We report observations of the nova RS Ophiuchi ( RS Oph ) using the Keck Interferometer Nuller ( KIN ) , approximately 3.8 days following the most recent outburst that occurred on 2006 February 12 .
These observations represent the first scientific results from the KIN , which operates in N-band from 8 to 12.5 \mu m in a nulling mode .
The nulling technique is the sparse aperture equivalent of the conventional coronagraphic technique used in filled aperture telescopes .
In this mode the stellar light itself is suppressed by a destructive fringe , effectively enhancing the contrast of the circumstellar material located near the star .
By fitting the unique KIN data , we have obtained an angular size of the mid-infrared continuum of 6.2 , 4.0 , or 5.4 mas for a disk profile , gaussian profile ( FWHM ) , and shell profile respectively .
The data show evidence of enhanced neutral atomic hydrogen emission and atomic metals including silicon located in the inner spatial regime near the white dwarf ( WD ) relative to the outer regime .
There are also nebular emission lines and evidence of hot silicate dust in the outer spatial region , centered at \sim 17 AU from the WD , that are not found in the inner regime .
Our evidence suggests that these features have been excited by the nova flash in the outer spatial regime before the blast wave reached these regions .
These identifications support a model in which the dust appears to be present between outbursts and is not created during the outburst event .
We further discuss the present results in terms of a unifying model of the system that includes an increase in density in the plane of the orbit of the two stars created by a spiral shock wave caused by the motion of the stars through the cool wind of the red giant star .
These data show the power and potential of the nulling technique which has been developed for the detection of Earth-like planets around nearby stars for the Terrestrial Planet Finder Mission and Darwin missions .