Peculiar Radio–X-Ray Relationship in Active Stars

Abstract The empirical relationship between the nonthermal 5 GHz radio luminosity and soft X-ray of active stellar coronae, canonically called Güdel–Benz relationship, has been a cornerstone astronomy, as it explicitly ties emission to coronal heating mechanisms. extends from microflares on Sun coronae most stars suggesting that are heated by flare-like process. is thought originate consistent partition available flare energy into relativistic charges, which emit in radio-band via incoherent gyrosynchrotron mechanism, bulk plasma, emits band Bremsstrahlung mechanism. Consequently, coherent substellar objects not expected adhere this observed ultracool dwarf brown dwarfs. Here we report population radio-detected chromospherically surprisingly follow despite their being classified virtue its high circularly polarized fraction brightness temperature. Our results prompt reexamination physics behind implication for mechanism particle acceleration stars, phenomenological connection solar flares.