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Updated 2:12 PM EST, Wed, Jan 29, 2020

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Galaxies 'Waste' Heavy Elements That can Potentially Form Planets

The immense halo of gas enveloping the Andromeda galaxy, our nearest massive galactic neighbor, is about six times larger and 1,000 times more massive than previously measured.

(Photo : NASA/STScI) The immense halo of gas enveloping the Andromeda galaxy, our nearest massive galactic neighbor, is about six times larger and 1,000 times more massive than previously measured.

Astronomers have identified how galaxies apparently "waste" a massive amount of heavy elements that are generated by their stellar nurseries as they emit these and reaching millions of light years away.

This new research by the University of Colorado Boulder reveals how more carbon, oxygen, and iron atomic particles exist in these gaseous halos that enshroud the outside regions of galaxies, which now leaves galaxies with fewer raw star making materials for planets.

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According to Benjamin Oppenheimer of the Center for Astrophysics and Space Astronomy at CU-Boulder, at first the team thought how these heavier elements would become recycled into giving birth to more future generations of stars which can also contribute in forming planetary systems and ultimately promote the building blocks of life. In this new study, it turns out that galaxies are not recycling these heavy elements very well.

This almost invisible halo of gases that surrounds galaxies is called the circumgalactic medium (CGM), where astronomers believe that this is essential in how elements in the galaxy flow in a cycle however, the exact mechanism how this works remains a mystery. For a typical galaxy that possesses the size of 30,000 to 100,000 light years in size, its CGM can reach up to millions of light years.

By using data obtained from the Cosmic Origin Spectrograph onboard NASA's Hubble Space Telescope, that is designed to study CGMs, the team studied the evolution of the Milky Way and the universe via this ultraviolet spectroscopy.

Spiral galaxies such as the Milky Way is still active in star formations and emits a bluish color, while elliptical galaxies that has little to no star formations can appear red. However, both types can contain hundreds of billions of stars that constantly emit heavy elements.

As researchers ran a series of simulations, they determined that CGMs for spiral and elliptical galaxies contain more than half of the heavier elements which suggests that galaxies are apparently not as efficient in keeping ther raw stellar material as previously thought.

These new simulations also demystify the mysterious observations of how there seems to be less oxygen around elliptical galaxies than spiral ones. According to Joop Schaye of Leiden University, Netherlands, the halo around elliptical galaxies are also hotter with temperatures over 1 million degrees Kelvin which reduces the oxygen since it is five times ionized, as detected by the COS instrument. Spiral galaxies on the other hand are only around 300,000 degrees Kelvin or 50 times hotter than the sun's surface.

The team says that this process involved a colossal amount of energy and power from exploding supernovae and supermassive black holes, to propel these heavy elements into the galaxies' halos, where this violent process usually takes 10 billion years, meaning the Milky Way's halo has been there even before the sun was born.

This new study is published in the Monthly Notices of the Royal Astronomical Society.

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