An unidentified space object was observed "screaming" out of our galaxy at a speed of more than one million miles per hour.

Although our Sun appears to be the center of the universe, it is actually moving at a speed of around 500,000 miles per hour as it circles the Milky Way galaxy. That's quick, but it pales in comparison to a star runaway that was just found and is speeding across space.

This stellar speedster, CWISE J124909+362116.0 (J1249+36 for short), is a low-mass star, or L subdwarf, with hypervelocity and possibly on a path to completely exit the Milky Way.

Stars on the run

A star travelling through space at an exceptionally rapid speed—typically more than 30 km/s—is known as a runaway star.

Due to supernova explosions or gravitational interactions, these stars are expelled from their original location, which is usually a star cluster. Close contacts with other big stars might cause a star to fall out of its cluster due to gravitational interactions.

On the other hand, if one of the stars in a binary system explodes as a supernova, the remaining star might be driven away quickly. Runaway stars have the ability to travel great distances and occasionally depart from their galaxies.

Their fast speeds and trajectories can reveal information about the dynamics and historical occurrences of their home regions. Astronomers can better understand star formation, stellar evolution, and the gravitational forces within star clusters by studying runaway stars.

Additionally, as they pass through the interstellar medium, they may produce shock waves that impact the nearby gas and dust.

J124909 and citizen science

The success of citizen science is demonstrated by the finding of J1249+36. Volunteers working on the Backyard Worlds: Planet 9 project—a public-scientist collaboration—were the first to notice it.

These citizen scientists search for moving objects in the sky by sorting through enormous volumes of data gathered by NASA's Wide-field Infrared Survey Explorer (WISE) program.

The ability of the human eye to recognise patterns makes it a priceless tool for identifying abnormalities that computer algorithms could overlook.

J1249+36, the runaway star

Volunteers were drawn to J1249+36 because of its exceptional speed. It was once estimated to be travelling at an astounding 1.3 million miles per hour—fast enough to escape the gravitational pull of the Milky Way.

Astronomers went to the W.M. Keck Observatory in Hawaii to examine the star's light using its powerful instruments in order to learn more about this fast-moving star. The results showed that the runaway star J1249+36 is a L subdwarf, which are small, cold stars that are among the oldest in our galaxy.

What is the origin story?

What gave this star such a huge kick was the question that most fascinated scientists. Two prominent theories surfaced. J1249+36 may have originally been a member of a binary star system that included a white dwarf, which is the dense residue of a dead star.

J1249+36 might have been launched into space at a high speed by a supernova explosion if the white dwarf had syphoned off too much material from its partner.

A close encounter with a black hole is the subject of the second theory. Black holes are believed to be located at the centers of globular clusters, which are dense swarms of stars.

The gravitational turmoil may have thrown J1249+36 from the cluster at a tremendous speed if it had ventured too close to a black hole binary (two black holes orbiting each other).

"This is where the source became very interesting, as its speed and trajectory showed that it was moving fast enough to potentially escape the Milky Way," said Adam Burgasser, the project's principal investigator and professor of astronomy and astrophysics at the University of California, San Diego.

The runaway star's chemical fingerprint

Scientists are searching for hints in the chemical makeup of the runaway star to ascertain which scenario is more likely. Heavy elements produced during the explosion may be present in J1249+36's atmosphere if it was launched by a supernova. On the other hand, the star's chemical composition may indicate if it came from a globular cluster.

Roman Gerasimov, a UC San Diego alumnus who created new models to investigate L subdwarfs, stated, "We're essentially looking for a chemical fingerprint that would pinpoint what system this star is from."

The wonders of the Milky Way

The finding of J1249+36 provides important insights into the history and dynamics of the Milky Way, regardless of whether its amazing trip was caused by a supernova, a close encounter with a black hole, or some other cosmic event. This rogue star serves as a reminder of the size and complexity of our universe as it races across space at unfathomable speeds.

The study of J1249+36 was presented at the American Astronomical Society's (AAS) 244th national meeting in Madison, Wisconsin.

This ongoing project is a wonderful illustration of how teamwork can result in amazing discoveries, thanks to the combined efforts of professional astronomers and citizen scientists. Who knows what further celestial surprises lie ahead of us in the vast Milky Way as we continue to explore the cosmos?