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New catalog of stars stirs up science mystery

A dense cluster of brightly colored red, blue, and gold stars
NASA/ESA/T.Brown(STScl)
Stars in the heart of the Milky Way imaged by the Hubble Space Telescope

Anew study from Flagstaff’s Lowell Observatory describes nearly two hundred giant stars, the largest catalog of its kind ever published. KNAU’s Melissa Sevigny reports, the research has stirred up new questions about the universe.

The catalog records the temperatures and sizes of giant stars which are nearing the end of their lifespans. Lead author Gerard van Belle says the work began more than two decades ago.

He says, "This means you have a lot of data to really, really, finally, pin down the relationships between the brightness of the star and its temperature, the color of a star and its temperature, the color of a star and its radius, and you start to tease out little details as well."

One unexpected finding was that the continuum of stars from hot blue ones to cool red ones has a gap. Stars of a certain color and temperature are missing. Van Belle speculates it’s related to the physics of how matter forms inside stars.

"These sorts of details can be interesting to find, because then you try to chase down and do the Sherlock Holmes work, on trying to figure out: what is it that’s causing that?" van Belle says. "Because this is very odd."

Other applications for the research include calculating the sizes of planets that orbit distant stars, and predicting how our own Sun will behave as it grows older.

Melissa joined KNAU's team in 2015 to report on science, health, and the environment. Her work has appeared nationally on NPR and been featured on Science Friday. She grew up in Tucson, Arizona, where she fell in love with the ecology and geology of the Sonoran desert.