Lowell Observatory astronomer lists life of giant stars in new study | Local

Astronomers have a new understanding of nearly 200 giant stars thanks to a new study from Lowell Observatory.

The study, led by Lowell astronomer Gerard van Belle, presents the precise sizes and temperatures of 191 giant stars.

Although this type of study has been done before, none come close in terms of scale or precision. It is considered the largest catalog of its kind ever published.

“At best, all other studies are only half that size in terms of star counts,” van Belle said.

A giant star is a type of star that is much larger and brighter than others of similar temperatures. According to van Belle, it is difficult to determine the size of a star, even with a modern telescope.

The special technology used in this project, however, has improved the strength of the telescope, making the once impossible task of obtaining the measurements possible.

“It’s the equivalent of looking at an orange in New York in Flagstaff and seeing the Sunkist sticker on that orange,” van Belle said.

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A team of astronomers and van Belle began making these high-precision measurements using California’s Palomar testbed interferometer in 1997, collecting data there until the facility was shut down. installation in 2008. After joining Lowell in 2011, he continued his work with the help of professionals and professionals. amateur astronomers across the country. Her father, a statistician, also got involved.






Lowell Observatory astronomer Gerard van Belle stands atop one of the arms of the Y-shaped Navy Optical Precision Interferometer on Anderson Mesa in 2018. Van Belle conducted a new study showcasing the precise sizes and temperatures of 191 giant stars.


Jake Bacon, Arizona Daily Sun file


He determined the measurement of hundreds of giant stars, including radius and temperature, during his research. This information helps astronomers better understand the lifespan of stars and how energy moves. It also gives a boost to researchers in other fields. For example, knowing the size of a star can help astronomers better infer the size of surrounding planets.

“One of the best ways to understand this better is to study more stars,” he said. “If we study more than one star, we get a better picture of how the internals work, including the sun.”

The study also provides an answer long sought after by researchers: what will happen to the sun? By studying other mature stars, van Belle determined that the sun will likely transform into a giant star in about 5 billion years, when it will then swell to 10 to 100 times its current size. The Earth will inevitably be swallowed up, as a result.

He reassured that fate is still far away.

“The sun will be as constant as it has been since the day you were born and throughout your life,” he added.

NASA’s James Webb Space Telescope, slated for launch next week, could usher in a new era in astronomy as it gathers information about the early stages of the universe and whether the planets beyond our solar system can live. Lisa Bernhard produced this report.



The research project, supported by NASA and the National Science Foundation, is intrinsic to the Lowell Observatory.

“It’s very much in Lowell’s blood,” he said. “It’s very difficult to do this work elsewhere – we have our own telescopes and control the weather. We have it in our DNA to support long-term projects.

The study, titled “Direct Measurements of Effective Temperatures and Linear Radii of Giant Stars: Calibration Against Spectral Types and V?k Color,” was published in The Astrophysical Journal.

Journalist Bree Burkitt can be reached at bburkitt@azdailysun.com or on Twitter at @breeburkitt.