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Title: Recollimation boundary layers as X-ray sources in young stellar jets

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 5 × 10{sup –10} M {sub ☉} yr{sup –1} and a wind speed of 800 km s{sup –1} 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 jetmore » launching point.« less
Authors:
 [1] ;  [2] ;  [3]
  1. Harvard-Smithsonian Center for Astrophysics, 60 Garden Street, Cambridge, MA 02139 (United States)
  2. Department of Astronomy, University of Virginia, P.O. Box 400325, Charlottesville, VA 22904 (United States)
  3. Hamburger Sternwarte, Gojenbergsweg 112, D-21029 Hamburg (Germany)
Publication Date:
OSTI Identifier:
22370315
Resource Type:
Journal Article
Resource Relation:
Journal Name: Astrophysical Journal; Journal Volume: 795; Journal Issue: 1; Other Information: Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
79 ASTROPHYSICS, COSMOLOGY AND ASTRONOMY; BOUNDARY LAYERS; COMPUTERIZED SIMULATION; EMISSION; INTERACTIONS; MASS TRANSFER; SHOCK WAVES; STARS; STELLAR WINDS; T TAURI STARS; VELOCITY; WAVELENGTHS; X RADIATION; X-RAY SOURCES; X-RAY SPECTRA