2016MNRAS.456.2622J

The luminous Type IIn Supernova (SN) 2010jl shows strong evidence for the interaction of the SN ejecta with dense circumstellar material (CSM). We present observations of SN 2010jl for t ∼ 900d after its earliest detection, including a sequence of optical spectra ranging from t = 55 to 909d. We also supplement our late time spectra and the photometric measurements in the literature with an additional epoch of new, late time BVRI photometry. Combining available photometric and spectroscopic data, we derive a semi-bolometric optical light curve and calculate a total radiated energy in the optical for SN 2010jl of ∼ 3.5x10⁵⁰erg, confirming the result of Fransson et al. We also examine the evolution of the Hα emission line profile in detail and find evidence for asymmetry in the profile for t ≳ 775d that is not easily explained by any of the proposed scenarios for this fascinating event. Finally, we discuss the interpretations from the literature of the optical and near-infrared light curves, and propose that the most likely explanation of their evolution is the formation of new dust in the dense, pre-existing CSM wind after ∼ 300d.