cropped-Hubble's Stunning View of Globular Cluster NGC 6652

How do you Weigh Stars? RR Lyrae Offer Clues

Much like seismology unveils Earth's interior, asteroseismology dives into a star's core using its pulsations.


Stars are the cosmic tapestry that make up our universe. But, how do you measure a star’s weight? RR Lyrae stars, a unique variety, have long presented this puzzle to astronomers. Now, a breakthrough sheds light on their mysterious masses.

RR Lyrae stars, older than our sun, have grown to be larger and brighter while utilizing helium as their primary fuel. These stars offer a lens into the evolution of the Milky Way. However, determining their mass remained an astronomical challenge.

Driven by an internal “stellar engine”, the kappa mechanism, these stars showcase rhythmic pulsations. Essentially, a layer within the star modulates energy emitted from its core, resulting in regular expansion and contraction of its outer layers. This expansion and contraction pattern, noticeable as periodic brightness changes, offers insights into the star’s inner world.

Decoding Asteroseismology

Much like seismology unveils Earth’s interior, asteroseismology dives into a star’s core using its pulsations. Historically, RR Lyrae stars appeared simple, showing limited pulsation patterns, making them unsuitable for asteroseismic study.


Recent sophisticated observations unveiled the complexity of RR Lyrae stars. These stars, contrary to prior belief, exhibit additional pulsations, albeit subtle. For years, the origins of these pulsations remained elusive. Yet, advancements proposed these are tied to specific non-radial pulsations, a game-changer for asteroseismology.

Pioneering Mass Determination

Drs. Henryka Netzel, László Molnár, and Meridith Joyce from the Konkoly Observatory in Budapest combined insights from top-tier space telescopes with cutting-edge stellar pulsation models. Their pursuit? Verify theories surrounding the RR Lyrae stars’ pulsations.

The results, showcased in the Monthly Notices of the Royal Astronomical Society, indicate these stars’ pulsations align with the proposed non-radial modes. The research successfully discerned the stars’ masses, aligning with existing stellar evolution models.


The team is now eager to further this research. Their goal is to harness this newfound method to discern the masses of various RR Lyrae pulsators, comparing them across different stellar life stages.

PLEASE READ: Have something to add? Visit Curiosmos on Facebook. Join the discussion in our mobile Telegram group. Also, follow us on Google News. Interesting in history, mysteries, and more? Visit Ancient Library’s Telegram group and become part of an exclusive group.

Written by Justin Gurkinic

Hey, my name is Justin, and my friends call me Gurk. Why? Becuase of my last name. It sounds like a vegetable. Kind of. I love sleeping and writing. History is my thing.

Write for us

We’re always looking for new guest authors and we welcome individual bloggers to contribute high-quality guest posts.

Get In Touch