Poster abstract details

In our Spitzer 24 $\mu$m survey of hot white dwarfs (WDs) we found 9 WDs with IR excesses, 7 of them are still central stars of planetary nebulae (CSPNs). We have also carried out a Spitzer archival study of CSPNs, and found additional objects with IR excesses. To date, a total of $\sim$15 CSPNs show IR excesses from Spitzer observations. These mid-IR excesses are indicative of the presence of circumstellar dust, which could be produced by collisions or disruption of sub-planetary objects. To further assess the nature of these IR-excesses, we have obtained Spitzer IRS, Gemini NIRI and Michelle, and KPNO 4m echelle spectra of these objects. In this poster, we present the analysis of these spectroscopic observations and discuss the nature of these IR excesses.