Caltech theoretical astrophysicist Jim Fuller's model proposes that a red giant receives roughly 10,000 tiny kicks over several hundred thousand years as blobs of gas leave its surface unevenly and push the star in the opposite direction, with each modeled push amounting to only a few meters per second. [1]

Because the kicks point in random directions, they do not add as a straight acceleration; the model treats them as a random walk whose net effect could approach one kilometer per second by the time the dense core becomes a white dwarf, making accumulation rather than any single eruption its central mechanism. [1]

That speed might help explain earlier observations showing that widely separated stellar pairs are less common after one member becomes a white dwarf, because a gentle accumulated push could unbind a loosely held binary, though those observations motivate rather than directly reveal the proposed kicks.

The proposal also predicts that some altered orbits could end in collisions, but no new kick, collision or stellar population was observed in this work, and the manuscript was presented at an American Astronomical Society meeting and submitted rather than reported as peer reviewed. [1]

The explanation is elegant precisely because it is testable; until observations distinguish it from alternatives and establish rates, however, 10,000 kicks, one kilometer per second and occasional collisions remain outputs of a model, not events astronomers have directly counted.

-- KENJI NAKAMURA, Tokyo