Searching for Wide Planetary-Mass and Substellar Companions with Circum(sub)stellar Disks through PSF-Fitting of Spitzer/IRAC Archival Images

Raquel Martinez (UT Austin)
Friday, October 30, 2020 - 2:00pm to 3:00pm

The last decade has seen the discovery of a growing population of planetary-mass and substellar companions (~<20 MJup) 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 to stars. In this presentation, I will describe my development of an automated pipeline to leverage this archive and find wide-orbit companions of stars via point spread function (PSF) subtraction in Spitzer/IRAC images. My survey is sensitive to companions with masses approaching that of Jupiter at orbital radii of a few hundred AU, discovering wide companions in their birth environments and revealing their circum(sub)stellar disks. I will present a re-analysis of archival Spitzer/IRAC images of 20 stars (G0-M7.5) known to host faint planetary-mass and substellar companions (1”-12”) through previous high-contrast imaging observations at optical or near-IR wavelengths. I will report new mid-IR photometric measurements of this sample of wide-orbit companion systems, then discuss an automated companion search of all known young stars with existing Spitzer/IRAC data, concluding with my ongoing follow-up observations of candidate wide planetary-mass/substellar companion systems with ground-based telescopes and the outlook for future observations with space-based telescopes.

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