🌟 This aging star pulses faster and faster: what should we expect?

At the heart of the Leo constellation, the star R Leonis pulses like a slowly beating heart. This red giant has captivated astronomers for more than two centuries due to its regular changes in brightness.

R Leonis belongs to the category of Mira-type variable stars. These stars at the end of their lives periodically expand and contract, which changes their brightness. Both amateur and professional astronomers can thus observe its metamorphoses with a certain consistency, making it a privileged subject of study.


A recent analysis of data spanning 200 years has shown that the pulsation rate of R Leonis is accelerating. The time between its brightest (or faintest) phases, which lasts several months, has decreased by about three days since the beginning of the 19th century. For a star with usually stable behavior, this evolution represents a notable change in its internal dynamics.

Researchers have also detected long-term modulations in these pulsations. Cycles of about 35 and 98 years superimpose their effects, creating a pattern. These observations indicate that the star has several internal rhythms interacting with each other, as if several metronomes were beating at the same time.

The dust emitted by R Leonis also plays a role. The shells of matter surrounding it evolve over time, influencing how its light reaches us.

These discoveries are based on historical observations. Although the archives of the American Association of Variable Star Observers offer valuable hindsight, modern methods allow for more precise measurements. These results, however, require cautious interpretation, as observation techniques have evolved over time.

R Leonis thus offers us a unique glimpse of stellar evolution in real time. As observations will provide new data in the coming years, astronomers will be able to determine whether this acceleration is permanent or temporary.