DEATHSTAR—CO Envelope Size and Asymmetry of Nearby AGB Stars
Journal article, 2022

Low-and intermediate-mass stars evolve into asymptotic giant branch (AGB) stars near the end of their lives, losing mass through slow and massive winds. The ejected material creates a chemically-rich expanding envelope around the star, namely the circumstellar envelope (CSE). Investigating the anisotropy of the mass-loss phenomenon on the AGB is crucial in gaining a better understanding of the shaping of the CSE during the transition from AGB star to planetary nebula (PN). We investigate possible signs of deviation from spherical symmetry in the CO-emitting CSEs of 70 AGB stars by analysing their emission maps in CO J = 2 − 1 and 3 − 2 observed with the Atacama Compact Array, as part of the DEATHSTAR project. We find that about one third of the sources are likely aspherical, as they exhibit large-scale asymmetries that are unlikely to have been created by a smooth wind. Further high-resolution observations would be necessary to investigate the nature of, and the physical processes behind, these asymmetrical structures.

Mass loss

Circumstellar matter


AGB stars


M. Andriantsaralaza

Uppsala University

Wouter Vlemmings

Chalmers, Space, Earth and Environment, Astronomy and Plasmaphysics

S. Ramstedt

Uppsala University

Elvire De Beck

Chalmers, Space, Earth and Environment, Astronomy and Plasmaphysics


20754434 (eISSN)

Vol. 10 1 33

Onsala space observatory infrastructure

Swedish Research Council (VR) (2017-00648), 2018-01-01 -- 2021-12-31.

RadioNet 4

European Commission (EC) (EC/H2020/730562), 2017-01-01 -- 2020-12-31.

Subject Categories

Subatomic Physics

Meteorology and Atmospheric Sciences

Astronomy, Astrophysics and Cosmology



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