PI: Jana Bilikova, University of Illinois, email@example.com
Address: Astronomy Department, 1002 West Green Street, Urbana, IL 61801, USA
CoI: You-Hua Chu, University of Illinois
CoI: Robert Gruendl, University of Illinois
CoI: Kate Y. L. Su, University of Arizona
Title: High-Dispersion Spectroscopic Investigation of Hot WDs and CSPNs with IR Excesses
Abstract: White dwarfs (WDs) allow us to take a last glimpse of extrasolar planetary systems at their final evolutionary stage. No planets around WDs have been detected directly; however, two types of debris disks associated with subplanetary objects have been detected: (1) small dust disks around cool WDs replenished by tidally disrupted asteroids, and (2) large dust disks around hot WDs generated by collisions among Kuiper- Belt-like objects (KBOs). \vspace-0.15 cm To search for the latter dust disks, we made a Spitzer MIPS 24 (micron) survey of 72 hot WDs and found IR excesses for 7, all of which are central stars of planetary nebulae (CSPNs). We have also searched Spitzer's archive and identified 5 additional CSPNs with near- to mid-IR excesses. The spectral energy distribution of some IR excesses resemble those of post-AGB binaries, raising the suspicion that some of the IR excesses we have detected may not originate from KBO collisions. \vspace-0.15 cm We request high-dispersion spectroscopic observations of CSPNs with IR excesses in order to analyze the physical properties of the CSPNs and their circumstellar material to determine the origin of the dust disk. Specifically, we search for unresolved nebular line emission and double-peaked line profiles indicative of rotating gas disks, variations in the stellar H(alpha) line indicating companions, and anomalous metal abundances in CSPN photosphere.
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