Photometry of four long-period comets

In this work we studied the activity of four long period comets at different heliocentric distances in order to explore their dust production and characteristics. The targets were the comets C/2011 A3 (Gibbs), C/2012 K1 (PanStarrs), C/2012 LP26 (Palomar) and C/2013 F3 (McNaught). Some of these objects have never been studied before. We analyzed images in V and R filters taken with the 2.15 m telescope at Complejo Astron = omico El Leoncito (CASLEO), Argentina, to characterize their dust coma features and to investigate the morphology, photometry and dust production. The morphological analysis showed some differences among the sample while the Af rho values measured in a reference aperture of radius rho = 104 km showed a scenario of bodies that fit the profile of a long period comet. This is corroborated by the Minor Planet Center dynamical classification.