Spectral Analysis of Mid-IR Excesses of White Dwarfs

TL;DR

This study investigates mid-infrared excesses around white dwarfs and pre-white dwarfs using spectroscopic data to understand the nature of circumstellar dust potentially originating from sub-planetary objects.

Contribution

It provides a detailed spectroscopic analysis of IR excesses in white dwarfs and pre-white dwarfs, offering insights into their circumstellar environments and potential planetary debris.

Findings

Detection of mid-IR excesses indicating circumstellar dust.

Spectroscopic evidence supporting the presence of sub-planetary debris.

Enhanced understanding of dust origins around evolved stars.

Abstract

In our Spitzer 24 \mu m survey of hot white dwarfs (WDs) and archival Spitzer study of pre-WDs, i.e., central stars of planetary nebulae (CSPNs), we found mid-IR excesses for -15 WDs/pre-WDs. These mid-IR excesses are indicative of the presence of circumstellar dust that could be produced by 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 paper we present the analysis of these spectroscopic observations and discuss the nature of these IR excesses.