Planetary Radar at Arecibo Observatory

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Click on an object in the solar system or choose from the list at left to learn more


What Asteroids Are Visible NOW?

Recently Observed Asteroids:

(192642) 1999 RD32 - Found to be a contact binary with multi-kilometer-diameter components
2201 Oljato
2012 DH54
5 Astraea
2012 DW60
2012 DH4
2012 EO8
2010 SV3
2012 BT23
2012 FZ23
2004 FG11 - Found to be a binary system (with the second smallest primary component as yet found by radar)!
2003 WH166
(141018) 2001 WC47
(29075) 1950 DA
2012 HL
2012 HM8
1994 NK
2010 KX7
2001 SZ269

Upcoming Radar Targets:

Asteroid Dates Expected
Results		 IRTF
Target?		 H mag Request Optical
Astrometry?		 Request Optical
Lightcurve?		 Request Optical
Characterization?		 Notes
(29075) 1950 DA Apr 29-01 Astrometry 17.0 Potential impactor
Previously observed
2010 KX7 Apr 30-03 Imaging 22.0 Period unknown
2012 GP1 Apr 30-02 Astrometry 26.2 Period unknown
1998 HE3 May 09-11 High-res Imaging 21.7 Y? Period unknown
2007 LE Jun 01-03 High-res Imaging 19.1 Y (10 arcsec) Y Period unknown
2001 CQ36 Jun 12-14 Imaging 22.7 Y (50 arcsec) Period unknown
2005 GO21 Jun 21-26 High-res Imaging 16.4 Y (20 arcsec) Y Y Period unknown
(144411) 2004 EW9 Jul 11-20 High-res Imaging 16.6
(153958) 2002 AM31 Jul 12-16 High-res Imaging Y 18.1 Y (20 arcsec) Y Y Period unknown
2003 KU2 Jul 21-23 Imaging Y 17.7 Y (80 arcsec) Y Y Period unknown
(1685) Toro Jul 22-23 Astrometry Y 14.2 Yarkovsky candidate
(2062) Aten Jul 24-25 Astrometry 16.8 Yarkovsky candidate

Requests for Optical Observations:

Astrometry: optical astrometry is requested for objects with plane-of-sky pointing uncertainties of 10 arcseconds or more.
Lightcurves: optical lightcurves and period estimates are requested for objects that will produce high-resolution images (i.e., possible shape models) and for targets of IRTF thermal observations.
Characterization: optical characterization refers to spectra and colors, which are most important for targets of IRTF thermal observations and for completeness for the strongest radar targets.

Arecibo Observatory Discovers a near-Earth triple asteroid system

The Arecibo Planetary Radar discovered that near-Earth Asteroid 2001 SN263 is a triple asteroid system.

Division of Planetary Sciences resolution on the Arecibo planetary radar

The Division of Planetary Sciences of the American Astronomical Society unanimously passed a resolution on the status of Arecibo radar.

"One-page" description of the Arecibo planetary radar

We have prepared a one-page informational flyer that may be useful as a handout to interested parties.

Asteroid Dynamics Workshop

The Arecibo Asteroid Dynamics Workshop was held 2003 Feb 2-4 at Arecibo Observatory. Click Here for the workshop web site.

First Near-Earth Asteroid Satellite System: 2000 DP107

2000 DP107 was the first asteroid identified by radar as a binary system. The primary is roughly spherical with a diameter of 800 meters (a half mile) and the smaller secondary, which orbits it in 1.8 days, is about 300 meters (1000 feet).

The primary has a low density of 1.7 and is assumed to be a "rubble pile" of rocks and voids. It is spinning at a rate near the breakup point for strengthless bodies, and therefore any slight gravitational disturbance can pull it apart. Probably an encounter with the gravity of a planet created the binary by pulling apart the primary.

Four more binary systems have been discovered by radar among the near-Earth asteroids, making one of every 6 a binary.

Binary asteroid 2000 DP107


A composite of images of 2000 DP107 obtained at Arecibo Observatory in September-October 2000. The frame is 5.8 km vertically, with distance from the observer increasing downward, and 12.2 Hz horizontally, with Doppler frequency or line-of-sight velocity increasing to the right. Rotation and revolution are counterclockwise.

The illuminated front of a roughly spherical primary is visible, as well as a secondary at different phases of the orbital cycle. In this image the secondary appears much smaller than the primary because its spin rate is lower. The actual size ratio is 8 to 3. Also, the orbit appears elliptical in this image but it is circular in space.

More on 2000 DP107:  
Margot web page ,  Klet Observatory optical data ,  IAU Circular #7496 ,  IAU Circular #7503 ,  Table from NeoDys,  Orbit diagram from JPL  

Last modified by Alice 23 apr 02