The Milky Way Might Be Producing More Stars Than We Thought

We might be wrong about the pace of star creation in the Milky Way, according to a study of the most energetic light in the galaxy.

The radioactive disintegration of isotopes created during star formation results in gamma radiation, which show that stars are developing at a rate of four to eight times the Sun's mass per year. Even though that may not seem like much, the fact that it is two to four times higher than current projections indicates that our galaxy may not be as quiet as we first believed.

And since the rate at which stars are formed and perish can change a galaxy's general chemical makeup, this has significant consequences for our knowledge of the development of our galaxy and those around us.

Astrophysicist Thomas Siegert of the University of Würzburg in Germany is the lead author of an article outlining the discovery, which has been approved for publishing in Astronomy & Astrophysics and is already accessible on the preprint website arXiv.

The more complicated components in our universe are made in stars. Atoms are forged into ever-larger atoms by being smashed together in their centers, which act as nuclear furnaces. These heavier elements are violently ejected into interplanetary space during their violent deaths, where they float in clouds or are absorbed by newly forming stars. They too undergo energetic supernova blasts that create even heavier elements than their centers are able to sustain.

Star births are also lively like their funerals. They originate from compact clusters in interstellar dust and gas clouds, compressing under gravity and voraciously slurping up material until there is enough pressure and heat in their centers to spark fusion. They begin to produce strong stellar winds that discharge particles into space as they move in this direction, and streams of particles propelled from their poles are accelerated along the magnetic field of the young star.

An element named aluminum-26, a radioactive form of aluminum, is one that can be produced after a star dies. In terms of the cosmos, aluminum-26 has a short half-life of 717,000 years. Additionally, it generates beta radiation with a particular frequency as it degrades.

But the material masses that encircle freshly forming stars also contain a sizable amount of aluminum-26-2. When matter enters a supernova faster than the speed of sound, a shock wave develops, which produces cosmic rays. The atom aluminum-26 can be created when the electrons interact with dust-borne isotopes like silicon-28 and aluminum-27.

Therefore, scientists can approximate the rate at which stars that create the isotope form and perish in the Milky Way and use that to establish an overall rate of star generation by looking at the budget of gamma radiation in the Universe generated by the radioactive decay of aluminum-26.

The Milky Way galaxy is thought to create stars at a pace of about two Suns' worth of material per year, according to current estimates. That's believed to be on average six or seven stars per year because the majority of Milky Way stars are much less dense than the Sun.

The aluminum-26 gamma radiation in the galaxy was counted by Siegert and his coworkers, and modeling was done to determine the most probable mechanism for this light's abundance. They discovered that a star creation rate of four to eight solar masses annually, or up to 55 stars on average, provides the best match.

This estimate can still be improved because the models did not accurately replicate the Milky Way's gamma radiation as it is presently detected and because it is difficult to determine the source's location. Because of this, the scientists were only able to provide an estimate for the star creation rate rather than a precise mass.

The team's approach, though, offers hope for a greater comprehension of how the Milky Way creates new stars. Counting the gamma radiation that is produced during star formation could be a useful method of peeping behind the veil since star formation is typically shrouded in dense gas and dust that makes it difficult to see into.

The team's research has been accepted for publication in Astronomy & Astrophysics, and is available on arXiv.