Ramanujan Auditorium

The Nearby Evolved Stars Survey

Sundar Srinivasan

National Autonomous University of Mexico

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;
evolvedstars.space). 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 summarise the aims of the survey and mention some preliminary results
and advertise ongoing research. The team welcomes Indian scientists to ensure continued access to the JCMT and to add other complementary
facilities such as the GMRT to our list.