Time-Varying Potassium in High-Resolution Spectra of the Type Ia Supernova 2014J

TL;DR

This study provides high-resolution, time-series spectra of SN 2014J, revealing stable interstellar features but weakening of some circumstellar potassium lines, suggesting photoionization effects related to the supernova's progenitor environment.

Contribution

First high-resolution, multi-epoch spectral analysis of SN 2014J revealing temporal changes in potassium absorption features and implications for progenitor models.

Findings

No evolution in Na I D, Ca I, or DIBs.

Weakening of the blueshifted K I components.

Supports photoionization of circumstellar material hypothesis.

Abstract

We present a time series of the highest resolution spectra yet published for the nearby Type Ia supernova (SN) 2014J in M82. They were obtained at 11 epochs over 33 days around peak brightness with the Levy Spectrograph (resolution R~110,000) on the 2.4m Automated Planet Finder telescope at Lick Observatory. We identify multiple Na I D and K I absorption features, as well as absorption by Ca I H & K and several of the more common diffuse interstellar bands (DIBs). We see no evolution in any component of Na I D, Ca I, or in the DIBs, but do establish the dissipation/weakening of the two most blueshifted components of K I. We present several potential physical explanations, finding the most plausible to be photoionization of circumstellar material, and discuss the implications of our results with respect to the progenitor scenario of SN 2014J.