Aspects of AdS$_2$ classification in M-theory: Solutions with mesonic and baryonic charges

We construct necessary and sufficient geometric conditions for a class of AdS$_2$ solutions of M-theory with, at least, minimal supersymmetry to exist. We generalize previous results in the literature for ${\cal N}=(2,0)$ supersymmetry in AdS$_2$ to ${\cal N}=(1,0)$. When the solution can be locally described as AdS$_2\times \Sigma_g \times \,$SE$_7$ with $\Sigma_g$ a Riemann surface of genus $g$ and SE$_7$ a seven-dimensional Sasaki-Einstein manifold, we clarify and unify various solutions present in the literature. In the case of SE$_7=Q^{1,1,1}$ we find a new solution with baryonic and mesonic charges turned on simultaneously.