The substellar neighborhood: a stunningly diverse population of brown dwarfs

Federico Marocco

California Institute of Technology

The census of the coldest constituents of the Solar Neighborhood remains incomplete. Completing such census is one of the driving goals for the CatWISE and "Backyard Worlds: Planet Nine" teams, who have discovered hundreds of new late-T and Y dwarfs using data from WISE/NEOWISE. In my talk I will present the results of our on-going observing campaign, which is revealing a stunning diversity among the substellar population, a diversity that atmospheric models suggest is driven by metallicity. Among the most intriguing objects discovered are: some of the lowest-mass, coldest substellar companions to main sequence stars; the coldest subdwarfs in the solar neighborhood, including possibly the first Y subdwarf in the local census (nicknamed "The Accident" because of its serendipitous discovery by a citizen scientist); and a cold Y dwarf showing methane emission in its NIR spectrum, which is a possible indication of auroral activity.

Date:	Thursday, 28 March 2024
Time:	12:30
Where:	Université de Montréal
	A-3521.1