▁fields ▁in ▁ast ro phys ical ▁bodies . ▁If ▁some ▁of ▁the ▁stell ar ▁magnetic ▁fields ▁are ▁really ▁induced ▁by ▁dynam os , ▁then ▁field ▁strength ▁might ▁be ▁associated ▁with ▁rotation ▁rate . ▁ ▁Astronom ical ▁models ▁ ▁From ▁the ▁observed ▁X - ray ▁spectrum , ▁combined ▁with ▁spectral ▁emission ▁results ▁for ▁other ▁w avel ength ▁ranges , ▁an ▁astronom ical ▁model ▁address ing ▁the ▁likely ▁source ▁of ▁X - ray ▁emission ▁can ▁be ▁constructed . ▁For ▁example , ▁with ▁Sc or pi us ▁X - 1 ▁the ▁X - ray ▁spectrum ▁ste ep ly ▁dro ps ▁off ▁as ▁X - ray ▁energy ▁increases ▁up ▁to ▁ 2 0 ▁ke V , ▁which ▁is ▁likely ▁for ▁a ▁thermal - pl asma ▁mechanism . ▁In ▁addition , ▁there ▁is ▁no ▁radio ▁emission , ▁and ▁the ▁visible ▁continu um ▁is ▁roughly ▁what ▁would ▁be ▁expected ▁from ▁a ▁hot ▁pl asma ▁fitting ▁the ▁observed ▁X - ray ▁flux . ▁The ▁pl asma ▁could ▁be ▁a ▁cor onal ▁cloud ▁of ▁a ▁central ▁object ▁or ▁a ▁trans ient ▁pl asma , ▁where ▁the ▁energy ▁source ▁is ▁unknown , ▁but ▁could ▁be ▁related ▁to ▁the ▁idea ▁of ▁a ▁close ▁binary . ▁ ▁In ▁the ▁C rab ▁Neb ula ▁X - ray ▁spectrum ▁there ▁are ▁three ▁features ▁that ▁differ ▁greatly ▁from ▁Sc or pi us ▁X - 1 : ▁its ▁spectrum ▁is ▁much ▁harder , ▁its ▁source ▁diameter ▁is ▁in ▁light - year s ▁( ly ) s , ▁not ▁astronom ical ▁units ▁( AU ), ▁and ▁its ▁radio ▁and