Oxygen Vanishes From Three Dozen Dwarf Galaxies; Astronomers Open Cosmic Cold Case

BALTIMORE, MD. — Astronomers using NASA's Hubble Space Telescope report that something appears to be missing from more than three dozen nearby dwarf galaxies: oxygen, and a great deal of it. According to The Debrief, the findings were published in The Astrophysical Journal.

The inquiry was carried out under the Galaxies Losing Oxygen via Winds project, known as GLOW. Investigators combined Hubble observations with archived data from the retired Spitzer Space Telescope and recent readings from ground-based radio telescopes. With these, they reconstructed the star-formation history of each galaxy, estimated how much oxygen its stars ought to have produced, and compared the sum with the amount now detectable.

The books, so to speak, did not balance. University of Utah astrophysicist O. Grace Telford, a co-author, reasoned that the oxygen had to have been inside the galaxies at some point, and so it "must have been ejected." The leading suspects are powerful stellar winds and supernova explosions, which the study suggests may strip away oxygen far more efficiently than current models anticipated.

The whereabouts of the missing element remain undetermined. Astronomers suspect much of it was expelled into surrounding space, but present data cannot say where it went. The dwarf galaxies, the report states, appear to retain only a small fraction of what their stars make, which could force revisions to models of how galaxies distribute heavy elements.

Kristen W. McQuinn, a co-author and the GLOW principal investigator, noted that tracing oxygen helps explain galaxy evolution and how galaxies enrich the intergalactic medium. Further observations by Hubble, the James Webb Space Telescope and the Nancy Grace Roman Space Telescope may, the report says, help settle where the oxygen has gone.