Main Question or Discussion Point
The paper goes on to describe asteroids "formed from supernova fallback material" falling into the pulsar. Why would the asteroids be formed after the supernova? More importantly, how could an asteroid form from supernova remnants?Abstract
Debris disks and asteroid belts are expected to form around young pulsars due to fallback material from their original supernova explosions. Disk material may migrate inwards and interact with a pulsar’s magnetosphere, causing changes in torque and emission. Long term monitoring of PSR J0738−4042 reveals both effects. The pulse shape changes multiple times between 1988 and 2012. The torque, inferred via the derivative of the rotational period, changes abruptly from September 2005. This change is accompanied by an emergent radio component that drifts with respect to the rest of the pulse. No known intrinsic pulsar processes can explain these timing and radio emission signatures. The data lead us to postulate that we are witnessing an encounter with an asteroid or in-falling debris from a disk.
Source: arXiv : 1311.3541v1 [PDF]
If a star with less than ~9 solar masses had planets and asteroids, then those planets and asteroids would still be there after the supernova. Supernova ejecta are charged particles traveling in excess of 10,000 km/s for Type I & II SNe (less than 8,000 km/s for Type Iax SNe). That may be sufficient to strip off layers of atmosphere from planets, but hardly capable of destroying rocky asteroids or planets. Naturally, a star that goes from 9 solar masses to less than 3 solar masses in just a second or two is going to dramatically change the orbits of any object in that solar system, but the supernova would not destroy those objects.
I do not doubt that the pulsar in question is being pelted by asteroids, as they claim. However, I do dispute that these asteroids were formed after the supernova. I think all planets and asteroids around neutron stars already existed before the star went supernova.
Planets and asteroids do not form directly from supernova remnants, there must be another trigger involved first. Such as another supernova blast from another star that compresses the extremely disbursed supernova remnant gases. Without that trigger the supernova remnants are too disbursed, and getting further disbursed as it continues to travel, to form anything solid.
Does anyone think it is possible for a supernova, without any outside influences to trigger a collapse of the supernova remnants, could form asteroids or planets after the supernova? If so, I would be interested in knowing how it would be possible.