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    Uncovering the Outflow Driven by the Brown Dwarf LS-RCrA 1: Hα as a Tracer of Outflow Activity in Brown Dwarfs*


    Whelan, Emma and Ray, T.P. and Bacciotti, F. (2009) Uncovering the Outflow Driven by the Brown Dwarf LS-RCrA 1: Hα as a Tracer of Outflow Activity in Brown Dwarfs*. Astrophysical Journal Letters, 691 (L106). ISSN 0004-637X

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    Abstract

    It is now apparent that classical T Tauri-like outflows commonly accompany the formation of young brown dwarfs (BDs). To date two optical outflows have been discovered, and results presented in this Letter increase this number to three. Using spectro-astrometry, the origin of the LS-RCrA 1 forbidden emission lines in a blueshifted outflow is confirmed. The nondetection of the redshifted component of the outflow in forbidden lines, along with evidence for some separation between low- and high-velocity outflow components, does not support the hypothesis that LS-RCrA 1 has an edge-on accretion disk. The key result of this analysis is the discovery of an outflow component to the Hα line. The Hα line profile has blueshifted and redshifted features in the wings which spectro-astrometry reveals to also originate in the outflow. The discovery that Hα emission in BDs can have a significant contribution from an outflow suggests that the use of Hα line widths as a proxy of mass accretion in BDs is not clear cut. This method assumes that any contribution to the Hα line flux from a possible outflow is negligible. Finally, the fact that the Hα line traces both lobes of the outflow while only the blueshifted lobe is seen in forbidden emission points to the presence of a dust hole in the accretion disk of LS-RCrA 1. This is commonly seen in classical T Tauri stars and is assumed to signal the onset of planet formation.

    Item Type: Article
    Additional Information: *Based on data collected by UVES observations (observing runs 67.C-0549(B), 69.B-0126(A), 71.C-0429(C), and 71.C-0429(D)) at the VLT on Cerro Paranal (Chile) which is operated by the European Southern Observatory (ESO). Citation: E. T. Whelan et al 2009 ApJ 691 L106
    Keywords: ISM: jets and outflows; stars: low-mass, brown dwarfs; stars: mass loss;
    Academic Unit: Faculty of Science and Engineering > Experimental Physics
    Item ID: 9896
    Identification Number: https://doi.org/10.1088/0004-637X/691/2/L106
    Depositing User: Emma Whelan
    Date Deposited: 10 Sep 2018 15:55
    Journal or Publication Title: Astrophysical Journal Letters
    Publisher: IOP Publishing
    Refereed: Yes
    URI:

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