▁com et , ▁as ▁well ▁as ▁emission ▁lines ▁from ▁g ase ous ▁atoms ▁and ▁mole cules ▁excited ▁to ▁flu ores c ence ▁by ▁sun light ▁and / or ▁chemical ▁re actions . ▁For ▁example , ▁the ▁chemical ▁composition ▁of ▁Com et ▁I SON ▁was ▁determined ▁by ▁spect ro sc opy ▁due ▁to ▁the ▁prominent ▁emission ▁lines ▁of ▁cy an ogen ▁( CN ), ▁as ▁well ▁as ▁two - ▁and ▁three - car bon ▁atoms ▁( C 2 ▁and ▁C 3 ). ▁Near by ▁com ets ▁can ▁even ▁be ▁seen ▁in ▁X - ray ▁as ▁solar ▁wind ▁ ions ▁flying ▁to ▁the ▁com a ▁are ▁neutral ized . ▁The ▁com et ary ▁X - ray ▁spect ra ▁therefore ▁reflect ▁the ▁state ▁of ▁the ▁solar ▁wind ▁rather ▁than ▁that ▁of ▁the ▁com et . ▁ ▁See ▁also ▁ ▁References ▁ ▁Category : S pect ro sc opy ▁▁ ▁Category : Ob serv ational ▁astronom y <0x0A> </s> ▁The ▁Water ford ▁Museum ▁of ▁Tre asures ▁() ▁is ▁a ▁museum ▁for ▁historical ▁artifact s ▁associated ▁with ▁the ▁city ▁of ▁Water ford . ▁There ▁are ▁three ▁museum s ▁in ▁the ▁Vik ing ▁Tri angle ▁collect ively ▁known ▁as ▁Water ford ▁Museum ▁of ▁Tre asures . ▁Its ▁collection ▁includes ▁the ▁ 1 4 th ▁Century ▁Water ford ▁Char ter ▁Roll . ▁ ▁Const itu ent ▁museum s ▁ ▁Museum ▁The ▁Vik ing ▁Museum ▁is ▁hous ed ▁in ▁Regin ald ' s ▁Tower . ▁Regin ald ' s ▁Tower ▁is ▁the ▁oldest ▁building ▁in ▁civ ic ▁use ▁in ▁Ireland ▁and