The complex circumstellar ejecta of highly evolved , cool hypergiants are indicative of multiple , asymmetric mass loss events .
To explore whether such episodic , non-isotropic mass loss may be driven by surface magnetic activity , we have observed the archetypical cool hypergiant VY CMa with the XMM-Newton X-ray satellite observatory .
The hypergiant itself is not detected in these observations .
From the upper limit on the X-ray flux from VY CMa at the time of our observations ( F _ { X,UL } ~ { } \approx~ { } 8 \times 10 ^ { -14 } { ~ { } erg~ { } cm } ^ { -2 } { ~ { } s } ^ { -1 } , corresponding to \log~ { } L _ { X } / L _ { bol } \leq - 8 ) , we estimate an average surface magnetic field strength fB \leq 2 \times 10 ^ { -3 } G ( where f is the filling factor of magnetically active surface regions ) .
These X-ray results for VY CMa represent the most stringent constraints to date on the magnetic field strength near the surface of a hypergiant .
VY CMa ’ s mass loss is episodic and may have been in a state of low surface magnetic activity during the XMM observations .
The XMM observations also yield detections of more than 100 X-ray sources within \sim 15 ^ { \prime } of VY CMa , roughly 50 of which have near-infrared counterparts .
Analysis of X-ray hardness ratios and IR colors indicates that some of these field sources may be young , late-type stars associated with VY CMa , its adjacent molecular cloud complex , and the young cluster NGC 2362 .
Further study of the VY CMa field is warranted , given the potential to ascertain the evolutionary timescale of this enigmatic , massive star .