I just read it. What part of it is accurate astronomy and physics, specifically?

The lack of FTL and time required to get anywhere in the outer reaches of the solar system, the hypothetical but plausible antimatter-beamed power, the rogue sub-dwarf planet, are lots of similar small details. (I won't say more lest I risk spoiling the plot.)

It's rather physiology, not physics.

More like psychology and philosophy.

Also. But note several mechanisms alien creatures used on human explorers; those were totally physiological.