Subtle and Spectacular: Diverse White Dwarf Debris Disks Revealed by JWST

TL;DR

This study reports 12 new detections of warm debris disks around white dwarfs using JWST, revealing diverse mineralogical features and providing insights into dust composition, origin, and ongoing collisional processes.

Contribution

It presents the first comprehensive spectroscopic survey of white dwarf debris disks with JWST, uncovering subtle and extreme features, and expanding mineralogical understanding of these disks.

Findings

Detection of the faintest infrared excesses around white dwarfs.

Identification of the strongest silicate emission features known.

Discovery of disks with featureless, high-temperature dust continuum.

Abstract

This letter reports 12 novel spectroscopic detections of warm circumstellar dust orbiting polluted white dwarfs using JWST MIRI. The disks span two orders of magnitude in fractional infrared brightness and more than double the number of white dwarf dust spectra available for mineralogical study. Among the highlights are: i) the two most subtle infrared excesses yet detected, ii) the strongest silicate emission features known for any debris disk orbiting any main-sequence or white dwarf star, iii) one disk with a thermal continuum but no silicate emission, and iv) three sources with likely spectral signatures of silica glass. The near ubiquity of solid-state emission requires small dust grains that are optically thin, and thus must be replenished on year-to-decade timescales by ongoing collisions. The disk exhibiting a featureless continuum can only be fit by dust temperatures in excess of 2000K, implying highly refractory material comprised of large particles, or non-silicate mineral species. If confirmed, the glassy silica orbiting three stars could be indicative of high-temperature processes and subsequent rapid cooling, such as occur in high-velocity impacts or vulcanism. These detections have been enabled by the unprecedented sensitivity of MIRI LRS spectroscopy and highlight the capability and potential for further observations in future cycles.