Cococubed.com Neutron Star and Black Hole Initial Mass Function
Home Astronomy research   Software Infrastructure:      MESA      FLASH-X      STARLIB      MESA-Web      starkiller-astro      My instruments   White dwarf pulsations:      12C(α,γ) & overshooting      Probe of 12C(α,γ)16O      Impact of 22Ne      Impact of ν cooling      Variable white dwarfs      MC reaction rates      Micronovae      Novae   White dwarf supernova:      Stable nickel production      Remnant metallicities      Colliding white dwarfs      Merging white dwarfs      Ignition conditions      Metallicity effects      Central density effects      Detonation density      Tracer particle burning      Subsonic burning fronts      Supersonic fronts      W7 profiles   Massive stars:      Pop III with HST/JWST      Rotating progenitors      3D evolution to collapse      MC reaction rates      Pre-SN variations   Massive star supernova:      Yields of radionuclides      26Al & 60Fe      44Ti, 60Co & 56Ni      SN 1987A light curve      Constraints on Ni/Fe      An r-process      Effects of 12C +12C   Neutron Stars and Black Holes:      Black Hole spectrum      Mass Gap with LVK      Compact object IMF      He burn neutron stars   Neutrino Emission:      Neutrino emission from stars      Identifying the Pre-SN      Neutrino HR diagram      Pre-SN Beta Processes      Pre-SN neutrinos   Stars:      Hypatia catalog      SAGB stars      Nugrid Yields I      He shell convection      BBFH at 40 years      γ-rays within 100 Mpc      Iron Pseudocarbynes   Pre-Solar Grains:      C-rich presolar grains      SiC Type U/C grains      Grains from massive stars      Placing the Sun      SiC Presolar grains   Chemical Evolution:      Radionuclides in 2020s      Zone models H to Zn      Mixing ejecta   Thermodynamics, Opacities & Networks      Radiative Opacity      Skye EOS      Helm EOS      Five EOSs      Equations of State      12C(α,γ)16O Rate      Proton-rich NSE      Reaction networks      Bayesian reaction rates   Verification Problems:      Validating an astro code      Su-Olson      Cog8      Mader      RMTV      Sedov      Noh Software Instruments AAS Journals    2024 AAS YouTube    2024 AAS Peer Review Workshops 2024 ASU Energy in Everyday Life 2024 MESA Classroom Outreach and Education Materials Other Stuff:    Bicycle Adventures    Illustrations    Presentations Contact: F.X.Timmes my one page vitae, full vitae, research statement, and teaching statement.	The neutron star and black hole initial mass function (1996) In this article, using recently calculated models for massive stellar evolution and supernovae coupled to a model for Galactic chemical evolution, neutron star and black hole birth functions (number of neutron stars and black holes as a function of their mass) are determined for the Milky Way galaxy. For those stars that explode as Type II supernovae, the models give birth functions that are bimodal with peaks at 1.27 and 1.76 M$_{\odot}$ and average masses within those peaks of 1.28 and 1.73 M$_{\odot}$. For stars that explode as Type Ib there is a narrower spread of remnant masses, the average being 1.32 M$_{\odot}$, and less evidence for bimodality. These values will be increased, especially in the more massive Type II supernovae, if significant accretion continues during the initial launching of the shock, and the number of heavier neutron stars could be depleted by black hole formation. The principal reason for the dichotomy in remnant masses for Type II is the difference in the presupernova structure of stars above and below 19 M$_{\odot}$, the mass separating stars that burn carbon convectively from those that produce less carbon and burn radiatively. The Type Ib's and the lower mass group of the Type II's compare favorably with measured neutron star masses, and in particular to the Thorsett et al. (1993) determination of the average neutron star mass in 17 systems 1.35 $\pm$ 0.27 M$_{\odot}$. Variations in the exponent of a Salpeter initial mass function are shown not to affect the locations of the two peaks in the distribution function, but do affect their relative amplitudes. Sources of uncertainty, in particular placement of the mass cut and sensitivity to the explosion energy, are discussed, and estimates of the total number of neutron stars and black holes in the Galaxy are given. Accretion-induced collapse should give a unique gravitational mass of 1.27 M$_{\odot}$, although this could increase if accretion onto the newly formed star continues. A similar mass will typify stars in the 8-11 M$_{\odot}$ range (e.g., the Crab pulsar). The lightest neutron star produced is 1.15 M$_{\odot}$ for the Type II models and 1.22 M$_{\odot}$ for the Type Ib models. Altogether there are about 109 neutron stars in our Galaxy and a comparable number of black holes. Curiously, this effort has garnered attention post gravitational wave LIGO/VIRGO. Mostly not for its models, but for the one-line approximation in equation 8 relating baryonic and gravitational masses: $M_{\rm baryon} - M_{\rm grav} = \Delta M = 0.075 M_{\rm grav}^2$.