WFIRST Could Detect Kuiper Objects as Small as 7.5 km Diameter

WFIRST Ultra-Precise Astrometry I: Kuiper Belt Objects

Author:

Gould

Abstract:

I show that the WFIRST microlensing survey will enable detection and precision orbit determination of Kuiper Belt Objects (KBOs) down to H_vega=28.2 over an effective area of about 17 square deg. Typical fractional period errors will be ~1.5% X 10^{0.4(H-28.2)} with similar errors in other parameters for roughly 5000 KBOs. Binary companions to detected KBOs can be detected to even fainter limits, H_vega=29, corresponding to R~31 and effective diameters D~7.5 km. This will provide an unprecedented probe of orbital resonance and KBO mass measurements.