A study led by the astronomy consortium known as the Whole Earth Telescope showed a pulsating white dwarf called the “Diamond Star” may truly be crystalline.

Whole Earth Telescope is a collaboration of about 50 astronomers globally headquartered at Iowa State.

“Proving the core is crystalline is a breakthrough,” said Steven Kawaler, director of Whole Earth Telescope and professor of physics and astronomy. “It proves the fundamental predictions of physics.”

Kawaler said the new findings show astronomical science is moving in the right direction. Understanding the makeup of the pulsating, massive white dwarf “Diamond Star” helps measure the history of the galaxy and its longevity, he said. This is because once a white dwarf becomes crystalline, it lives forever, he said.

The star is called BPM37093, and being able to learn what’s inside it helps to support the theory that stars can be mostly crystalline, Kawaler said.

BPM37093 is called the “Diamond Star” because of its large carbon makeup. The molecules are stuck together in a state of repulsion rather than attraction, which means that a clump taken from the core will come apart.

“It is a diamond in the fictional sense,” Kawaler said.

The “Diamond Star” is the only pulsating and massive white dwarf known at this time. It is also the largest white dwarf known to astronomers.

The estimated mass of the “Diamond Star” is 10 raised to the 33rd power carats. The star measures 2,500 miles across.

White dwarfs are remnants of cooling stars, like Earth’s sun, and are measured in solar mass. One solar mass is equal to the mass of our sun, and the “Diamond Star” measured a little above one solar mass, Kawaler said.

The Whole Earth Telescope, which is headquartered at Iowa State and partially funded by the National Science Foundation, is a collaboration of telescopes around the world that can keep a 24-hour watch on a single target for an extended period of time. Whole Earth Telescope astronomers have been studying BPM37093 since 1998.

The researchers became involved with the study of the star when scientist Antonio Kanaan and others who were studying the star made a proposal to use the Whole Earth Telescope. They also requested time with the Hubble Telescope.

Kanaan discovered the pulsating, massive white dwarf in 1992 as a doctoral student at the University of Texas.

The telescopes observed the star for approximately two weeks in April of 1998 and 1999.

Kanaan and others were looking at the feasibility of using a form of seismology called asteroseismology to study the star. The astronomers wondered if the method would work if the core was crystalline.

Seismology is used to measure the vibrations of the star, which helps to show what is inside the star.

This is the only way to predict what is inside the star because you cannot see into it, Kawaler said.

“Pulsating, massive white dwarfs are rare,” Kawaler said. “The opportunity to study one is exciting.”