ITC Colloquium - Daniella Bardalez Gagliuffi (AMNH) and Evan Bauer (CfA)


Thursday, November 5, 2020, 11:00am to 12:00pm



Daniella Bardalez Gagliuffi (AMNH)  "System architectures as fossils of brown dwarf and giant planet formation"

Brown dwarfs and giant planets share many similarities in their physical properties and atmospheric dynamics, but the most fundamental difference between these two types of objects is the formation pathway that led to their creation. The key to differentiating between formation pathways may lie in their chemical compositions. Recent discoveries have unveiled a number of systems with substellar companions in orbital configurations that are challenging to directly attribute to a formation mechanism. These extreme systems are key pieces to understand substellar formation and its subsequent evolution as a population.
In this talk, I will revisit extreme systems with brown dwarfs and giant planets in binary and multiple systems. By analyzing the orbital properties of these systems, we can explore the parameter spaces that each distinct population occupies and identify signatures of top-down or bottom-up formation. I will discuss future directions for a comprehensive characterization of the statistical distribution of substellar populations and the individual characterization of their abundances through atmospheric retrievals. 

Evan Bauer (CfA)  "Runaway Subdwarfs and White Dwarfs from Thermonuclear Supernovae" 

Thermonuclear supernovae in binary star systems leave remnants of their companions. These runaway companions have high velocities after being liberated from fast binary orbits, and they can also show signatures of composition from supernova ejecta. Compact binary systems containing hot subdwarf stars can produce runaways leaving the galaxy with velocities approaching 1000 km/s, and double white dwarf binaries can produced hypervelocity runaways as fast as 3000 km/s. Motivated by recent observations of two classes of runaway stars that appear to be associated with supernovae in binary systems, I will discuss ongoing theoretical work to understand the unusual structure and evolution of these stars and what they can tell us about the supernovae that produced them.

See also: Colloquium, 2020-21