plasmapy.particles.atomic.particle_mass(particle: str | int | integer | Particle | CustomParticle | Quantity, *, mass_numb: int | None = None, Z: float | None = None) Quantity[source]

Return the mass of a particle.

  • particle (particle-like) – A string representing an element, isotope, ion, or special particle; an integer representing an atomic number; or a Particle.

  • mass_numb (integer, keyword-only, optional) – The mass number of an isotope.

  • Z (integer, keyword-only, optional) – The charge number of an ion or neutral atom.


The mass of the particle.

Return type:




This function will return the ion mass for ions, the isotope mass for isotopes (when available), the standard atomic weight for elements (when available), or the mass of special particles, as appropriate.

The masses of neutrinos are not available because primarily upper limits are presently known.