What about PSR B1259 -63?

I first became aware of PSR B1259 -63 by reading the book,
“Pulsar Astronomy”, Andrew Lyne and Francis Graham Smith, 4th Edition, 2012, p 163-164.

At first, and frankly, for a few years thereafter, I thought that it provided the perfect example of a Be Binary (B1 companion, M=10 Msun), with a highly eccentric orbit (e=0.9), binary period 1236.7 days, eclipse (40 days). But, then it came to my attention (Johnston, etal, MNRAS 279, 1026-1036, 1996) that the B1259 -63 pulsar had a very fast spin period: 47.76 ms, almost as fast as the Crab Pulsar spin period: 33 ms.

Therefore, we have an example of a fast pulsar in a binary system with an eccentric orbit, that may also be slowing down. However, it is also an eclipsing binary that emits x-rays at periastron passage implying that the orbital energy loss will eventually circularize the orbit of the pulsar.

So, the question arises: why hasn’t the orbit already been circularized?

The answer that NS-Capture theory proposes is that the orbit had already been circularized, but that the Be primary shell star blew off a shell of material which reduced the mass of the of the primary and caused the NS pulsar to have extra orbital energy for a circular orbit, causing it to begin a new elliptical orbit based on the new smaller mass of the primary.

TBD: calculate the amount of mass that the companion would need to expel in an exploding shell that would result in the 1.4 Msun NS to attain an elliptical orbit of eccentricity, e=0.9.