FIRST FINDINGS ON COMETARY ACTIVITY FROM THE PTF COMET SAMPLE

Abstract

We present preliminary results from the Palomar Transient Factory (PTF) uniform sample of short period comets (SPCs) and long period comets (LPCs), captured between September 2009 and March 2013. We study their dynamical and physical properties in relation to their activity for a better understanding of cometary evolution. This observing campaign was part of PTF in its intermediate phase (iPTF) at the California Institute of Technology (Caltech). The photometric sample comprises more than 180 comets, which makes it one of the largest samples studied to-date. We present a new approach to identifying active comets that compares subtracted aperture magnitudes of comets with the distribution of stars of similar brightness in each image. In this paper, we present initial findings on cometary activity in relationship to their perihelion distances. We show differences between the distributions of the SPCs and that of the LPCs. As others predicted, it seems that a larger fraction of LPCs are found to be active at larger perihelia than for the SPCs. We look at ratios of active comets in different perihelia brackets and compare those to previous works and results. We do not discuss the statistical significance of our findings as this is still work in progress.