Thermal axions with multi-eV masses are possible in low-reheating scenarios

We revise cosmological mass bounds on hadronic axions in low-reheating scenarios, with a reheating temperature $T_{\rm RH}~\le 100$ MeV, light of the latest observations. In this situation, neutrino decoupling would be unaffected, while thermal axion relic abundance is suppressed. Moreover, are colder so that their possibly loosened. As consequence these two facts, limits relaxed. Using state-of-the-art data and characterizing axion-pion interactions at leading order chiral perturbation theory, we find standard case an bound $m_a < 0.26$ eV. However, masses \simeq 1$ eV, or heavier, allowed for temperatures RH} \lesssim 80$ MeV. Multi-eV outside sensitivity current planned solar helioscopes demand new experimental approaches to detected.