Astronomy/Supernovae

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Question
What makes a supernova turn into a neutron star?

Answer
Hi Ana,

A neutron star is the result of a supernova (i.e. a star both goes supernova and turns into a neutron star).  This happens with stars 10 times or more the mass of our Sun. A supernova is when a star collapses due to gravity and subsequently blows up (an implosion).  The core of all stars are layered like an onion, with the heavier elements (like iron) in the center, while the lighter elements (like hydrogen) on the outside.  Nuclear fusion, which is the process of combining lighter elements to form heavier elements and produce energy, is the fuel source of stars.  When two elements are fused, let's say two hydrogens, you form a new element, in this case helium, plus some leftover particles (junk) and energy (heat).  

As a star keeps fusing elements together, you get more heavy elements and more leftover particles (essentially junk).  However, these leftover particles are a burden, as they are not doing anything but adding extra weight, which gravity is trying to pull towards the center of the star, creating pressure in the star.  To alleviate this pressure, the star burns more fuel to actually push this material further away, like a steam valve on a tea kettle.  However, since the star is creating more heavy elements, more leftover particles are being creating, which causes even more fuel to be used (and so on).  

At some point, the star can not sustain this and gravity wins, collapsing all the material down to the core, causing it to implode (for this reason we call these core-collapse supernova).  However, as gravity causes everything to collapse down to the center, it causes the core of the star, which is made of iron, to being greatly compressed.   Since this iron is so dense, it can't blow up in the supernova explosion, and is left over after the explosion, and this is what we call a neutron star.

I hope this answers your question.

Peace,
Brad

Astronomy

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Brad Tucker

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I'm happy to answer any general questions about Astronomy, Astrophysics, and Cosmology. I'm also happy to take general, specific, and detailed questions related to supernovae, Baryonic Acoustic Oscillations, the Cosmic Microwave Background, dark matter, dark energy, and the Big Bang Theory. I'm also happy to chat about Astronomy/Astrophysics education and careers, and philosophy and science.

Experience

I am a professional research astronomer/astrophysicist/cosmologist. My research focuses on studying supernovae and using them to measure the properties of the Universe, such as how fast it is growing and what it is made of. I also frequently give talks to school groups and the public, and am a regular guest on various radio stations.

Organizations
Current Research Fellow at Mt. Stromlo Observatory, the Australian National University, and in the Department of Astronomy, University of California, Berkeley.

Publications
Lots of journals, including the Astrophysical Journal, the Astronomical Journal, and Nature. I am currently in the middle of writing my first popular book.

Education/Credentials
B.A. Philosophy, University of Notre Dame, Notre Dame, IN USA B.A. Theology, University of Notre Dame, Notre Dame, IN USA B.Sc. Physics, University of Notre Dame, Notre Dame, IN USA Ph.D. Astrophysics, Mt. Stromlo Observatory, the Australian National University, Canberra, ACT, Australia

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