When first discovered, many believed that the planets of PSR 1257+12 were the barren cores of giant planets that had survived the supernova of their host star. Recent studies, however, have shown that they more likely formed after the supernova and from material captured by the pulsar from a stellar companion. If this is the case, then the planets of PSR 1257+12 are not the withered husks of ancient worlds. Instead, they are young worlds, less than a billion years old. With a mass similar to that of the moon, PSR 1257+12 a is probably like the moon in other ways as well. With its low mass, it long ago cooled to the point where volcanism and tectonics subsided. It is probably heavily cratered, still bearing the scars of its battered birth. With its formation close to the inner edge of the protoplanetary disk, it is likely that Planet a contains a great deal of heavy elements, like iron. In this regard, it is would be more akin to a miniature Mercury than the iron poor moon. Mercury has a magnetic field, albeit much weaker than the Earth's. Planet a probably had a magnetic field early in life as well, but with such little mass to keep it's core molten, that magnetic field may have already dissipated. Any remaining field is likely very weak. This, combined with Planet a's low gravity make it unlikely that the planet has an atmosphere. With little or no protective magnetic envelope, any gas molecules at the planet's surface would be excited by the radiation of the pulsar and be lost by the planet's weak gravitational pull. If the intensity of the pulsar's radiation is great enough, it is possible that Planet a is being slowly eroded, "sand blasted" by a barrage of elementary particles. Surface material on the day side may become ionized and glow a faint blue as it is excited to escape velocity and lost to space. If this is the case, then the planet may have a tenuous atmosphere after all, albeit one caused by material being lost directly from the solid surface.
 But the radiation coming from the pulsar may not be as intense as it would first seem. Assuming that the planets orbit in the same plane as PSR 1257+12's own rotation and given that the orbital inclination of the entire system seems to be about 50°, it is unlikely that the pulsar's beam actually hits the planets. Even if the beam does cross the orbits of the planets, the planets would only pass through the beam for short periods of time. The pulsar is giving of other radiation, however. Studies of the overall particle luminosity of PSR 1257+12 indicate that the pulsar's radiation flux is of the same order of magnitude as that from the sun. This means that the effective temperature of the three pulsar planets would only be a few hundred kelvin, similar to that of Mars or Jupiter. The radiation from PSR 1257+12 would contain less actual light and a great deal more charged particles than solar radiation, but the total flux may not be sufficient for the "sand blasting" of Planet a. Both Mercury and the moon do suffer ablation from the solar wind, but the mass lost in this way is insignificant. This may be the case with Planet a as well. It's ionized glow may be more akin to the electroglow of Uranus and only faintly visible, if at all. It has also been suggested that the intense ultraviolet and X-ray radiation from the pulsar might cause the surface of the pulsar planets to fluoresce. Fluorescing minerals are rare, however. The terrestrial planets of our own solar system are dominated by basalt and other non-fluorescing materials, and it is likely that this is the case with the pulsar planets as well. Very little of the radiation coming from the pulsar is in the form of visible light. To this author's knowledge, the absolute magnitude of PSR 1257+12 is not known, but a comparison can be made with another stellar remnant, the neutron star RX J185635-3754. This object is about 200 light years away with an apparent magnitude of 26. From this we can calculate an absolute magnitude of just 22.06. PSR 1257+12 is much older and probably dimmer than RX J185635-3754, but if we use this magnitude as an approximation we can determine how bright the pulsar would appear from the innermost planet. The answer is not very bright at all. PSR 1257+12 would have the same brightness from Planet a, 0.19 AU away, as the sun would have from a distance of 500 AU. That's only 0.2 lux, or about as bright as the full moon. Even from a planet with an orbital distance less than a half that of Mercury, the pulsar would only look like an overbright star. Given its close proximity to the pulsar, Planet a is most likely tidally locked. One side of the planet would always face the pulsar. From the surface of its innermost world, the pulsar would never rise or set, but sit motionless in the sky. The opposite side of the planet, safe from the pulsar's radiation, would be locked in a frigid eternal darkness.
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