▁the ▁medium - resol ution ▁spectrum ▁of ▁U X ▁Ari , ▁sub sol ar ▁abund ances ▁were ▁required . ▁ ▁St ell ar ▁X - ray ▁astronom y ▁is ▁contrib uting ▁toward ▁a ▁deeper ▁understanding ▁of ▁magnetic ▁fields ▁in ▁magnet oh yd rod ynamic ▁dynam os , ▁the ▁release ▁of ▁energy ▁in ▁ten uous ▁ast ro phys ical ▁pl as mas ▁through ▁various ▁pl asma - phys ical ▁processes , ▁and ▁the ▁interactions ▁of ▁high - energy ▁radiation ▁with ▁the ▁stell ar ▁environment . ▁ ▁Current ▁wisdom ▁has ▁it ▁that ▁the ▁massive ▁cor onal ▁main ▁sequence ▁stars ▁are ▁late - A ▁or ▁early ▁F ▁stars , ▁a ▁conject ure ▁that ▁is ▁supported ▁both ▁by ▁observation ▁and ▁by ▁theory . ▁ ▁Young , ▁low - mass ▁stars ▁ ▁New ly ▁formed ▁stars ▁are ▁known ▁as ▁pre - main - sequence ▁stars ▁during ▁the ▁stage ▁of ▁stell ar ▁evolution ▁before ▁they ▁reach ▁the ▁main - sequence . ▁Stars ▁in ▁this ▁stage ▁( ages ▁< 1 0 ▁million ▁years ) ▁produce ▁X - ray s ▁in ▁their ▁stell ar ▁cor ona e . ▁However , ▁their ▁X - ray ▁emission ▁is ▁ 1 0 3 ▁to ▁ 1 0 5 ▁times ▁stronger ▁than ▁for ▁main - sequence ▁stars ▁of ▁similar ▁masses . ▁ ▁X - ray ▁emission ▁for ▁pre – main - sequence ▁stars ▁was ▁discovered ▁by ▁the ▁Ein stein ▁Observ atory . ▁This ▁X - ray ▁emission ▁is ▁primarily ▁produced ▁by ▁magnetic ▁recon nection ▁fl ares ▁in ▁the ▁stell ar ▁cor ona e , ▁with