Abstract

The last decade has seen the discovery of a growing population of planetary-mass companions (~<20 M_Jup; hereafter PMCs) 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. I will present new results from my automated pipeline to find wide-orbit companions of stars via point spread function (PSF) subtraction in Spitzer/IRAC images. A Markov Chain Monte Carlo algorithm is the backbone of this PSF subtraction routine that efficiently creates and subtracts χ2-minimizing instrumental PSFs, measuring infrared photometry of the systems across the four IRAC channels (3.6 μm, 4.5 μm, 5.8 μm, and 8 μm). I will present a re-analysis of archival Spitzer/IRAC images of 11 young, low-mass (44 M_Jup-0.88 M_Sun; K3.5-M7.5) stars in 3 nearby star-forming regions (Chameleon, Taurus, and Upper Scorpius; d ~ 150 pc; τ ∼1–10 Myr) known to host faint companions over a range of projected separations (1.7”-7.3”). I will discuss the characteristics of the systems found to have low-mass companions with non-zero [I1] − [I4] colors, including the confirmation of a ρ = 4.66” (540 AU), M = 20 M_Jup companion to [SCH06] J0359+2009, a young brown dwarf in Taurus.

My survey is sensitive to companions with masses approaching that of Jupiter at orbital radii of a few hundred AU, discovering wide PMCs in their birth environments and revealing their circum(sub)stellar disks. I will present my newest results in measuring the mid-IR photometry of substellar companions that have been directly imaged at optical or near-IR wavelengths and an automated companion search of all known young stars with existing Spitzer/IRAC data, concluding with my ongoing follow-up observations of candidate wide PMC systems with ground-based telescopes and the outlook for future observations with space-based telescopes.

Abstract

X-ray observations are indispensable for understanding the cosmos. Much of the baryonic matter and the sites for the most active energy releases in the Universe are primarily observable in X-rays.  Lynx is a revolutionary X-ray observatory with the power to transform our understanding of the cosmos through unprecedented X-ray vision into the otherwise invisible Universe.  It is one of the four NASA Strategic Mission concepts under consideration by the 2020 Decadal Survey.  Lynx is designed to pursue three fundamental science pillars: (1) seeing the dawn of black holes, (2) revealing what drives galaxy formation and evolution, and (3) unveiling the energetic side of stellar evolution and stellar ecosystems. For its spacecraft design and operational concept, Lynx leverages the overarching, proven architecture from Chandra. The Lynx payload provides extraordinary advances in science capabilities thanks to an extremely powerful combination of sub-arcsecond angular resolution and high throughput of its X-ray mirror, and the transformational spectroscopic capabilities of its science instruments. Strong heritage and substantial maturity in key new technologies lead to a credible cost for this Great Observatory-class mission.

Abstract

The tilt of a planet’s spin axis off its orbital axis (“obliquity”) is a basic physical characteristic that plays a central role in determining the planet’s atmospheric circulation, energy redistribution, and climate. Moreover, by strongly enhancing the tidal dissipation rate, planetary obliquities can shape not only the physical features of exoplanets, but also their orbital architectures. Large planetary obliquities can be generated by secular spin-orbit resonances. These occur when the rate of a planet’s spin axis precession matches the rate of its orbital precession. I will present evidence that close-in, compact, Kepler-type systems frequently experience this mechanism – a simple but fascinating result of their intrinsic physical and orbital properties. I will highlight the consequences of this obliquity-driven sculpting by linking it to several strange features of the observed planet population, including the mysterious overabundance of planets wide of mean-motion resonances and the remarkably rapid orbital inspiral of the highly inflated hot Jupiter, WASP-12b.

Abstract

My team and I recently completed building an Integral Field Spectrograph (IFS) optimized for exoplanet direct imaging.  The instrument, dubbed the Arizona Lenslets for Exoplanet Spectroscopy (ALES), builds upon the successes of an earlier prototype instrument built in 2015. ALES is uniquely powerful for exoplanet direct imaging because it is the only IFS operating in the thermal-IR where cool exoplanets peak in brightness. By probing the peak of exoplanet SEDs ALES provides the best constraints on exoplanet luminosities while simultaneously covering the fundamental transitions of both CH4 and CO.  Consequently, ALES also provides the most sensitive probes of the physical processes sculpting exoplanet carbon chemistry. I will present preliminary science results with ALES including observations of both directly imaged companions and a candidate companion discovered within a protoplanetary disk.  I will also discuss combining ALES with dual-aperture imaging mode at the 23 m LBT to increase spatial resolution and sensitivity.