Photometry and imaging of Comet 103P/Hartley in the 2010–2011 apparition

Un altro traguardo raggiunto dagli astrofili che collaborano con la ricerca.

Nell'ambito del Progetto CARA due nostri soci (Giannantonio Milani e Carlo Vinante) sono coinvolti in progetti di ricerca internazionali, sulle comete.
In pubblicazione sul numero di Febbraio di Icarus (Elsevier) un articolo sulla cometa 103P dal titolo Photometry and imaging of Comet 103P/Hartley in the 2010–2011 apparition.

a b s t r a c t

The results of a CARA (Cometary Archive for Afρ) 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 Afρ quantity showed a progressively rising ascending branch, followed by an apparent flat maximum that lasted for 2 months, from about -10 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 Afρ value of our observation and a similar fast variation.

The average Afρ 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 ~ ρ^0.7 and ρ¹ is observed in the inner coma (ρ < 2000 km). Ten small amplitude outbursts have been detected and two ones were suspected.