Sirius B Imaged in the Mid-Infrared: No Evidence for a Remnant Planetary System

TL;DR

This study used deep mid-infrared imaging to investigate Sirius B for debris disks, finding no evidence of a dusty planetary system, thus challenging previous claims of an infrared excess.

Contribution

The paper provides the first high-sensitivity mid-infrared observations of Sirius B, setting strict limits on the presence of a debris disk around it.

Findings

No significant infrared excess detected around Sirius B

Constraints placed on the size of any potential debris disk (<10%)

Supports the idea that Sirius B lacks a remnant planetary system

Abstract

Evidence is building that remnants of solar systems might orbit a large percentage of white dwarfs, as the polluted atmospheres of DAZ and DBZ white dwarfs indicate the very recent accretion of metal-rich material. (Zuckerman et al. 2010). Some of these polluted white dwarfs are found to have large mid-infrared excesses from close-in debris disks that are thought to be reservoirs for the metal accretion. These systems are coined DAZd white dwarfs (von Hippel et al. 2007). Here we investigate the claims of Bonnet-Bidaud & Pantin (2008) that Sirius B, the nearest white dwarf to the Sun, might have an infrared excess from a dusty debris disk. Sirius B's companion, Sirius A is commonly observed as a mid-infrared photometric standard in the Southern hemisphere. We combine several years of Gemini/T-ReCS photometric standard observations to produce deep mid-infrared imaging in five ~10 micron filters (broad N + 4 narrowband), which reveal the presence of Sirius B. Our photometry is consistent with the expected photospheric emission such that we constrain any mid-infrared excess to <10% of the photosphere. Thus we conclude that Sirius B does not have a large dusty disk, as seen in DAZd white dwarfs.