S. Mcmuldroch et al., THE CIRCUMSTELLAR ENVIRONMENT OF THE FU ORIONIS PRE-OUTBURST CANDIDATE V1331-CYGNI, The Astronomical journal, 106(6), 1993, pp. 2477-2485
High resolution (approximately 4'') aperture synthesis maps of the CO
(1 --> 0), (CO)-C-13 (1 --> 0), (CO)-C-13 (2 --> 1), and associated co
ntinuum emission from the FU Orionis candidate V1331 Cygni reveal a ma
ssive, 0.5 +/- 0.15 M., circumstellar disk surrounded by a flattened g
aseous envelope, 6000 X 4400 AU in size, mass greater-than-or-equal-to
0.32 M.. These images and lower resolution measurements also trace a
bipolar outflow and gaseous ring, 4.1 by 2.8 X 10(4) AU, mass greater-
than-or-equal-to 0.07 M., radially expanding at 22 +/- 4 km s-1. We su
ggest this ring is a swept-up gaseous torus from an energetic mass eje
ction stage, possibly an FU Orionis outburst or outbursts, approximate
ly 4 X 10(3) yr ago that imparted greater-than-or-equal-to 10(45) ergs
into the ambient cloud.