Recent research done by scientists at the University of Würzburg in Germany reports that the Milky Way galaxy's star-formation rates are greater than previously estimated.
The discovery, led by astrophysicist Thomas Siegert and colleagues, disproves the popular belief that star formation is a steady process. The findings of the study, titled "Galactic Population Synthesis of Radioactive Nucleosynthesis Ejecta," were published in Astronomy & Astrophysics and are now available on the arXiv preprint service.
More Stars Means More Important Elements
The more stars a galaxy has, the more necessary elements it has, such as oxygen and iron, Science Alert reported. Stars are the factories that create the more complicated parts of the Universe. Their cores are nuclear furnaces that smash atoms together to forge bigger and larger atoms.
When they die, their dramatic death throes expel these heavier elements into interstellar space, where they float in clouds or are picked up by newly formed stars. Their supernova explosions are very powerful, producing heavier elements that their cores are unable to support.
Star births, like their deaths, are energizing because they develop from tight clusters in clouds of interstellar dust and gas where they collapse under gravity and avidly swallow up material from the surrounding space until their cores have enough pressure and heat to start fusion.
When they do so, they begin to create enormous stellar winds that push particles into space, as well as jets of particles driven along the magnetic field of the young star.
One element known to be produced during star death is aluminum-26, a radioactive isotope of aluminum. Aluminum-26 has a half-life of 717,000 years, which is not very long in cosmic terms. It also emits gamma radiation at a certain wavelength when it decays.
More so, aluminum-26 is found in substantial numbers in the material clouds that surround freshly formed stars. A shock wave arises when the velocity of material falling into a star surpasses the speed of sound, resulting in cosmic rays. When the rays impact with dust isotopes like aluminum-27 and silicon-28, they can generate the isotope aluminium-26.
How Fast Is the Star Formation in Milky Way?
As Science Alert reported, the radioactive decay of isotopes created during star formation produces gamma rays, which indicate that stars form at a rate of four to eight times the mass of the Sun every year. It may not seem like much, but it is two to four times greater than current estimates, indicating that Milky Way is not as peaceful as previously believed.
This has significant consequences for the knowledge of the history of the Milky Way galaxy and those surrounding Earth because the pace at which stars are produced and die may change the overall chemical makeup of a galaxy.
To find the rate of star formation, WION reports that astronomers measure the quantity of gamma radiation generated by aluminum-26 decay.
Aluminum-26 has a cyclical impact because star birth and death spew heavier materials into the cosmos. The interstellar dust produced by supernova explosions and the birth of new stars provide the Milky Way galaxy with the necessary components to restart the process.
Nevertheless, the researchers cautioned that existing models may not give an accurate picture because determining the source's location is challenging. It could be the reason why scientists could only provide a range for star formation rates rather than definite figures.
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