On the Progenitor of the Crab Pulsar

Abstract

The Crab supernova is interesting because we know that it was not a binary at death, the outcome was a neutron star, and because of the supernova remnant's apparently low energy and mass. Using Gaia EDR3 parallaxes and photometry, we examine the stellar population local to the Crab in a cylinder with a projected radius of 100 pc and parallax range $0.427 < \varpi < 0.619$ mas set by the uncertainties in the Crab's parallax. We also individually model the most luminous stars local to the Crab. The two most luminous stars are blue, roughly main sequence stars with masses of $\sim11 M_{\odot}$. We estimate the stellar population's age distribution using Solar metallicity PARSEC isochrones. The estimated age distribution of the 205 $M_{G} < 0$ stars modestly favor lower mass stars consistent with an AGB star or a lower mass binary merger as the progenitor, but we cannot rule out higher masses. This may be driven by contamination due to the $\sim700$ pc length of the cylinder in distance.