C/2006 M4 (SWAN)
{{Short description|Non-periodic comet}}
{{For|other comets discovered by SWAN|Comet SWAN (disambiguation){{!}}Comet SWAN}}
{{Infobox comet
| name = C/2006 M4 (SWAN)
| image = Comet SWAN - 276705774.jpg
| caption = Comet SWAN in an outburst as photographed on 22 October 2006
| discoverer = Robert D. Matson
Michael Mattiazzo
| discovery_site = SOHO (SWAN)
| discovery_date = 20 June 2006
| designations =
| orbit_ref = {{r|barycenter|jpl}}
| epoch = 10 November 2006 (JD 2454049.5)
| orbit = Oort cloud
| perihelion = 0.783 AU
| aphelion = ~9,800 AU (inbound)
~2,640 AU (outbound)
| semimajor = 1,300 AU
| period = ~340,000 years (inbound)
~48,000 years (outbound)
| eccentricity = 0.9998
| inclination = 111.82°
| asc_node = 148.73°
| arg_peri = 62.594°
| mean =
| tjup =
| Earth_moid = 0.070 AU
| Jupiter_moid = 1.089 AU
| physical_ref = {{r|jpl}}
| M1 = 11.0
| M2 =
| magnitude = 4.0
{{small|(2006 apparition)}}
| last_p = 28 September 2006{{r|mpceph}}
| next_p =
}}
C/2006 M4 (SWAN) is a non-periodic comet discovered in late June 2006 by Robert D. Matson of Irvine, California and Michael Mattiazzo of Adelaide, South Australia in publicly available images of the Solar and Heliospheric Observatory (SOHO). These images were captured by the Solar Wind ANisotropies (SWAN) Lyman-alpha all-sky camera on board the SOHO. The comet was officially announced after a ground-based confirmation by Robert McNaught (Siding Spring Survey) on July 12.{{r|MPEC_2006-N38}}
Although perihelion was reached on 28 September 2006,{{r|mpceph}} the comet flared dramatically from an outburst, resulting in its apparent magnitude to increase from 7.0 to 4.0 on 24 October 2006, becoming visible with the naked eye.{{r|cometography|skytel1}}
Orbit
Comet C/2006 M4 is in a hyperbolic trajectory (with an osculating eccentricity larger than 1){{r|mpceph}} during its passage through the inner Solar System. After leaving the influence of the planets, the eccentricity will drop below 1 and it will remain bound to the Solar System as an Oort cloud comet.
Given the extreme orbital eccentricity of this object, different epochs can generate quite different heliocentric unperturbed two-body best-fit solutions to the aphelion distance of this object. For objects at such high eccentricity, the Suns barycentric coordinates are more stable than heliocentric coordinates. Using JPL Horizons, the barycentric orbital elements for epoch 2013-May-14 generate a semi-major axis of about {{convert|1300|AU|e9km|abbr=unit}} and a period of about 48,000 years.{{r|barycenter}}
References
{{Reflist|refs=
| author= Horizons output
| url= https://ssd.jpl.nasa.gov/horizons_batch.cgi?batch=1&COMMAND=%272006+M4%27&TABLE_TYPE=%27ELEMENTS%27&START_TIME=%271800-01-01%27&STOP_TIME=%272200-01-01%27&STEP_SIZE=%27200%20years%27&CENTER=%27@0%27&OUT_UNITS=%27AU-D%270-01-01%27&STEP_SIZE=%27200%20years%27&CENTER=%27@0%27&OUT_UNITS=%27AU-D%27
| title= Barycentric Osculating Orbital Elements for Comet C/2025 F2 (SWAN)
| website= ssd.jpl.nasa.gov
| access-date= 31 January 2011 }}
| author1= G. W. Kronk
| title= C/2006 M4 (SWAN)
| url= https://cometography.com/lcomets/2006m4.html
| website= Cometography.com
| access-date= 10 April 2025 }}
| title= C/2006 M4 (SWAN) – JPL Small-Body Database Lookup
| url= https://ssd.jpl.nasa.gov/tools/sbdb_lookup.html#/?sstr=2006M4
| website= ssd.jpl.nasa.gov
| publisher= Jet Propulsion Laboratory
| access-date= 10 April 2025 }}
| author= B. G. Marsden
| title= MPEC 2006-N38: COMET C/2006 M4 (SWAN)
| url= http://www.minorplanetcenter.net/mpec/K06/K06N38.html
| publisher= Minor Planet Center
| date= 15 July 2006
| access-date= 31 January 2011 }}
| type= Epoch 22 September 2006
| title= Elements and Ephemeris for C/2006 M4 (SWAN)
| url= http://scully.cfa.harvard.edu/cgi-bin/returnprepeph.cgi?d=c&o=CK06M040
| access-date= 31 January 2011 }}
{{dead link
| date= January 2018
| bot= InternetArchiveBot
| fix-attempted= yes }}
| author1= A. MacRobert
| title= Comet SWAN Still Glows After Dusk
| url= http://www.skyandtelescope.com/observing/home/4477131.html
| website= Sky & Telescope
| date= 20 November 2006
| access-date= 31 January 2011
| archive-date= 3 February 2013
| archive-url= https://archive.today/20130203072136/http://www.skyandtelescope.com/observing/home/4477131.html
| url-status= dead }}
}}
External links
- {{JPL Small Body|id=1002407}}
- [http://www.aerith.net/comet/catalog/2006M4/2006M4.html C/2006 M4 ( SWAN )] @ Seiichi Yoshida (September 21, 2007)
{{Comets}}
{{Authority control}}
{{DEFAULTSORT:SWAN, 2006 M4}}
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