According to a recent research, the chemical signatures of the star are
proof that the earliest big stars produced pair-instability
supernovae.
According to a recent research, the odd star's chemical makeup in the Milky
Way galaxy's halo provides the first proof of the catastrophic deaths of the
universe's initial stars.
Around 100 million to 250 million years after the Big Bang, which happened
roughly 13.8 billion years ago, the universe's first stars were formed.
However, it is still unknown to scientists how this initial generation of
stars' mass was dispersed.
According to early universe star models, some of these celestial bodies may
have possessed masses that were equal to hundreds of suns. 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 in the later
universe (known as Type II and Type Ia supernovae), according to study team
members. Massive stars end their lives in enormous cosmic explosions called
supernovae. Pair-instability supernovae (PISNe) are the name given to these
unusual outbursts.
Astronomers refer to the elements heavier than hydrogen and helium as
metals, and all supernovae disperse these elements across the cosmos. Giant
star cores produce metals, which are then absorbed into the following
generation of stellar bodies.
These PISNe should leave behind a distinctive chemical imprint on the
following generation of stars since they differ significantly from typical
explosive stellar death throes. However, up to this point, astronomers have
not found these cosmic fingerprints.
In the latest study, a group of researchers discovered that the chemically
odd star LAMOST J1010+2358 may be the first sign of PISNe in early massive
stars.
LAMOST J1010+2358 formed in a gas cloud that was dominated by the remnants
of a 260 solar-mass star that died in a PISNe blast, according to research
using data from the Large Sky Area Multi-Object Fiber Spectroscopic
Telescope (LAMOST) survey and follow-up observations by the Subaru Telescope
in Hawaii.
The team's analysis of the chemical composition revealed that sodium and
cobalt were exceedingly rare and that there was a wide range between
elements with odd and even numbers of electrons.
This is important because PISNe are generated by an instability brought on
by the generation of electron and anti-electron pairs, also known as
positrons. This instability causes a highly large star's core thermal
pressure to drop and causes a partial collapse.
According to
research
co-author Zhao Gang, a professor at the National Astronomical Observatories
of the Chinese Academy of Sciences (NAOC), "it provides an essential clue to
constraining the initial mass function in the early universe." Before this
study, the metal-poor stars had not shown any signs of supernovae from such
big stars.
The scientists also discovered that LAMOST J1010+2358 has a substantially
higher iron content than other metal-poor stars in the galactic halo that
are the same age. This implies that second-generation stars formed in clouds
containing PISNe's gaseous remnants may have more heavy elements than
previously assumed.
Finding proof of these early pair-instability supernovae is one of the holy
grails of looking for metal-poor stars, according to astronomer and former
Harvard University astronomy department head Avi Loeb, who was not involved
in the study.
The team’s research is detailed in a paper published online today
(June 7) in the
journal Nature.
