Search for sub-kilometre trans-Neptunian objects using CoRoT asteroseismology data

Abstract

We present the search for sub-kilometre trans-Neptunian objects (TNOs) by re-examining the CoRoT (Convection Rotation and Planetary Transits) asteroseismology observations. The total observation time employed in this work is about 144 000 star hours with signal-to-noise ratio larger than 1000 computed on 30-s intervals. 13 Possible Occultation Events (POEs) were found from the deviation method. These detections gives a density in the ecliptic sky plane of TNOs larger than 400-m radius of N(R > 400 m)=1.4^{+4.2} _{-0.7} × 10⁷ deg^{-2}. The fit of the density of TNOs with the believed break r_break = 45 km provides a power-law size distribution index q larger than 3.5. This value is consistent with the detection of two potential events from Hubble Space Telescope (HST)/Fine Guidance Sensor (FGS) observations that found q = 3.8 ± 0.2. However, fitting the 13 POEs with the HST/FGS result alone gives a power-law size distribution index of q = 4.5 ± 0.2 in the size range of 0.2-2.0 km. This value is then compared with evolution models of the Kuiper belt.