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Astro Seminar

The Nearby Evolved Stars Survey: description and initial results

Speaker: Sundar Srinivasan (UNAM)
Date: Thursday 10 February 2022
Time: 16:00
Venue: Zoom

Asymptotic giant branch (AGB) stars drive the chemical evolution of galaxies — the gas and dust ejected in slow winds from these objects seeds the formation of the next generation of stars. Over the past two decades, advanced space-based infrared facilities have allowed us to identify and characterise the properties of AGB stars in galaxies in the Local Group. Studies of Galactic AGB stars, however, are impeded by the foreground extinction and confusion in the Galactic Plane, which complicate the distance estimation. The recent availability of Gaia parallaxes for the nearest evolved stars has somewhat alleviated this problem. By augmenting these data with a new method of distance estimation, we identify a sample of ~850 nearby (<3 kpc) evolved-star candidates. This volume-complete sample is studied as part of the Nearby Evolved Stars Survey (NESS). The NESS data consist of observations of the CO J = (2-1) and (3-2) rotational emission as well as sub-millimetre continuum using the James Clerk Maxwell Telescope (JCMT) and Atacama Pathfinder EXperiment (APEX), with data at other wavelengths from facilities such as the Nobeyama Radio Observatory (NRO). In this talk, I will describe the NESS program and discuss some early results from the survey.