The Crab Nebula's Dynamical Age as Measured from its Northern Filamentary Jet

TL;DR

This study measures the proper motions of the Crab Nebula's northern filamentary jet, estimating its age to be around 1055 CE, closely aligning with the historic supernova event of 1054 CE, and suggesting the jet's formation during the explosion.

Contribution

It provides the first proper motion analysis of the Crab Nebula's northern jet, refining its age estimate and linking it to the original supernova explosion.

Findings

Jet experienced less acceleration than the main nebula.

Estimated explosion date is 1055 CE, close to the historic supernova.

Jet likely formed during the 1054 supernova explosion.

Abstract

We present a deep [O III] 4959,5007 image of the northern filamentary jet in the Crab Nebula taken with the 8.2m Subaru telescope. Using this image and an image taken with the KPNO 4m in 1988 (Fesen & Staker 1993), we have computed proper motions for 35 locations in the jet. The results suggest that when compared to the main body of the remnant, the jet experienced less outward acceleration from the central pulsar's rapidly expanding synchrotron nebula. The jet's apparent expansion rate yields an undecelerated explosion date for the Crab Nebula of 1055 plus or minus 24 C.E., a date much closer to the appearance of the historic 1054 C.E. guest star than the 1120 - 1140 C.E. dates estimated in previous studies using filaments located within the remnant's main nebula. Our proper motion measurements suggest the jet likely formed during the 1054 supernova explosion and represents the remnant's highest velocity knots possibly associated with a suspected N-S bipolar outflow from the supernova explosion.