Optical Photometry of the Type II-P Supernova 2004dj in NGC 2403

Abstract

We present photometric data of the Type II-P supernova (SN) 2004dj in NGC 2403. The multicolor light curves cover the SN from ∼60 to 200 days after explosion and are measured with a set of intermediate-band filters that have the advantage of tracing the strength variations of some spectral features. The light curves show a flat evolution in the middle of the plateau phase, then decline exponentially at the late times, with a rate of 0.10 ± 0.03 mag (10 days) -1 in most of the filters. In the nebular phase, the spectral energy distribution of SN 2004dj shows a steady increase in the flux near 6600 and 8500 Å, which may correspond to the emission lines of Hα and the Ca II near-IR triplet, respectively. The photometric behavior suggests that SN 2004dj is a normal SN II-P. Compared with the light curves of another typical SN II-P, 1999em, we estimate the explosion date to be 2004 June 10 ± 21 UT (JD 2,453,167 ± 21) for SN 2004dj. We also estimate the ejected nickel mass during the explosion to be M( 56 Ni) = 0.023 ± 0.005 M ⊙ from two different methods, which is typical for a SN II-P. We derive the explosion energy to be E ≈ 0.75 -0.38 +0.56 × 10 51 ergs, the ejecta mass to be M ≈ 10.0 -5.2 +7.4 M ⊙ , and the initial radius to be R ≈ 282 -122 +253 R ⊙ for the presupernova star of SN 2004dj, which are consistent with other typical SNe II-P. © 2006. The American Astronomical Society. All rights reserved.