One of the surprising discoveries coming out of Gaia data release 3, is that Gaia is able to detect starquakes – tiny motions on the surface of a star – that change the shapes of stars, something the observatory was not originally built for.

Previously, Gaia already found radial oscillations that cause stars to swell and shrink periodically, while keeping their spherical shape. But Gaia has now also spotted other vibrations that are more like large-scale tsunamis. These nonradial oscillations change the global shape of a star and are therefore harder to detect.

Nonradial oscillation modes cause a star's surface to move while it rotates, as shown in the animation. Dark patches are slightly cooler than bright patches, giving rise to periodic changes in the brightness of the star. The frequency of the rotating and pulsating stars was increased 8.6 million times to shift them into the audible range of humans.

Acknowledgement: Animation and sonification were created by: Dr. Joey Mombarg, KU Leuven, Belgium. Based on information from Gaia Data Release 3: Pulsations in main-sequence OBAF stars as observed by Gaia by the Gaia Collaboration, De Ridder et al., 2022, submitted to A&A. Van Reeth et al. 2015, ApJS 218, id.2, 32 pp. Mombarg et al. 2021, A&A 650, id.A58, 23 pp.

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