Detection of $^7$Be II in the Small Magellanic Cloud

Understand

We analyse high resolution spectra of two classical novae that exploded in the Small Magellanic Cloud.

• $^7$Be II resonance transitions are detected in both ASASSN-19qv and ASASSN-20ni novae.
• This is the first detection outside the Galaxy and confirms that thermo-nuclear runaway reactions, leading to the $^7$Be formation, are effective also in the low metallicity regime, characteristic of the SMC.
• Derived yields are of N($^7$Be=$^7$Li)/N(H) = (5.3 $\pm$ 0.2) $\times$ 10$^{-6}$ which are a factor 4 lower than the typical values of the Galaxy.