Background : The ^ { 22 } Ne ( p , \gamma ) ^ { 23 } Na reaction is the most uncertain process in the neon-sodium cycle of hydrogen burning .
At temperatures relevant for nucleosynthesis in asymptotic giant branch stars and classical novae , its uncertainty is mainly due to a large number of predicted but hitherto unobserved resonances at low energy .

Purpose : A new direct study of low energy ^ { 22 } Ne ( p , \gamma ) ^ { 23 } Na resonances has been performed at the Laboratory for Underground Nuclear Astrophysics ( LUNA ) , in the Gran Sasso National Laboratory , Italy .

Method : The proton capture on ^ { 22 } Ne was investigated in direct kinematics , delivering an intense proton beam to a ^ { 22 } Ne gas target . \gamma rays were detected with two high-purity germanium detectors enclosed in a copper and lead shielding suppressing environmental radioactivity .

Results : Three resonances at 156.2 keV ( \omega \gamma = ( 1.48 \pm 0.10 ) \cdot 10 ^ { -7 } eV ) , 189.5 keV ( \omega \gamma = ( 1.87 \pm 0.06 ) \cdot 10 ^ { -6 } eV ) and 259.7 keV ( \omega \gamma = ( 6.89 \pm 0.16 ) \cdot 10 ^ { -6 } eV ) proton beam energy , respectively , have been observed for the first time .
For the levels at E _ { x } = 8943.5 , 8975.3 , and 9042.4 keV excitation energy corresponding to the new resonances , the \gamma -decay branching ratios have been precisely measured .
Three additional , tentative resonances at 71 , 105 and 215 keV proton beam energy , respectively , were not observed here .
For the strengths of these resonances , experimental upper limits have been derived that are significantly more stringent than the upper limits reported in the literature .

Conclusions : Based on the present experimental data and also previous literature data , an updated thermonuclear reaction rate is provided in tabular and parametric form .
The new reaction rate is significantly higher than previous evaluations at temperatures of 0.08-0.3 GK .