The cool brown dwarf objects span the gap between stars with hotter temperatures and gas giant planets with much cooler temperatures. Scientists study these brown dwarf objects to understand how both planets and stars formed. The T dwarfs, a subset of the brown dwarfs, are the coolest well-populated group of these objects. Thus, they could be good analogs for the cool atmospheres of large exoplanets. However, we do not understand their atmospheric properties. The investigators will study those cooler substellar objects including T dwarfs and companions having planetary masses, and in-between transition objects. They will learn about the atmospheres, gravity, dust and cloud properties of these objects, and use this information to develop models to describe the properties of these substellar objects. This research serves the national interest by increasing our knowledge of these objects that are transitional between planets and stars, contributing to our understanding of planet formation. Undergraduate students from the CUNY colleges will work on this research. Public outreach events as different as the Astronomy on Tap program and Hayden Planetarium presentations will reach a diverse public audience.
Brown dwarf objects, of which T dwarfs are the coolest well-populated spectral class, are promising analogs for the cool atmospheres of exoplanets, but the diversity of their atmospheric properties is not yet well understood. The principal investigators and team will conduct a comprehensive study of cool, substellar objects, including L-T transition objects, T dwarfs, Y dwarfs, and planetary-mass companions. The team will derive the physical and atmospheric properties; identify and calibrate spectral diagnostics of secondary parameters like gravity, metallicity, and dust/cloud properties of these substellar objects; and provide detailed feedback from model fits; thus establishing a foundation for exoplanet atmosphere studies. The team has the data and analysis tools in hand to curate benchmark objects, generate template spectra, and identify spectral outliers; create spectral energy distributions; calculate bolometric luminosities; fit synthetic spectra from atmospheric models to low, medium, and high resolution spectra; constrain age, radius, and mass using kinematics and evolutionary models; and curate a public compilation of benchmark and outlier objects. The principal investigators are experts in empirical analysis of brown dwarf spectra, photometric and kinematic analysis of brown dwarfs, and analysis with synthetic spectra from cool model atmospheres. Undergraduate students from the student population of the CUNY colleges will be incorporated in projects related to this research. Public outreach events such as the Astronomy on Tap program, STARtorial science fashion blog, Hayden Planetarium presentations, and the AstroBetter website, will reach and interact with a diverse public audience.
