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Issue A&A
Volume 469, Number 2, July II 2007
Page(s) 771 - 776
Section Planets and planetary systems
DOI http://dx.doi.org/10.1051/0004-6361:20077286



A&A 469, 771-776 (2007)
DOI: 10.1051/0004-6361:20077286

Photometry and imaging of comet C/2004 Q2 (Machholz) at Lulin and La Silla

Z. Y. Lin1, M. Weiler2, H. Rauer2, and W. H. Ip1

1  Institute of Astronomy, National Central University, 300 Jungda Rd, Jungli City, Taiwan
    e-mail: s1249002@cc.ncu.edu.tw
2  Institut fur Planetenforschung, DLR, Rutherfordstr. 2, 12489 Berlin, Germany

(Received 13 February 2007 / Accepted 20 March 2007)

Abstract
Aims.We have investigated the development of the dust and gas coma of the comet C/2004 Q2 (Machholz) from December 2004 to January 2005 using observations obtained at the Lulin Observatory, Taiwan and the European Southern Observatory at La Silla, Chile.
Methods.We determined the dust-activity parameter $Af\rho$ and the dust color and derived Haser production rates and scale lengths of $\rm C_2$ and $\rm NH_2$. An image enhancement technique was applied to study the morphology of the gas and dust coma.
Results.Two jets were observed in the coma distributions of $\rm C_2$ and CN of comet Machholz that were not formed in the dust coma. The jets showed a spiral-like structure and pointed at different position angles at different observing times. The formation of these jets can be explained by the presence of two active surface regions on a rotating cometary nucleus.


Key words: comets: indvidual: C/2004Q2 (Machholz)



© ESO 2007

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