[{"n": "Parallax", "u": "/e/part-1/parallax/", "s": "Parallax measures distance through apparent shift in viewpoint."}, {"n": "Parsec", "u": "/e/part-1/parsec/", "s": "Unit of distance defined by one arcsecond of parallax."}, {"n": "Planetary nebula", "u": "/e/part-1/planetary-nebula/", "s": "Expanding shells of ionized gas from dying stars."}, {"n": "Planetary system", "u": "/e/part-1/planetary-system/", "s": "A star's family of orbiting worlds and debris."}, {"n": "Pleiades", "u": "/e/part-1/pleiades/", "s": "A nearby open star cluster visible to the naked eye."}, {"n": "Protostar", "u": "/e/part-1/protostar/", "s": "Earliest phase of stellar evolution, gathering mass from a molecular cloud."}, {"n": "Pulsar", "u": "/e/part-1/pulsar/", "s": "Rotating neutron stars emitting regular electromagnetic pulses."}, {"n": "Red giant", "u": "/e/part-1/red-giant/", "s": "A late-phase, luminous giant star with an inflated atmosphere."}, {"n": "Ring Nebula", "u": "/e/part-1/ring-nebula/", "s": "Messier 57, a glowing shell of gas cast off by a dying star in the constellation Lyra."}, {"n": "Solar System", "u": "/e/part-1/solar-system/", "s": "The Sun and all objects gravitationally bound to it."}, {"n": "Star cluster", "u": "/e/part-1/star-cluster/", "s": "Groups of stars sharing origin, held by gravity."}, {"n": "Star formation", "u": "/e/part-1/star-formation/", "s": "Process by which dense molecular cloud regions collapse into stars."}, {"n": "Star system", "u": "/e/part-1/star-system/", "s": "Gravitationally bound groups of stars, from binaries to complex multiples."}, {"n": "Stellar black hole", "u": "/e/part-1/stellar-black-hole/", "s": "Black holes formed from stellar collapse."}, {"n": "Stellar classification", "u": "/e/part-1/stellar-classification/", "s": "System for classifying stars by spectral and luminosity characteristics."}, {"n": "Stellar evolution", "u": "/e/part-1/stellar-evolution/", "s": "Stars evolve from gas clouds to white dwarfs, neutron stars, or black holes."}, {"n": "Stellar kinematics", "u": "/e/part-1/stellar-kinematics/", "s": "Observational study of star motions through space."}, {"n": "Stellar magnetic field", "u": "/e/part-1/stellar-magnetic-field/", "s": "Magnetic fields generated by plasma motion shape stellar activity."}, {"n": "Stellar structure", "u": "/e/part-1/stellar-structure/", "s": "Models describing internal star structure and energy transport."}]