Comet Machholz

Not to be confused with 96P/Machholz or 141P/Machholz 2.

There are five other long-period comets named Machholz: C/1978 R3 (a.k.a. 1978 XIII, 1978l), C/1985 K1 (a.k.a. 1985 VIII, 1985e), C/1988 P1 (a.k.a. 1988 XV, 1988j), C/1992 N1 (a.k.a. 1992 XVII, 1992k) and C/1994 T1 (a.k.a. 1994 XXVII, 1994r).

C/2004 Q2 (Machholz)

Comet Machholz in February 2005
Discovery
Discovered by:	Donald Machholz
Discovery date:	2004
Alternate designations:	Comet Machholz
Orbital characteristics A
Epoch:	2453415.5 (February 14, 2005)
Aphelion distance:	~1070 AU[1]
Perihelion distance:	1.205 AU
Semi-major axis:	~537 AU[1]
Eccentricity:	0.9995
Orbital period:	12,500 yr[1]
Inclination:	38.6°
Last perihelion:	January 24, 2005
Next perihelion:	unknown

Comet Machholz, formally designated C/2004 Q2, is a long-period comet discovered by Donald Machholz on August 27, 2004.

It reached naked eye brightness in January 2005. Unusual for such a relatively bright comet, its perihelion was farther from the Sun than the Earth's orbit.

Period

Given the orbital eccentricity of this object, different epochs can generate quite different heliocentric unperturbed two-body best-fit solutions to the aphelion distance (maximum 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 2011-Jan-01 generate a semi-major axis of 537 AU and a period of approximately 12,500 years.^[1] This gives it a barycentric orbital period just a little larger than Sedna.

Image

Comet Machholz appears to pass near the Pleiades cluster in early 2005

See also

• 96P/Machholz (a.k.a. 1986 VIII, 1986e, 1991 XII)
• 141P/Machholz 2 (a.k.a. 1994 XXVI, 1994o)
• C/1992 F1 (a.k.a. 1992 X, 1992d), Comet Tanaka-Machholz
• C/1994 N1 (a.k.a. 1994 XX, 1994m), Comet Nakamura-Nishimura-Machholz

References

1. ^ ^{a b c d} Horizons output. "Barycentric Osculating Orbital Elements for Comet C/2004 Q2 (Machholz)". http://ssd.jpl.nasa.gov/horizons.cgi?find_body=1&body_group=sb&sstr=C/2004+Q2. Retrieved 2011-02-03.  (Solution using the Solar System Barycenter and barycentric coordinates. Select Ephemeris Type:Elements and Center:@0)

External links

• NASA JPL Small-Body Database Browser on C/2004 Q2
• Sky and Telescope — Comet Machholz in the Evening Sky
• Sky and Telescope — Catch Comet Machholz at Its Best
• The Discovery of Comet Machholz (discoverer's personal retelling)
• Gallery of images