Dust entrainment in photoevaporative winds: Densities and imaging

Franz, R.; Ercolano, B.; Casassus, S.; Picogna, G.; Birnstiel, T.; Perez, S.; Rab, Ch und Sharma, A. (2022): Dust entrainment in photoevaporative winds: Densities and imaging. In: Astronomy & Astrophysics, Bd. 657, A69

Abstract

Context. X-ray- and extreme-ultraviolet- (together: XEUV-) driven photoevaporative winds acting on protoplanetary disks around young T-Tauri stars may crucially impact disk evolution, affecting both gas and dust distributions. Aims. We constrain the dust densities in a typical XEUV-driven outflow, and determine whether these winds can be observed at mu m-wavelengths. Methods. We used dust trajectories modelled atop a 2D hydrodynamical gas model of a protoplanetary disk irradiated by a central T-Tauri star. With these and two different prescriptions for the dust distribution in the underlying disk, we constructed wind density maps for individual grain sizes. We used the dust density distributions obtained to synthesise observations in scattered and polarised light. Results. For an XEUV-driven outflow around a M-* = 0 :7 M-circle dot T-Tauri star with L-X = 2 x 10(30) erg s(-1), we find a dust mass-loss rate (M) over dot (dust) less than or similar to 4 :1 x 10(11) M-circle dot yr(-1) for an optimistic estimate of dust densities in the wind (compared to (M)over dot (gas) approximate to 3 :7 x 10(-8) M-circle dot yr(-1)). The synthesised scattered-light images suggest a distinct chimney structure emerging at intensities I/I-max < 10(-4.5) (10(-3.5)) at lambda(obs) = 1 :6 (0.4) mu m, while the features in the polarised-light images are even fainter. Observations synthesised from our model do not exhibit clear features for SPHERE IRDIS, but show a faint wind signature for JWST NIRCam under optimal conditions. Conclusions. Unambiguous detections of photoevaporative XEUV winds launched from primordial disks are at least challenging with current instrumentation;this provides a possible explanation as to why disk winds are not routinely detected in scattered or polarised light. Our calculations show that disk scale heights retrieved from scattered-light observations should be only marginally affected by the presence of an XEUV wind.

• Dokumententyp: Zeitschriftenartikel
• Fakultät: Physik
• Themengebiete: 500 Naturwissenschaften und Mathematik > 530 Physik
• ISSN: 0004-6361
• Sprache: Englisch
• DFG: Gefördert durch die Deutsche Forschungsgemeinschaft (DFG) - 390783311