Observations Of Comet C/2007 (lulin) Before And During Its Perihelion

Tozzi, Gian-Paolo; Brucato, J. R.; Patriarchi, P.; Licandro, J.; Mazzotta Epifani, E.; Snodgrass, C.; Vincent, J.
Bibliographical reference

American Astronomical Society, DPS meeting #42, #28.19; Bulletin of the American Astronomical Society, Vol. 42, p.963

Advertised on:
10
2010
Number of authors
7
IAC number of authors
0
Citations
0
Refereed citations
0
Description
Comet Lulin was observed in July 2008, when the comet was in-bound at 1.7 AU from the Sun. Analysis of the images showed that the comet had a very intense and anomalous enhancement of the column density of the solid components in the inner coma. This effect was before interpreted as due to the presence of sublimating grains (Tozzi et al, 2004, AA, 424, 325; 2007, 476, 979) or, more recently, to a developing coma expanding very slowly (few meters per second, Tozzi et al. 2010, submitted). To disentangle the two phenomena the comet was re-observed in two epochs around its perihelion (Jan - Mar. 2009), when it was at about 1.40 AU from the Sun and at about 0.4 AU from the Earth. In this case the enhancement in the inner coma had disappeared, showing only a wide but less intense enhancement at about 20000-30000 km of projected distance. A possible contamination of gas, that would produce a similar effect, has been excluded by spectra and observations with narrow band filters centred in spectral regions without gas emission. In the presentation the results of the analysis with possible interpretations will be given.