The chemical composition of a wierd star present in the halo of our Milky Way galaxy represents the primary evidence of the violent deaths of the universe’s first stars, a brand new study reports.
The universe’s first stars were born around 100 million to 250 million years after the Big Bang, which occurred about 13.8 billion years ago. But scientists are still at the hours of darkness about how the mass of this primary generation of stars was distributed.
Modeling of stars within the early universe indicates that a few of these stellar bodies can have had masses reminiscent of a whole lot of suns. Massive stars end their lives with gigantic cosmic explosions called supernovae, but stars with masses between 140 and 260 times that of the sun back then would have ended their lives in supernova blasts different from those typically seen within the later universe (referred to as Type II and Type Ia supernovae) , study team members said. These unique explosions are known as pair-instability supernovae (PISNe).
All supernovae spread elements heavier than hydrogen and helium, which astronomers call metals, throughout the universe. Metals are synthesized within the cores of giant stars and are incorporated into the subsequent generation of stellar bodies.
As they’re quite different from odd explosive stellar death throes, these PISNe should leave behind a novel chemical fingerprint in the subsequent generation of stars. Yet, until now, astronomers have didn’t discover these cosmic fingerprints.
In the brand new research, a team of scientists found that the chemically peculiar star LAMOST J1010+2358 could represent the primary evidence of PISNe from early massive stars.
The researchers used data collected by the Large Sky Area Multi-Object Fiber Spectroscopic Telescope (LAMOST) survey and follow-up observations by the Subaru Telescope in Hawaii to find out that LAMOST J1010+2358 formed in a gas cloud that was dominated by the stays of a 260-solar-mass star that died in a PISNe blast.
Probably the most significant chemical evidence marshaled by the team was a particularly low abundance of sodium and cobalt, and a big variance between elements which have odd and even numbers of electrons.
This is critical, because PISNe occur as a consequence of an instability brought on by the production of electron and anti-electron — or positron — pairs. This instability reduces thermal pressure contained in the core of a really massive star and results in a partial collapse.
“It provides a vital clue to constraining the initial mass function within the early universe,” study corresponding creator Zhao Gang, a professor on the National Astronomical Observatories of the Chinese Academy of Sciences (NAOC), said in a press release. “Before this study, no evidence of supernovae from such massive stars has been present in the metal-poor stars.”
Moreover, the team found that LAMOST J1010+2358 is way richer in iron than other metal-poor stars of the same age within the galactic halo. This means that second-generation stars forged in clouds containing the gaseous stays of PISNe could possibly be more abundant in heavy elements than currently thought.
“One in every of the holy grails of trying to find metal-poor stars is to search out evidence for these early pair-instability supernovae,” astrophysicist Avi Loeb, the previous chair of the Astronomy Department at Harvard University, who was not involved within the research, said in the identical statement.
The team’s research is detailed in a paper published online today (June 7) within the journal Nature.