Prospects for Characterizing Host Stars of the Planetary System Detections Predicted for the Korean Microlensing Telescope Network

Abstract

I investigate the possibility of constraining the flux of the lens (i.e., host star) for the types of planetary systems the Korean Microlensing Telescope Network is predicted to find. I examine the potential to obtain lens flux measurements by 1) imaging a lens once it is spatially resolved from the source, 2) measuring the elongation of the point spread function of the microlensing target (lens+source) when the lens and source are still unresolved, and 3) taking prompt follow-up photometry. In each case I simulate observing programs for a representative example of current ground-based adaptive optics (AO) facilities (specifically NACO on VLT), future ground-based AO facilities (GMTIFS on GMT), and future space telescopes (NIRCAM on $JWST$). Given the predicted distribution of relative lens-source proper motions, I find that the lens flux could be measured to a precision of ${\sigma }_{H_{\ell }}\le 0.1$ for $\gtrsim$60$\%$ of planet detections $\ge$5 years after each microlensing event, for a simulated observing program using GMT that images resolved lenses. NIRCAM on $JWST$ would be able to carry out equivalently high-precision measurements for $\sim$28$\%$ of events $\Delta t$ = 10 years after each event by imaging resolved lenses. I also explore the effects various blend components would have on the mass derived from prompt follow-up photometry, including companions to the lens, companions to the source, and unassociated interloping stars. I find that undetected blend stars would cause catastrophic failures (i.e., $>$50$\%$ fractional uncertainty in the inferred lens mass) for $\lesssim$(16$\cdot f_{\mathrm{bin}})\%$ of planet detections, where $f_{\mathrm{bin}}$ is the binary fraction, with the majority of these failures occurring for host stars with mass $\lesssim$0.3$M_{\odot }$.

15 pages, 8 figures, submitted to ApJ. For a brief video explaining the key results of this paper, please visit: http://youtu.be/PFgFrEj0cMU

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Cited by in corpus (1)

• Detecting binarity of GW150914-like lenses in gravitational microlensing events