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C.M. Lisse, T.L. Farnham (University of Maryland), Y.R. Fernandez (University of Hawaii), G.R. Lawrence (NASA/GSFC), G.H. Jones (NASA/JPL), J.S. Morill, M.D. Andrews, D. Hammer (NRL)
The joint NASA/ESA solar observatory SOHO mission observed long period comet C/2002 V1 (NEAT) in 4 broad band optical/near-IR filters using the LASCO C3 imager on February 16 - 20, 2003. During this time of the comet's extremely close perihelion passage (q = 0.1 AU), the line of sight to the comet was nearly perpendicular to the comet's orbit plane, providing an excellent separation of the dust tail syndynes and synchrones.
Our preliminary results are extraordinary - the comet exhibited the brightest and largest (~ 107 km long) SOHO dust tail to date, with a peak gas production rate of ~ 1031 mol/sec, similar to the huge rates found from C/1995 O1 Hale-Bopp and 96P/Machholz 1 at perihelion. A large CME emanating from the Sun appears to have struck the comet on February 18, affecting not only the ion gas tail, the first to be detected in a SOHO image, but the dust tail as well. The most probable cause of the dust tail perturbation is solar wind charging of the dust by the CME ion burden, but other mechanisms are also possible, such as dust disruption or dust emission enhancement. Pronounced, highly regular striae are found emanating through the dust tail, most probably due to signatures of rotation, but possibly due instead to fragmentation of the nucleus or solar wind spatial structures.
Here we present the SOHO images and light curves for the comet, and discuss the most likely physical explanation for the observed behavior in the dust and ion tails.
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Bulletin of the American Astronomical Society, 35 #4
© 2003. The American Astronomical Soceity.