739 observed NEAs and new 2-4 m survey statistics within the EURONEAR network
O. Vaduvescu et al.
Planet. Space Sci., 85, 299-311 (2013)
Abstract:
We report follow-up observations of 477 program Near-Earth Asteroids (NEAs)
using nine telescopes of the EURONEAR network having apertures between 0.3
and 4.2 m. Adding these NEAs to our previous results we now count 739 program
NEAs followed-up by the EURONEAR network since 2006. The targets were
selected using EURONEAR planning tools focusing on high priority objects.
Analyzing the resulting orbital improvements suggests astrometric follow-up
is most important days to weeks after discovery, with recovery at a new
opposition also valuable. Additionally we observed 40 survey fields spanning
three nights covering 11 square degrees near opposition, using the Wide Field
Camera on the 2.5 m Isaac Newton Telescope (INT), resulting in 104 discovered
main belt asteroids (MBAs) and another 626 unknown one-night objects. These
fields, plus program NEA fields from the INT and from the wide field MOSAIC
II camera on the Blanco 4 m telescope, generated around 12000 observations of
2000 minor planets (mostly MBAs) observed in 34 square degrees. We identify
Near Earth Object (NEO) candidates among the unknown (single night) objects
using three selection criteria. Testing these criteria on the (known) program
NEAs shows the best selection methods are our epsilon-miu model which checks
solar elongation and sky motion and the MPC's NEO rating tool. Our new data
show that on average 0.5 NEO candidates per square degree should be
observable in a 2 m-class survey (in agreement with past results), while an
average of 2.7 NEO candidates per square degree should be observable in a
4 m-class survey (although our Blanco statistics were affected by clouds). At
opposition just over 100 MBAs (1.6 unknown to every 1 known) per square
degree are detectable to R=22 in a 2 m survey based on the INT data, while
our two best ecliptic Blanco fields away from opposition lead to 135 MBAs (2
unknown to every 1 known) to R=23.
Full Paper (including Appendix) from astro-ph
EURONEAR website