Observational identification of a sample of likely recent common-envelope events
Journal article, 2022

One of the most poorly understood stellar evolutionary paths is that of binary systems undergoing common-envelope evolution, when the envelope of a giant star engulfs the orbit of a companion. The interaction that ensues leads to a great variety of astrophysical systems and associated phenomena, but happens over a very short timescale. Unfortunately, direct empirical studies of this momentous and complex phase are difficult at present because few objects experiencing, or having just experienced, common-envelope evolution are known. Here we present Atacama Large Millimeter/submillimeter Array observations of minor CO isotopologues towards a sample of sources known as water fountains, which reveal that almost all of them recently lost a substantial fraction of their initial mass over a timescale of less than a few tens to a few hundreds of years. The only known mechanism able to explain such rapid mass ejection, corresponding to a large fraction of the stellar mass, is the common-envelope evolution. A stellar population analysis shows that the number of water-fountain sources in the Milky Way is comparable to the expected number of common-envelope events that involve low-mass evolved stars. Thus, the known sample of water-fountain sources accounts for a large fraction of the systems undergoing a common-envelope phase in our Galaxy. As one of the distinguishing characteristics of water-fountain sources is their fast bipolar outflow, we conclude that outflows and jets play an important role right before, during or immediately after the common-envelope phase.


Theo Khouri

Chalmers, Space, Earth and Environment, Astronomy and Plasmaphysics

Wouter Vlemmings

Chalmers, Space, Earth and Environment, Astronomy and Plasmaphysics

Daniel Tafoya

Chalmers, Space, Earth and Environment, Onsala Space Observatory, Observation Support

A. F. Perez-Sanchez

Leiden University

C. S. Contreras

Centro de Astrobiologia (CAB)

J. F. Gomez

Institute of Astrophysics of Andalusia (IAA)

Hiroshi Imai

Kagoshima University

R. Sahai

Jet Propulsion Laboratory, California Institute of Technology

Nature Astronomy

23973366 (eISSN)

Vol. 6 2 275-286

Understanding the mass-loss process of evolved Sun-like stars using high-angular-resolution observations

Swedish Research Council (VR) (2019-03777), 2020-01-01 -- 2023-12-31.

Onsala rymdobservatorium infrastruktur

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

Subject Categories

Astronomy, Astrophysics and Cosmology


Geosciences, Multidisciplinary



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