The Demographics of Wide Planetary-Mass and Substellar Companions and Their Circum(sub)stellar Disks through PSF Fitting of Spitzer/IRAC Archival Images

The last decade has seen the discovery of a growing population of planetary-mass and substellar companions (~<20 M_Jup) to young stars which are often still in the star-forming regions where they formed. These objects have been found at wide separations (>100 au) from their host stars, challenging existing models of both star and planet formation. Demographic trends with mass and separation should distinguish between these formation models.

The extensive Spitzer/IRAC data set of every major star-forming region and association within 300 pc has great potential to be mined for wide companions. In this poster I will present the latest developments of an automated pipeline I have developed to find wide-orbit PMCs of stars via PSF subtraction in Spitzer/IRAC images. An MCMC algorithm is the backbone of this PSF subtraction routine that efficiently creates and subtracts \(\chi\)²-minimizing instrumental PSFs, measuring the mid-infrared photometry of these systems. I will present a re-analysis of archival Spitzer/IRAC images of 20 stars (G0-M7.5) known to host companions (1.2”-12.3”), reporting new mid-IR photometric measurements of this sample of wide-orbit companion systems. I will also discuss my ongoing follow-up observations of wide planetary-mass/substellar companion systems with ground-based telescopes, and the outlook for future observations with space-based telescopes.