Comet Machholz

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C/2004 Q2 (Machholz)
Comet Machholz in February 2005
Comet Machholz in February 2005
Discovered by Donald Machholz
Discovery date 2004
Comet Machholz
Orbital characteristics A
Epoch 2453415.5 (February 14, 2005)
Aphelion ~1070 AU[1]
Perihelion 1.205 AU
Semi-major axis ~537 AU[1]
Eccentricity 0.9995
Orbital period 12,400 yr (epoch 2050)[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.


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 2050 generate a semi-major axis of 537 AU and a period of approximately 12,400 years.[1] This gives it a barycentric orbital period just a little larger than Sedna.


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

See also[edit]


  1. ^ a b c d Horizons output. "Barycentric Osculating Orbital Elements for Comet C/2004 Q2 (Machholz)". Retrieved 2011-02-03.  (Solution using the Solar System Barycenter and barycentric coordinates. Select Ephemeris Type:Elements and Center:@0)

External links[edit]