Astronomers have discovered that the stars in our galaxy have actually traveled distances, however long that may have taken in cosmic time.
From where we see them, stars seem to just stay put, emitting light from up in the heavens. Like planets, stars actually have orbits that can also dramatically change.
Researchers at the New Mexico State University (NMSU) collaborated with the Sloan Digital Sky Survey (SDSS) to create a map of the Milky Way that revealed about 30 percent of our galaxy's stars whose orbits have dramatically changed.
Michael Hayden, an NMSU astronomy graduate student and the study's lead author, mentioned how people can travel even halfway around the world, away from their birthplaces. "Now we are finding the same is true of stars in our galaxy," he said.
In the study, the researchers used the SDSS Apache Point Observatory Galactic Evolution Explorer (APOGEE) spectrograph to draw out a new map of the galaxy. They were able to look at around 100,000 stars and observe them for a four-year period.
By measuring the elements in each star's atmosphere, the team was able to interpret the newly drawn-out map of the Milky Way. Hayden explained that the life history and ancestry of a star can be determined by studying its chemical composition.
Detailed spectra provide chemical information on the stars, including the amount of light emitted at varying wavelengths. Specific elements and compounds are represented by prominent lines, which astronomers can read to determine what a star is made up of.
According to astronomy professor Jon Holtzman, who was also involved in the study, star spectra are proof of the constant change occurring in our galaxy. He explained that stars have heavier elements within their cores. When a star dies, those elements are transformed into gas, which later make up new stars.
The amount of heavy elements in a star can help astronomers trace where the star was born. A newer generation of stars is then most likely to have heavier elements than the previous generation.
The formaton of stars, of course, vary from one region in the galaxy to another; some are more vigorous than others.
Looking at the detailed pattern of abundant elements in their study, the team discovered that the data could be explained by a model where stars migrate radially. Stars can either move into or away from the center of the Milky Way, due to irregularities like the galaxy's spiral arms.
Stars near the Earth's sun have previously shown evidence of migration patterns. The NMSU, however, boasts discovering the first evidence that stellar migrations occur all throughout the galaxy.
The research is further explained in an article published in The Astrophysical Journal.
