  Massive hot stars produce dense ultraviolet (UV) photon fields in their
surroundings. If a very high-energy (VHE) gamma-ray emitter is located close to
the star, then gamma-rays are absorbed in the stellar photon field, creating
secondary (electron-positron) pairs. We study the broadband emission of these
secondary pairs in the stellar photon and magnetic fields. Under certain
assumptions on the stellar wind and the magnetic field in the surroundings of a
massive hot star, we calculate the steady state energy distribution of
secondary pairs created in the system and its radiation from radio to
gamma-rays. Under the ambient magnetic field, possibly high enough to suppress
electromagnetic (EM) cascading, the energy of secondary pairs is radiated via
synchrotron and single IC scattering producing radio-to-gamma-ray radiation.
The synchrotron spectral energy distribution (SED) is hard, peaks around X-ray
energies, and becomes softer. The IC SED is hard as well and peaks around 10
GeV, becoming also softer at higher energies due to synchrotron loss dominance.
The radio emission from secondary pairs is moderate and detectable as a
point-like and/or extended source. In X-rays, the secondary pair synchrotron
component may be dominant. At energies <10 GeV, the secondary pair IC radiation
may be the dominant primary gamma-ray emission and possibly detectable by the
next generation of instruments.
