The term digital twin refers to a comprehensive digital representation of a physical system that serves as its real-time digital counterpart. Digital twin goes beyond traditional computer-aided applications and represents a two-way communication bridge between the physical and the digital worlds. In 2020, Gartner identified digital twin as one of the ten technology trends capable of a profound impact on modern society. While digital twin originates from the manufacturing domain, its recent underpinning technology maturation makes it suitable to all those domains where there is a need for studying virtual interactions with the physical environment. Despite its peak of research and adoption, there are still some grey areas related to certain aspects of digital twin such as enabling technologies and reported benefits. In this paper, we report on the planning, execution and results of a systematic mapping study, which aimed at providing a structured and detailed snapshot of the current application of digital twin, enabling technologies, reported benefits and application domains. Starting from an initial set of 675 publications, we identified 26 primary studies, which we have analysed through a rigorous data extraction, analysis and synthesis process. Based on the collected data, we drew relations between digital twin and the production domain.