Background: Globular clusters are known to exhibit anomalous abundance trends such as the sodium-oxygen anticorrelation. This trend is thought to arise via pollution of the cluster interstellar medium from a previous generation of stars. Intermediate-mass asymptotic giant branch stars undergoing hot bottom burning (HBB) are a prime candidate for producing sodium-rich oxygen-poor material, and then expelling this material via strong stellar winds. The amount of 23 Na produced in this environment has been shown to be sensitive to uncertainties in the 22 Ne(p, γ ) 23 Na reaction rate. The 22 Ne(p, γ ) 23 Na reaction is also activated in classical nova nucleosynthesis, strongly influencing predicted isotopic abundance ratios in the Na-Al region. Therefore, improved nuclear physics uncertainties for this reaction rate are of critical importance for the identification and classification of pre-solar grains produced by classical novae. Purpose: At temperatures relevant for both HBB in AGB stars and classical nova nucleosynthesis, the 22 Ne(p, γ ) 23 Na reaction rate is dominated by narrow resonances, with additional contribution from direct capture. This study presents new strength values for seven resonances, as well as a study of direct capture. Method: The experiment was performed in inverse kinematics by impinging an intense isotopically pure beam of 22 Ne onto a windowless H 2 gas target. The 23 Na recoils and prompt γ rays were detected in coincidence using a recoil mass separator coupled to a 4π bismuth-germanate scintillator array surrounding the target. Results: For the low-energy resonances, located at center of mass energies of 149, 181, and 248 keV, we recover stength values of ωγ 149 = 0.17 +0.05 −0.04 , ωγ 181 = 2.2 ± 0.4, and ωγ 248 = 8.2 ± 0.7 μeV, respectively. These results are in broad agreement with recent studies performed by the LUNA and TUNL groups. However, for the important reference resonance at 458 keV we obtain a strength value of ωγ 458 = 0.44 ± 0.02 eV, which is significantly lower than recently reported values. This is the first time that this resonance has been studied completely independently from other resonance strengths. For the 632-keV resonance we recover a strength value of ωγ 632 = 0.48 ± 0.02 eV, which is an order of magnitude higher than a recent study. For reference resonances at 610-and 1222-keV, our strength values are in agreement with the literature. In the case of direct capture, we recover an S factor of 60 keV b, consistent with prior forward kinematics experiments. Conclusions: In summary, we have performed the first direct measurement of 22 Ne(p, γ ) 23 Na in inverse kinematics. Our results are in broad agreement with the literature, with the notable exception of the 458-keV

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Abstract. Using six years (1969−1974) of data of sunspot groups from the white light pictures of the Kodaikanal Observatory, we compute rotation rates of the leading and the following sunspots and the rate of change of longitudinal separation during their life times. We find that (i) the spots that are associated with abnormal rotation rates (i.e, rotation rates that are greater than 1σ from the mean rotation) and that approach at a separation rate of 1−2 deg/day also experience minimum longitudinal separation (∼6• −10 • ) of their foot points during the course of their evolution; (ii) spots that have a minimum separation eventually trigger flares; and (iii) events with abnormal rotation rates and minimum approaching distances of the foot points occur on average during between 50−80% of the life spans, indicating the annihilation of magnetic energy, probably below the surface. These results support the conventional physical scenario of magnetic reconnection that may be responsible for triggering flares.

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