No Expanding Fireball: Resolving the Recurrent Nova RS Ophiuchi with Infrared Interferometry

Abstract

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 ~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 ~< 540 pc, in strong disagreement with the widely-adopted distance of ~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.

Accepted by Astrophysical Journal Letters

References in corpus (3)

• A Debris Disk Around An Isolated Young Neutron Star
• An asymmetric shock wave in the 2006 outburst of the recurrent nova RS Ophiuchi
• Few Skewed Disks Found in First Closure-Phase Survey of Herbig Ae/Be stars

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• Evidence for nonlinear diffusive shock acceleration of cosmic-rays in the 2006 outburst of the recurrent nova RS Ophiuchi
• Progenitors of Type Ia Supernovae: Binary Stars with White Dwarf Companions
• A near-infrared shock wave in the 2006 outburst of recurrent nova RS Ophiuchi
• VLTI/AMBER interferometric observations of the recurrent Nova RS Oph 5.5 days after outburst
• VLTI monitoring of the dust formation event of the Nova V1280 Sco
• Silicate dust in the environment of RS Ophiuchi following the 2006 eruption
• Optical spectroscopy of the recurrent nova RS Ophiuchi - from the outburst of 2006 to quiescence
• Milliarcsecond N-Band Observations of the Nova RS Ophiuchi: First Science with the Keck Interferometer Nuller
• Interferometric Observations of RS Ophiuchi and the Origin of the Near-IR Emission
• Interferometric Observations of V1663 Aquilae (Nova Aql 2005)
• Early multiwavelength analysis of the recurrent nova V745 Sco