A. Fitzsimmons

| author11= J. Licandro

| author12= S. C. Lowry

| author13= K. J. Meech

| author14= J. Pittichová

| author15= W. T. Reach

| author16= C. Snodgrass

| author17= H. A. Weaver

| display-authors= 5

| title= Thermal Properties, Sizes, and Size Distribution of Jupiter-family Cometary Nuclei

| url= https://arxiv.org/pdf/1307.6191

| journal= Icarus

| year= 2013

| volume= 226

| issue= 1

| pages= 1138–1170

| bibcode= 2013Icar..226.1138F

| arxiv= 1307.6191

| doi= 10.1016/j.icarus.2013.07.021 }}

{{cite journal

| author1= D. Herald

| editor1= D. W. Green

| title= Comet P/2005 N2 (Hergenrother)

| url= http://www.cbat.eps.harvard.edu/iauc/08500/08550.html

| journal= IAU Circular

| volume= 8560

| date= 5 July 2005 }}

{{cite web

| title= 168P/Hergenrother – JPL Small-Body Database Lookup

| url= https://ssd.jpl.nasa.gov/tools/sbdb_lookup.html#/?sstr=168P

| website= ssd.jpl.nasa.gov

| publisher= Jet Propulsion Laboratory

| access-date= 1 April 2025 }}

{{cite web

| author1= D. C. Agle

| title= Scientists Monitor Comet Break-up

| website= jpl.nasa.gov

| publisher= Jet Propulsion Laboratory

| url= https://www.jpl.nasa.gov/news/scientists-monitor-comet-breakup/

| date= 2 November 2012

| access-date= 1 April 2025

| id= 2012-349 }}

{{cite web

| author1= G. Masi

| title= Comet 168P/Hergenrother: hi-res images (19 Oct. 2012)

| url= http://www.virtualtelescope.eu/2012/10/22/comet-168phergenrother-hi-res-images-19-oct-2012/

| work= Virtual Telescope Project

| date= 19 October 2012

| access-date= 18 October 2016 }}

{{cite web

| title= 168P/Hergenrother Orbit

| url= http://www.minorplanetcenter.net/db_search/show_object?object_id=168P

| publisher= Minor Planet Center

| access-date= 20 June 2014 }}

{{cite web

| author1= S. Nakano

| title= 168P/Hergenrother (NK 1778)

| publisher= OAA Computing and Minor Planet Sections

| url= http://www.oaa.gr.jp/~oaacs/nk/nk1778.htm

| date= 23 April 2009

| access-date= 20 February 2012 }}

{{cite journal

| author1= M. L. Paradowski

| title= A New Method of Determining Brightness and Size of Cometary Nuclei

| url= https://academic.oup.com/mnras/article-pdf/492/3/4175/32217737/stz3597.pdf

| journal= Monthly Notices of the Royal Astronomical Society

| year= 2020

| volume= 492

| issue= 3

| pages= 4175–4188

| bibcode= 2020MNRAS.492.4175P

| doi= 10.1093/mnras/stz3597

| doi-access= free }}

{{cite web

| author1= P. Plait

| title= Breaking up is easy to do. If you're a comet

| url= http://blogs.discovermagazine.com/badastronomy/2012/11/05/breaking-up-is-easy-to-do-if-youre-a-comet/

| website= Bad Astronomy

| date= 5 November 2012

| access-date= 6 November 2012

| archive-date= 8 November 2012

| archive-url= https://web.archive.org/web/20121108035433/http://blogs.discovermagazine.com/badastronomy/2012/11/05/breaking-up-is-easy-to-do-if-youre-a-comet/

| url-status= dead }}

{{cite arxiv

| author1= Z. Sekanina

| title= Temporal Correlation Between Outbursts and Fragmentation Events of Comet 168P/Hergenrother

| year= 2014

| arxiv= 1409.7641

| class= astro-ph.EP }}

{{cite web

| author1= G. Sostero

| author2= N. Howes

| author3= E. Guido

| title= Splitting event in comet 168P/Hergenrother

| url= http://remanzacco.blogspot.it/2012/10/splitting-event-in-comet.html

| publisher= Remanzacco Observatory in Italy – Comets & Neo

| date= 26 October 2012

| access-date= 28 October 2012 }}

{{cite web

| author1= S. Yoshida

| title= 168P/Hergenrother (2012)

| url= http://www.aerith.net/comet/catalog/0168P/2012.html

| website= www.aerith.net

| date= 21 February 2012

| access-date= 25 February 2012 }}

}}

• {{JPL Small Body|id=1000242}}
• {{MPC|168P|168P/Hergenrother}} at the Minor Planet Center
• [http://www.aerith.net/comet/catalog/0168P/index.html 168P on Seiichi Yoshida's comet list]
• [https://www.youtube.com/watch?v=aFcwzQe_hHc Comet 168P Hergenrother in outburst] (Google+ chat archive Oct 12, 2012)
• [http://transientsky.wordpress.com/2012/10/20/comet-hergenrother-in-outburst/ Comet Hergenrother in Outburst] (Carl Hergenrother : 20 Oct 2012)
• [http://podideployment.blogspot.co.uk/2012/10/a-comet.html Comet 168P and fragment] as seen by Kitt Peak WIYN {{convert|3.5|m|in|adj=on}} on 30 Oct 2012

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Category:Periodic comets

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