Abstract

The Drop during Less than 300 days of a Dusty White Dwarf's Infrared Luminosity

Siyi Xu (University of California, Los Angeles)

Mike Jura (UCLA)

Some white dwarfs display excess infrared radiation from a disk produced by tidally disrupted asteroids. Here, we report both new Spitzer/IRAC and broadband JHK band photometries for a dusty white dwarf. We find that the fluxes longward of 3 micron decreased significantly within 300 days during 2010 and possibly also the K band flux. The drop in the infrared luminosity can either be due to an increase of inner disk radius, an increase of disk inclination or a combination of both. We discuss three hypothesis: (i) a recent planetesimal disruption event; (ii) instability in the circumstellar disk; (iii) perturbation from an unseen planet. The current situation is tantalizing; high sensitivity, high cadence infrared studies will be a new tool to study the interplay between the disk and the host white dwarf stars.

Mode of presentation: oral