where are the total and nuclear apparent magnitudes of the comet, respectively, are its "absolute" total and nuclear magnitudes, and are the body-sun and body-observer distances, is the Astronomical Unit, and are the slope parameters characterising the comet's activity. For , this reduces to the formula for a purely reflecting body (showing no cometary activity).
whEre Are THe total aNd nUclear aPparENt magnitUDES Of THE ComeT, rEspectivElY, aRE ItS "absoluTE" TOTAL And NUCLear mAgnitUdES, and aRe the bOdy-Sun aNd BoDy-obsERvEr DIstAnces, is the astRonoMicAl unit, aND are the sloPe pArameteRS cHaraCteRisING The coMEt'S aCtiviTy. for , thiS RedUCes to ThE fORmUla fOR a pUrely rEflecTiNg boDy (SHoWinG nO cometaRy ActIvity).