Limits on Unresolved Planetary Companions to White Dwarf Remnants of 14 Intermediate-Mass Stars

TL;DR

This study uses Spitzer IRAC data to search for planetary companions around white dwarf remnants of intermediate-mass stars, setting upper mass limits and ruling out the presence of certain planetary companions.

Contribution

It provides new constraints on planetary companions around white dwarfs of intermediate-mass progenitors using mid-infrared observations and models.

Findings

No mid-infrared excess detected around targets.

Planetary companions down to 5-10 M_J are ruled out for most targets.

Combined data exclude d710 M_J companions around 40 white dwarfs.

Abstract

We present Spitzer IRAC photometry of white dwarf remnants of 14 stars with M = 3-5 Msol. We do not detect mid-infrared excess around any of our targets. By demanding a 3 sigma photometric excess at 4.5 micron for unresolved companions, we rule out planetary mass companions down to 5, 7, or 10 M_J for 13 of our targets based on the Burrows et al. (2003) substellar cooling models. Combined with previous IRAC observations of white dwarf remnants of intermediate-mass stars, we rule out \geq 10 M_J companions around 40 white dwarfs and \geq 5 M_J companions around 10 white dwarfs.