English

The Envelope Kinematics and a Possible Disk Around the Class 0 Protostar within BHR7

Solar and Stellar Astrophysics 2018-04-18 v1 Astrophysics of Galaxies

Abstract

We present a characterization of the protostar embedded within the BHR7 dark cloud, based on both photometric measurements from the near-infrared to millimeter and interferometric continuum and molecular line observations at millimeter wavelengths. We find that this protostar is a Class 0 system, the youngest class of protostars, measuring its bolometric temperature to be 50.5~K, with a bolometric luminosity of 9.3~L_{\odot}. The near-infrared and \textit{Spitzer} imaging show a prominent dark lane from dust extinction separating clear bipolar outflow cavities. Observations of 13^{13}CO (J=21J=2\rightarrow1), C18^{18}O (J=21J=2\rightarrow1), and other molecular lines with the Submillimeter Array (SMA) exhibit a clear rotation signature on scales <<1300~AU. The rotation can be traced to an inner radius of \sim170~AU and the rotation curve is consistent with an R1^{-1} profile, implying that angular momentum is being conserved. Observations of the 1.3~mm dust continuum with the SMA reveal a resolved continuum source, extended in the direction of the dark lane, orthogonal to the outflow. The deconvolved size of the continuum indicates a radius of \sim100~AU for the continuum source at the assumed distance of 400~pc. The visibility amplitude profile of the continuum emission cannot be reproduced by an envelope alone and needs a compact component. Thus, we posit that the resolved continuum source could be tracing a Keplerian disk in this very young system. If we assume that the continuum radius traces a Keplerian disk (R\sim120~AU) the observed rotation profile is consistent with a protostar mass of 1.0~MM_{\odot}.

Keywords

Cite

@article{arxiv.1802.08277,
  title  = {The Envelope Kinematics and a Possible Disk Around the Class 0 Protostar within BHR7},
  author = {John J. Tobin and Steven P. Bos and Michael M. Dunham and Tyler L. Bourke and Nienke van der Marel},
  journal= {arXiv preprint arXiv:1802.08277},
  year   = {2018}
}

Comments

36 pages; 11 Figures, 2 Tables; Accepted to ApJ

R2 v1 2026-06-23T00:30:42.773Z