View source for C/2020 F8 (SWAN)

{{short description|Second brightest naked-eye comet of 2020}}
{{Use mdy dates|date=May 2020}}
{{Infobox comet
|name  = C/2020 F8
|image = C2020 F8 (SWAN) on 1 May from Indonesia.jpg
|caption=Comet C/2020 F8 (SWAN) on May 1, 2020 from Indonesia
|discoverer=Solar and Heliospheric Observatory (SOHO)
|designations=SWAN01{{citation needed|date=January 2023}}
|discovery_date= 25 March 2020<ref name="UT"/>
|epoch=2020-Apr-26<br/>(JD 2458965.5)
|observation_arc=42 days
|orbit=[[Oort cloud]]
|aphelion=~1300 [[Astronomical unit|AU]] (outbound)
|perihelion={{Convert|0.4303|AU|e6km|abbr=unit|lk=on|sigfig=2}}
|eccentricity=0.99994
|period=[[Hyperbolic trajectory]] (inbound)<br/>~17000 years (outbound)
|inclination=110.8
|Earth_moid={{Convert|0.1937|AU|e6km LD|abbr=unit|lk=on|sigfig=2}}
| Jupiter_moid  = 2.35 AU
| physical_ref  = {{r|Jewitt_2022}}
| dimensions    = {{cvt|0.4|–|0.8|km|mi}}
| mean_diameter = {{cvt|0.6|km|mi}}
| M1            = 
| M2            = 
| magnitude     = 4.7<br>{{small|(2020 apparition)}}
| last_p        = 27 May 2020
}}

'''C/2020 F8 (SWAN)''', or '''Comet SWAN''', is an [[Oort cloud]] [[comet]] that was discovered in images taken by the Solar Wind Anisotropies (SWAN) camera on 25 March 2020, aboard the [[Solar and Heliospheric Observatory|Solar and Heliospheric Observatory (SOHO)]] spacecraft.<ref name=MPC>{{Cite web|url=https://minorplanetcenter.net/mpec/K20/K20G94.html|title=MPEC 2020-G94 : COMET C/2020 F8 (SWAN)|website=minorplanetcenter.net|access-date=April 16, 2020}}</ref><ref name="UT">{{Cite web|url=https://www.universetoday.com/145617/comet-y4-atlas-breaks-up-enter-comet-f8-swan/|title=Comet Y4 ATLAS Breaks Up...Enter Comet F8 SWAN|date=April 15, 2020|website=Universe Today|language=en-US|access-date=April 16, 2020}}</ref> In the glare of [[twilight]], Comet SWAN is difficult to find with [[Binoculars#Objective_diameter|50mm binoculars]] even though it is still near the theoretical range of naked eye visibility. The comet has dimmed since May 3.<ref name=COBS/> As of perihelion, the comet is very diffuse, does not have a visible [[Comet nucleus|nucleus]] and is not a comet that will be noticed by inexperienced observers. It is likely that the comet disintegrated.

== Observing ==
On April 28, 2020 it had an [[apparent magnitude]] of 7 and was too diffuse to be visible to the naked eye even from a dark site.<ref name=COBS/> The comet was also hidden by the glare of [[twilight]], [[zodiacal light]] and [[atmospheric extinction]]. It was originally best seen from the [[Southern hemisphere|Southern Hemisphere]]. It was expected to possibly reach 3rd magnitude in May, but instead hovered closer to magnitude 6.<ref name=Yoshida/> In either case it was near the glare of twilight, which made it appear significantly fainter.<ref name=Yoshida/> On May 2, the comet had reached a magnitude of 4.7 and had been detected with [[naked eye]],<ref>{{cite web |title=Comet C/2020 F8 (SWAN) observation list |url=https://cobs.si/cobs/comet/obs/1876/ |website=cobs.si |access-date=22 January 2023}}</ref> the tail had a visual length of one degree and could be traced photographically for 6-8 degrees.<ref>{{cite web |last1=King |first1=Bob |title=Comet SWAN Expected to Put on a Splendid Show |url=https://skyandtelescope.org/astronomy-news/comet-swan-expected-to-put-on-a-splendid-show/ |website=Sky & Telescope |access-date=6 January 2022 |date=6 May 2020}}</ref> After that the comet faded, probably as the nucleus of the comet fragmented.<ref>{{cite journal |author1=Joe Rao |title=Newfound Comet SWAN could soon fizzle out of view |website=Space.com |date=12 May 2020 |url=https://www.space.com/comet-swan-may-be-dimming.html |access-date=22 January 2023 |language=en}}</ref><ref>{{cite web |last1=King |first1=Bob |title=Comet SWAN's Final Song |url=https://skyandtelescope.org/astronomy-news/comet-swan-song/ |website=Sky & Telescope |access-date=22 January 2023 |date=22 May 2020}}</ref> It passed through the [[celestial equator]] on 7 May, then it headed northward and it was near the 2nd magnitude star [[Algol]] on 20 May.<ref name="UT" /> It passed its perihelion on May 27, 2020.
:[[File:C2020_F8-skypath.png|left|thumb|250x250px|Sky trajectory with 7 week markers]]
:
{{clear|left}}

== Orbit ==
[[File:C 2020 F8 SWAN.jpg|thumb|left|250px|C/2020 F8 (SWAN)'s orbit]]
The [[Minor Planet Center]] initially listed the orbit as bound with <math>e<1</math>.<ref name=MPC/> With a short 18-day [[observation arc]] [[Jet Propulsion Laboratory|JPL]] listed the comet as [[Hyperbolic trajectory|hyperbolic]] with an eccentricity of {{val|1.0009|0.001}}, but a longer observation arc was needed to refine the uncertainties and either confirm its hyperbolic trajectory, or determine its orbital period of thousands or millions of years.<ref name=jpldata/> With a 40-day observation arc it was possible to determine that it came from the [[Oort cloud]] on a [[Hyperbolic trajectory]] and that the outbound orbit will last ~11,000 years.

On May 12, 2020, the comet passed about {{Convert|0.56|AU|e6km LD|abbr=unit|lk=on}} from Earth. On May 27, 2020 the comet came to [[perihelion]] {{Convert|0.43|AU|e6km|abbr=unit|lk=on}} from the Sun.<ref name=MPC/>

{{clear}}

== Gallery ==
<gallery mode=nolines widths=220px heights=220px>
File:SWAN 2-5-2020.jpg|Photo taken on May 2, 2020<ref name="photo" />
</gallery>

==References==
{{reflist|refs=

<ref name=Yoshida>{{cite news
  |author=Seiichi Yoshida
  |title=C/2020 F8 ( SWAN )
  |date=April 13, 2020
  |url=http://www.aerith.net/comet/catalog/2020F8/2020F8.html
  |access-date=April 16, 2020}}</ref>

<ref name="Jewitt_2022">{{cite journal
| author1= D. C. Jewitt
| title= Destruction of Long-period Comets
| url= https://iopscience.iop.org/article/10.3847/1538-3881/ac886d/pdf
| journal= Astronomical Journal 
| year= 2022
| volume= 164
| issue= 4
| pages= 158–166
| bibcode= 2022AJ....164..158J
| arxiv= 2208.04469
| doi= 10.3847/1538-3881/ac886d
| doi-access= free }}
</ref>

<ref name=jpldata>{{cite web
  |title=JPL Small-Body Database Browser: C/2020 F8 (SWAN)
  |url=https://ssd.jpl.nasa.gov/sbdb.cgi?sstr=2020F8
  |publisher=[[Jet Propulsion Laboratory]]
  |access-date=April 30, 2020
  |archive-url=https://archive.today/20200417034445/https://ssd.jpl.nasa.gov/sbdb.cgi?sstr=2020F8
  |archive-date=April 17, 2020 |url-status=live
  }}</ref>

<ref name=COBS>{{cite web
  |title=Comet Observation database (COBS)
  |last1=Ghosh
  |first1=Trinankur
  |url=http://www.cobs.si/
  |access-date=April 28, 2020
  }} [https://cobs.si/analysis2?col=comet_id&id=1876&plot_type=0 "C/2020 F8 (SWAN) plot"] {{Webarchive|url=https://web.archive.org/web/20200610170415/https://cobs.si/analysis2?col=comet_id&id=1876&plot_type=0 |date=June 10, 2020 }}</ref>

<ref name=photo>{{cite web
|author=Diego Toscan
|url=https://www.instagram.com/p/B_wHCBJF6eK/
 |archive-url=https://ghostarchive.org/iarchive/s/instagram/B_wHCBJF6eK |archive-date=2021-12-24 |url-access=limited|title=Comet C/2020 F8 SWAN 2 May 2020 
|access-date=May 4, 2020}}{{cbignore}}</ref>

}}

== External links ==
* [http://www.aerith.net/comet/catalog/2020F8/2020F8.html C/2020 F8 (SWAN)] – Seiichi Yoshida
* [https://ssd.jpl.nasa.gov/sbdb.cgi?sstr=C%2F2020%20F8 C/2020 F8 (SWAN)] – JPL
* [https://twitter.com/Komet123Jager/status/1267716589782253568 C/2020 F8 Swan on June 1] (without a defined nucleus) – Michael Jäger
* [http://aim-muenster.de/AiM-Project-Group/Some-Impressions/Comet-C/2020-F8-SWAN/ C/2020 F8 (SWAN)] {{Webarchive|url=https://web.archive.org/web/20200629113128/http://aim-muenster.de/AiM-Project-Group/Some-Impressions/Comet-C/2020-F8-SWAN/ |date=June 29, 2020 }} – AiM-Project

{{2020 in space}}
{{Comets}}
{{Authority control}}

{{DEFAULTSORT:SWAN, 2020 F8}}
[[Category:Astronomical objects discovered in 2020]]
[[Category:Comets in 2020]]
[[Category:Non-periodic comets]]
[[Category:Destroyed comets]]
[[Category:Oort cloud]]