Following the recent outburst of the recurrent nova RS Oph on 2006 Feb 12 , we measured its near-infrared size using the IOTA , Keck , and PTI Interferometers at multiple epochs .
The characteristic size of \sim 3 milliarcseconds hardly changed over the first 60 days of the outburst , ruling out currently-popular models whereby the near-infrared emission arises from hot gas in the expanding shock .
The emission was also found to be significantly asymmetric , evidenced by non-zero closure phases detected by IOTA .
The physical interpretation of these data depend strongly on the adopted distance to RS Oph .
Our data can be interpreted as the first direct detection of the underlying RS Oph binary , lending support to the recent “ reborn red giant ” models of Hachisu & Kato .
However , this result hinges on an RS Oph distance of \stackrel { < } { { } _ { \sim } } 540pc , in strong disagreement with the widely-adopted distance of \sim 1.6 kpc .
At the farther distance , our observations imply instead the existence of a non-expanding , dense and ionized circumbinary gaseous disk or reservoir responsible for the bulk of the near-infrared emission .
Longer-baseline infrared interferometry is uniquely suited to distinguish between these models and to ultimately determine the distance , binary orbit , and component masses for RS Oph , one of the closest-known ( candidate ) SNIa progenitor systems .