String Stars – You Heard It Here First!
February 22, 2009 1 Comment
I remember the days when we were all amazed at the concept of a white dwarf star; the final evolutionary state of most stars after their gravitational collapse. It can’t collapse any further due to something called electron degeneracy pressure. I always visualized it by imagining atoms jammed together to the point where their electron shells were nearly touching. A white dwarf’s density was such that a teaspoonful would weigh as much as an elephant. They are about the size of the earth.
But there was an even more bizarre concept – the neutron star. Still more dense, it was proposed by Baade and Zwicky in 1933, a year after the neutron was discovered. For a star that has more mass than the Chandrasekhar limit, or 1.44 solar masses, when it collapses at the end of its life, its density is even enough to overcome the forces that hold a white dwarf together. In the late 60’s, one was actually observed and by the 70’s, the concept was considered to be well accepted by most astronomers. Neutron stars can’t collapse any further due to the Pauli exclusion principle. I always visualized it by imagining neutrons jammed together to the point where they were nearly touching. A neutron star is maybe a billion times denser than a white dwarf. They are about the size of Manhattan.
But then, I thought, what if the mass of the star was so large that even the neutrons collapsed into their constituents, quarks? Well, I don’t know if anyone else had such an idea and now, doing a little web research, I can’t seem to put my finger on when such a concept was first proposed. But I’m starting to see a buzz about quark stars. In 2008, astrophysicists Denis Leahy and Rachid Ouyed proposed the quark star as the result of super-supernovae (http://www.space.com/scienceastronomy/080603-aas-neutron-quark.html). And now, astrophysicists from the University of Hong Kong have presented evidence of a quark star in super-supernova SN 1987A (http://www.newscientist.com/article/mg20126964.700-quark-star-may-hold-secret-to-early-universe.html)
So, now I wonder, what next? Quarks probably have their own sub-quark constituents. String theorists say quarks are made of vibrating strings. If so, could a massive enough star, or a dense enough hunk of matter overcome “quark degeneracy” and collapse into a “String Star?” A star consisting of string material that is so compressed it can vibrate anymore?
So I searched the web and am proud to say that I have found no such proposal. So, I hereby claim it. Someday, someone will lay claim to discovering a string star. You heard it here, first. 🙂