Possible evidence for the 478 keV emission line from ⁷Be decay during the outburst phases of V1369 Cen

After decades of uncertainty about the origin of lithium, recent evidence suggests Galactic novae as its main astrophysical source. In this work, we present possible evidence for the first detection of the 7 Be line at 478 keV, observed with the INTEGRAL satellite. The emission temporally and spatially coincides with the outburst of the bright nova V1369 Cen, where line significance ranges from 2.5 σ to ∼1.9 σ , depending on the detection methodology used. A bootstrap analysis, assuming a fixed full width half maximum of 8 keV, provides a flux of (4.9±2.0)×10 −4 ph/cm 2 /s centred at 479.0 ± 2.5 keV, with a 2.5 σ significant excess. This flux implies a total 7 Be mass of M 7 Be = (1.2 +2.0 −0.6) × 10 −8 M ⊙ at the distance determined using several indicators, including the Gaia satellite. For a nova ejected mass estimated via radio observations, this result implies a 7 Be=Li yield corresponding to A (Li) = 7.1 +0.7 −0.3 . This value is comparable to those measured in a dozen novae through optical observations. Crucially, we confirm optically derived 7 Li yields and demonstrate the groundbreaking potential of using gamma-ray data to measure Li abundances.