Rapid cooling of neutron stars by hyperons and Delta isobars

摘要: It is shown that direct Urca processes with hyperons and/or nucleon isobars can occur in dense matter as long the concentration of Λ exceeds a critical value less than 3% and typically about 0.1%. The neutrino luminosities from hyperon are 5-100 times typical luminosity process, if latter process not forbidden, but they larger those expected other sources. These new provide avenues for rapid cooling neutron stars which invoke neither exotic states nor large proton fraction (of order 0.11-0.15) required