2014ApJ...795...51G

Young stars accrete mass from circumstellar disks and, in many cases, the accretion coincides with a phase of massive outflows, which can be highly collimated. Those jets emit predominantly in the optical and IR wavelength range. However, in several cases, X-ray and UV observations reveal a weak but highly energetic component in those jets. X-rays are observed both from stationary regions close to the star and from knots in the jet several hundred AU from the star. In this article, we show semianalytically that a fast stellar wind that is recollimated by the pressure from a slower, more massive disk wind can have the right properties to power stationary X-ray emission. The size of the shocked regions is compatible with observational constraints. Our calculations support a wind-wind interaction scenario for the high-energy emission near the base of young stellar object jets. For the specific case of DG Tau, a stellar wind with a mass-loss rate of 5x10^–10 M_☉/yr and a wind speed of 800 km/s reproduces the observed X-ray spectrum. We conclude that a stellar wind recollimation shock is a viable scenario to power stationary X-ray emission close to the jet launching point.