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The Arecibo Observatory planetary radar is the world's most powerful instrument for post-discovery characterization and orbital refinement of near-Earth objects. Arecibo radar observations are critical for identifying asteroids that might be on collision course with Earth and, if necessary, preventing a collision. Radar can provide detailed physical characterizations of NEAs:

• If a small body is on course for an Earth collision in this century, Arecibo radar measurements could show this, and would dramatically reduce the difficulty and cost of any mitigation effort by defining the object's size, shape, mass, spin state, and orbit, and by revealing if it is one body or a two-body system.
• Radar investigations of many NEAs are roughly equivalent, in their science content, to space flyby missions, but have a much lower cost (five orders of magnitude)

Radar is invaluable in determining the orbits of potentially hazardous NEAs.

• Range-Doppler radar measurements complement optical observations by providing line- of-sight positional astrometry with precision as fine as 10 m in range and 1 mm/s in velocity, with a fractional precision 100 to 1000 times finer than that of typical optical measurements.
• Radar data increase the average interval of predictability (relative to optical-only orbit solutions) by up to 370 years and can provide warnings of impact during the initial discovery period, whereas two widely separated observations are needed for optical-only orbits.
• Radar data can quickly eliminate collision false alarms caused by optical-only data.

These unique capabilities of radar are critically important as we work towards the 2005 Congressional mandate of detecting and characterizing 90% of NEAs down to 140 m in size.

The Solar System Studies group is a department of the Arecibo Observatory, which is an NSF facility operated under cooperative agreement by SRI International, Universities Space Research Association (USRA), and la Universidad Metropolitana (UMET). The Arecibo Observatory radar is funded through the NASA Near-Earth Objects Observations program and scientific staff in the department are USRA employees.

For more information, follow us on Twitter at Follow @AreciboRadar and Follow @NAICobservatory !

All detections in 2016 - most recent first

For media inquiries, contact our press officer Ruth Torres, rutorres at suagm.edu

2015 XA379
2001 BB16
(438661) 2008 EP6
2015 WE2
(85990) 1999 JV6
(162385) 2000 BM19
(337866) 2001 WL15 - first detected in Dec 2015

All detections in 2015

Asteroid	Dates	Expected Results	IRTF Target?	H mag	Request Optical Astrometry?	Request Optical Lightcurve?	Request Optical Characterization?	Notes
(363599) 2004 FG11	Apr 05-17	Imaging		21.0		Y	Y	Binary, PHA, period unknown
252 P/LINEAR	Apr 10-18	Imaging				Y	Y	COMET!
2003 KO2	Apr 25-01	High-res Imaging		20.2		Y	Y	PHA, period unknown
(388945) 2008 TZ3	Apr 26	Imaging		20.4		Y		PHA, period unknown
2014 US115	Apr 30	Imaging		24.6	6 deg!			Period unknown
2009 DL46	May 20-23	High-res Imaging	Y	21.5		Y	Y	PHA, period unknown

Astrometry: optical astrometry is specifically requested for objects with plane-of-sky pointing uncertainties of tens of arcseconds or more. Optical observers are asked to submit astrometry to the Minor Planet Center as soon as possible after observations.

Lightcurves: optical lightcurves and period estimates are specifically requested for objects that will produce high-resolution images (i.e., possible shape models), for targets of IRTF thermal-infrared observations, for candidate binary asteroids, and for potential human-exploration targets. Lightcurve observers are asked to relay period estimates to the radar team to help with the planning of radar observations. During the analysis and modeling process, the radar team may request to use available lightcurve data.

Characterization: optical characterization refers to spectra and colors, which are most important for targets of IRTF thermal observations, for completeness of the strongest radar targets, for candidate binary asteroids, and for potential human-exploration targets. Optical observers are asked to relay probable spectral-class information to the radar team to compare with characteristics suggested by radar.