Data collected by University of Toledo astronomers again is drawing national attention as they observed for the first time tiny crystals of a green mineral called olivine falling down on a new star.Dr. Tom Megeath, associate professor of astronomy, and his graduate student, Charles Poteet, observed the crystals in a collapsing cloud of gas and dust around a forming star.
“Astronomers see these materials throughout space, but most often it is dust and not in a crystal form,” Megeath said. “You need to have really hot temperatures to make these crystals, and in this case there is no heat source, so it’s not immediately clear where this happened.”
Astronomers hypothesize that the crystals formed when the materials were heated up near the surface of the star, but then were pushed out via a jet into the colder surrounding cloud where they cooled. The materials weren’t pushed out far enough and now are being pulled back into the star, Megeath said.
The observations were published in Astrophysical Journal Letters, and NASA publicized the findings, drawing attention from national news organizations, including Time and MSNBC.
The crystals were observed on the protostar HOPS-68 in the constellation Orion using the NASA Spitzer Space Telescope.
The crystals are in the form of forsterite and belong to the olivine family of silicate minerals, which is very common on Earth such as in periodot gemstones and the green sand beaches of Hawaii.
While forsterite crystals have been spotted before around young stars, it is surprising to observe them in the outer collapsing cloud of a protostar because of the colder temperatures there — about minus 280 degrees. That is why astronomers believe the jets are transporting the crystals to the outer cloud.
Such crystals also are found in comets and meteorites, which are very cold, and that is part of what makes the solar system such a mystery, Megeath said.
“You would expect to find crystals close to the sun and not in the cold outer reaches of our solar system, but that is not the case. It’s a real mystery,” Megeath said. “One solution to this mystery is that, when the sun and planets were forming, crystals were carried to the outer parts of the solar systems by jets, just like we see in the protostar HOPS-68.”
Megeath said this observation could help astronomers get a bigger picture of how the solar system formed and how these different types of materials have come to coexist.
“Our long-term goal is to understand the big picture of how stars and planets form, and we’re going to have a number of discoveries like this along the way,” he said. “Exactly how the discovery of crystals will fit into the big picture is not certain, but we are anxious to find out.”