Photometry and imaging of comet 103P/Hartely in the 2010- 2011 apparition

The results of a CARA (Cometary Archive for Afq) campaign on Comet 103P/Hartley 2 are presented. The main goal was to monitor extensively the comet during the apparition with CCD R and I imaging and photometry, as a support of EPOXI mission.
The Afq quantity showed a progressively rising ascending branch, followed by an apparent flat maximum that lasted for 2 months, from about À10 to +50 days from perihelion. In this period, Afq peaked at around 100 cm in R band with strong short term fluctuations between 70 and 140 cm. Early signs of activity were detectable well before perihelion (about 80–90 days before) and a random variability is also present in the descending branch after perihelion. Three post perihelion data points (between +55 and +61 days) from the 1997–1998 apparition show a bit higher Afq value of our observation and a similar fast variation.
The average Afq behavior, corrected for the solar phase effect, is strongly asymmetric and shows a more steeper ascending branch, approaching to perihelion.
Morphology and coma asymmetry, as well as the sunward and tailward profiles are examined. An average gradient indicatively between $qÀ0.7 and qÀ1 is observed in the inner coma (q < 2000 km). Ten small amplitude outbursts have been detected and two ones were suspected

Giannantonio Milani, Paolo Bacci, Walter Borghini, Erik Bryssink, Dario Castellano, Mauro Facchini, Giancarlo Favero, Gianni Galli, Ernesto Guido, Bernhard Hausler, Nick Howes, Rolando Ligustri, Herman Mikuz, Martino Nicolini, Carmen Perrella, Enrico Prosperi, Jure Scvarc, Jiri Srba, Giovanni Sostero, Roberto Trabatti, Carlo Vinante, Gyula Szabò
Soci AAE coinvolti: 
Icarus 222 (2013) 786–798
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