Antonio Manaytay – Fourth Estate Contributor
Oxford, England, United Kingdom (4E) – An international team of astronomers believed the discovery of overabundance of massive stars in a neighboring galaxy could shed light how stars had transformed the early Universe into what it is today.
The study, published in the journal Science, used the ESO’s Very Large Telescope which is part of the VLT-FLAMES Tarantula Survey (VFTS) to observe a giant nursery for stars known as Tarantula nebula, composed of about 1,000 massive stars in 30 Doradus.
“We were astonished when we realized that 30 Doradus has formed many more massive stars than expected,” lead author Fabian Schneider, a Hintze Research Fellow in the University of Oxford’s Department of Physics, said.
The astronomers used the so-called initial mass function (IMF) derived from the analyses of some 250 stars with masses of 15 to 200 Suns. Previous studies have shown that the more massive the stars they become rarer in the Universe.
Less than a percent of all stars are born with masses more than 10 Suns. To measure the number of massive stars is most difficult owing to their scarcity and only few places in the Universe where they can be found.
Massive stars are important in the study because of their significant influence in the cosmic environment. These stars could become giant supernovae at the end of their lives forming neutron stars and black holes.
“We have not only been surprised by the sheer number of massive stars, but also that their IMF is densely sampled up to 200 solar masses,” co-author Hugues Sana from the University of Leuven in Belgium, said.
The discovery of the stars with masses up to 200 Suns in 30 Doradus had settled the dispute of their existence.
“In fact, our results suggest that most of the stellar is actually no longer in low-mass stars, but a significant fraction is in high-mass stars,” VFTS principal investigator Chris Evans from the Science and Technology Facilities Council, said.
“Our results have far-reaching consequences for the understanding of our cosmos: there might be 70% more supernovae, a tripling of the chemical yields and towards four times the ionising radiation from massive star populations,” Fabian Schneider, member of the team, added.
It is also possible that the rate black holes are formed could increase by 180 percent, he said. The probability of prediction to be correct is high based on the increasing number of binary black holes mergers, which was recently observed based on the gravitational wave signals.
Stars are engines in the Universe producing chemical elements heavier than helium. The oxygen by which humans breathe and the iron in the blood are among the elements produced by stars.
In the stars’ lifetime, they produced abundant ionizing radiation and kinetic energy through strong stellar winds responsible for the re-brightening of stars during the cosmic Dark Ages. The influence exerted by these stars served as drivers of the evolution of the Universe.
“To quantitatively understand all these feedback mechanisms and hence the role of massive stars in the Universe, we need to know how many of these behemoths are born,” study co-author Philipp Podsiadlowski from the University of Oxford, said.
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