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A. Chakraborty, J. Ge, J. H. Debes (Penn State University), R. Brown (LPL, Arizona), D. McCarthy (Steward Observatory), C. Ftaclas (Michigan Tech. University)
We have initiated a study of the nature of faint companions to nearby stars within 25pc using the Penn State near IR Imaging Spectrometer (PIRIS) and a PICNIC 256x256 pixel array. This instrument is equipped with direct imaging modes, coronographic modes, a special Gaussian pupil mask mode, and low resolution (vision prism, R=25), medium resolution (commercial fused silica grisms, R=200 to 400), and high resolution (silicon grisms, R=1000 to 5000) spectroscopy modes from 0.8 micron to 2.4 micron. We report here initial results from our first observations of HD 190067 and other stars on the Mt. Wilson 100 inch telescope using its natural guide star Adaptive Optics System. We find the H-K color of the companion of HD 190067 to be 1.1, and H magnitude to be 10.7, suggesting that it could be a very late M type dwarf, and its central hydrogen may not burn. Low resolution (R=25) spectra of this star along with other faint companion stars were also obtained to put a constraint on their nature.