SN 2009ip: constraints on the progenitor mass-loss rate

Official URL: http://dx.doi.org/ 10.1088/0004-637X/768/1/47

Some supernovae (SNe) show evidence for mass-loss events taking place prior to their explosions. Measuring their pre-outburst mass-loss rates provides essential information regarding the mechanisms that are responsible for these events. Here we present XMM-Newton and Swift X-ray observations taken after the latest, and presumably the final, outburst of SN 2009ip. We use these observations as well as new near-infrared and visible-light spectra and published radio and visible-light observations to put six independent order-of-magnitude constraints on the mass-loss rate of the SN progenitor prior to the explosion. Our methods utilize the X-ray luminosity, the bound-free absorption, the H alpha luminosity, the SN rise time, free-free absorption, and the bolometric luminosity of the outburst detected prior to the explosion. Assuming spherical mass loss with a wind-density profile, we estimate that the effective mass-loss rate from the progenitor was between 10(-3) and 10(-2) M-circle dot yr(-1), over a few years prior to the explosion, with a velocity of similar to 10(3) km s(-1). This mass-loss rate corresponds to a total circumstellar matter (CSM) mass of similar to 0.04 M-circle dot, within 6 x 10(15) cm of the SN. We note that the mass-loss rate estimate based on the H alpha luminosity is higher by an order of magnitude. This can be explained if the narrow-line H alpha component is generated at radii larger than the shock radius, or if the CSM has an aspherical geometry. We discuss simple geometries which are consistent with our results.