• ns1@feddit.uk
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      5 days ago

      we have assumed that Rex is comprised of a uniform nucleon fluid, with protons, neutrons and electrons in an idealised 1:8:1 ratio

      This is how the author is estimating it, they are assuming 1/9th of the mass is protons. No idea how good that assumption is though, there is a source which doesn’t look the most convincing

      • bleistift2@sopuli.xyz
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        5 days ago

        Whoopsie. I used to assume neutron stars are made of neutrons. It turns out Big Astronomy lied to me.

        • Revan343@lemmy.ca
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          5 days ago

          Neutron stars are made of neutrons in the same way that tapwater is made of water molecules: primarily, but not entirely

        • Natanael@infosec.pub
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          4 days ago

          Neutron stars have so high pressure that MOST but not all protons decay into neutrons plus electrons positrons (plus neutrinos)

          Edit: (see quote below)

          • erin@piefed.blahaj.zone
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            4 days ago

            I’m not exactly well-read on particle physics, but to my understanding neutrons and neutrinos are neutrally charged and electrons are negatively charged. Why does a proton break down into net-negatively charged particles? I assume some weird quark shenanigans.

            • Natanael@infosec.pub
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              4 days ago

              https://abc.lbl.gov/wallchart/chapters/03/2.html

              I got stuff mixed

              In beta minus decay, a neutron decays into a proton, an electron, and an antineutrino: n Æ p + e - +. In beta plus decay, a proton decays into a neutron, a positron, and a neutrino: p Æ n + e+ +n. Both reactions occur because in different regions of the Chart of the Nuclides, one or the other will move the product closer to the region of stability. These particular reactions take place because conservation laws are obeyed. Electric charge conservation requires that if an electrically neutral neutron becomes a positively charged proton, an electrically negative particle (in this case, an electron) must also be produced. Similarly, conservation of lepton number requires that if a neutron (lepton number = 0) decays into a proton (lepton number = 0) and an electron (lepton number = 1), a particle with a lepton number of -1 (in this case an antineutrino) must also be produced. The leptons emitted in beta decay did not exist in the nucleus before the decay–they are created at the instant of the decay.