García, M., Herrero, A., Najarro, F., Camacho, I., Lennon, D. J., Urbaneja, M. A., Castro, N. 2017. Low-metallicity (sub-SMC) massive stars. Lives and Death Throes of Massive Stars, 329th Symposium of the International-Astronomical-Union (IAU) 12, 313-321, DOI: 10.1017/S1743921317003088

The double distance and metallicity frontier marked by the SMC has been finally broken with the aid of powerful multi-object spectrographs installed at 8-10m class telescopes. VLT, GTC and Keck have enabled studies of massive stars in dwarf irregular galaxies of the Local Group with poorer metal-content than the SMC. The community is working to test the predictions of evolutionary models in the low-metallicity regime, set the new standard for the metal-poor high-redshift Universe, and test the extrapolation of the physics of massive stars to environments of decreasing metallicity. In this paper, we review current knowledge on this topic.