Kepler planet candidates require both spectroscopic and imaging follow-up observations to rule out false positives and detect blended stars .
Traditionally , spectroscopy and high-resolution imaging have probed different host star companion parameter spaces , the former detecting tight binaries and the latter detecting wider bound companions as well as chance background stars .
In this paper , we examine a sample of eleven Kepler host stars with companions detected by two techniques – near-infrared adaptive optics and/or optical speckle interferometry imaging , and a new spectroscopic deblending method .
We compare the companion effective temperatures ( T _ { eff } ) and flux ratios ( F _ { B } /F _ { A } , where A is the primary and B is the companion ) derived from each technique , and find no cases where both companion parameters agree within 1 \sigma errors .
In 3/11 cases the companion T _ { eff } values agree within 1 \sigma errors , and in 2/11 cases the companion F _ { B } /F _ { A } values agree within 1 \sigma errors .
Examining each Kepler system individually considering multiple avenues ( isochrone mapping , contrast curves , probability of being bound ) , we suggest two cases for which the techniques most likely agree in their companion detections ( detect the same companion star ) .
Overall , our results support the advantage that spectroscopic deblending technique has for finding very close-in companions ( \theta \lesssim 0.02-0.05 \arcsec ) that are not easily detectable with imaging .
However , we also specifically show how high-contrast AO and speckle imaging observations detect companions at larger separations ( \theta \geq 0.02-0.05 \arcsec ) that are missed by the spectroscopic technique , provide additional information for characterizing the companion and its potential contamination ( e.g. , position angle , separation , magnitude differences ) , and cover a wider range of primary star effective temperatures .
The investigation presented here illustrates the utility of combining the two techniques to reveal higher-order multiples in known planet-hosting systems .