Screen shot from A/CC's prototype interactive sky chart viewer. Objects in white are outside ten LD at the date and time shown, green inside ten LD, yellow inside Earth's Hill Sphere (except the Sun, of course), orange inside two LD, and red inside one LD of Earth -- all from JPL SSD Horizons data.
--> See more screen shots and with animation.
Today's Traffic: Four objects are reported flying within ten lunar distances (LD)1 of Earth on Thursday, January 26th. 2012 BW13 is inside Earth's Hill sphere, moving from 1.85 to 2.63 LD. It is coming its closest to Earth today on this passage, reaching 1.73 LD at 0602 UTC, and also coming its closest to the Moon, reaching 2.55 LD at 0933 UTC. 2012 BS1 moves from 5.21 to 6.90 LD and 2012 BD14 from 9.83 to 8.57 LD, while 2012 BY1 departs from within ten LD today.
One object is known to be approaching to within ten LD between now and early March. 2011 CP4 will come inside ten LD on February 22nd.
Thirteen objects recently flew past Earth at less than ten LD and remain of continuing active interest. See their details below.
This report was refreshed at 1341 UTC. No DOU MPEC has been posted yet and no explanation, but things could get busy later today with lots of objects moving through the discovery confirmation process.
Note: Watch A/CC's new, separate "Traffic Report" in "The Tracking News" for quicker updates and direct links to the observing record for close passers. (During 24-27 January, it may at times be the only traffic report to update.)
1. Ten lunar distances: A "lunar distance" (LD) is the average distance between Earth and Moon (about 384,400 km., the same as 238,855 miles or nearly ten [9.59] times around Earth's equator). Ten lunar distances has no special astronomical importance but is a useful arbitrary "bubble" within which to organize this report. An approach by a small Solar-System body starts to become interesting at less than four LD out from Earth as it encounters our planet's "Hill sphere" (distance indicated by the blue line in this illustration at about 3.9 LD). This is a region within which Earth's gravitational influence can change the orbital paths of passing objects. The Moon also has a Hill sphere, outlined here as a gray circle. (The Earth and Moon are not shown to scale.) The "Earth-Moon system" is generally defined as that region of space within a radius of one lunar distance from Earth, so an object can pass very close to the Moon yet not be described as coming "inside" the E-M system.
2. Data credit: All data on this page derived from orbit solutions comes from the NASA JPL Solar System Dynamics (SSD) Group through its Horizons system. All information about optical observations comes from the IAU Minor Planet Center (MPC) and info about radar observations comes from JPL SSD. NASA, JPL, and the MPC are not associated with this page or A/CC, and responsibility for the interpretation of this information and its use here rests entirely with A/CC. Important note: Approach times presented here as to-the-minute may have unstated uncertainties of a few minutes, or many minutes or even hours for objects with old or very short observation spans, which is significant because the Earth moves through its own diameter in about six minutes. Thus actual encounter distances may vary, occasionally by as much as ten lunar distances. See JPL's Close Approach Tables for nominal vs. minimum possible passage distances and times and for their note about uncertainties.
3. Size estimates: Object diameters are rough approximations derived by standard formula from H, an object's "absolute magnitude" (brightness), where higher numbers represent dimmer (thus usually smaller) objects.
| 2012 BS1 - departing | |
| Approximate diameter: | 7 meters (H=28.366) |
| Closest Earth approach: | 3.12 LD at 2129 UTC on 23 Jan. |
| Inside Earth's Hill sphere: | 22 Jan. until yesterday |
| Inside ten LD of Earth: | 19 to 28 Jan. |
| Data based on: | JPL SSD orbit solution #3 downloaded 23 Jan. based on 19 observations spanning 3 days |
| Optical observation: | observed from 3 locations during 3.1848 days first observed at 0655 UTC on 18 Jan. by the Mt. Lemmon Survey last observed at 1121 UTC on 21 Jan. by the Spacewatch 1.8m telescope |
| Links: | JPL Small-Body Database NEODyS 2012BS1 Close Approaches |
| 2012 BY1 - departing | |
| Approximate diameter: | 24 meters (H=25.788) |
| Closest Earth approach: | 2.04 LD at 0847 UTC on 24 Jan. |
| Inside Earth's Hill sphere: | 23 Jan. until yesterday |
| Inside ten LD of Earth: | 22 Jan. until today |
| Closest Moon approach: | 2.34 LD at 1330 UTC 24 Jan. |
| Data based on: | JPL SSD orbit solution #5 downloaded yesterday based on 43 observations spanning 6 days |
| Optical observation: | observed from 5 locations during 5.7181 days first observed at 0921 UTC on 18 Jan. by the Mt. Lemmon Survey last observed at 0235 UTC on 24 Jan. by Great Shefford Obs. |
| Note: | risk |
| Links: | JPL Small-Body Database NEODyS 2012BY1 Close Approaches |
| 2012 BW13 - departing | |
| Approximate diameter: | 12 meters (H=27.166) |
| Closest Earth approach: | 1.73 LD at 0602 UTC today |
| Inside Earth's Hill sphere: | 24 Jan. until tomorrow |
| Inside ten LD of Earth: | 22 to 29 Jan. |
| Closest Moon approach: | 2.55 LD at 0933 UTC today |
| Data based on: | JPL SSD orbit solution #5 downloaded yesterday based on 27 observations spanning 5 days |
| Optical observation: | observed from 4 locations during 5.6869 days first observed at 0458 UTC on 19 Jan. by the Mt. Lemmon Survey last observed at 2127 UTC on 24 Jan. by Paus Obs. |
| Note: | risk |
| Links: | JPL Small-Body Database NEODyS 2012BW13 Close Approaches |
| 2012 BD14 - approaching | |
| Approximate diameter: | 15 meters (H=26.743) |
| Closest Earth approach: | 5.78 LD at 2209 UTC on 30 Jan. |
| Inside ten LD of Earth: | yesterday until 4 Feb. |
| Data based on: | JPL SSD orbit solution #4 downloaded yesterday based on 29 observations spanning 4 days |
| Optical observation: | observed from 4 locations during 3.8960 days first observed at 0712 UTC on 20 Jan. by the Mt. Lemmon Survey last observed at 0442 UTC on 24 Jan. by Sandlot Obs. |
| Links: | JPL Small-Body Database NEODyS 2012BD14 Close Approaches |
| 2011 CP4 - approaching | |
| Approximate diameter: | 199 meters (H=21.156) |
| Closest Earth approach: | 9.05 LD at 1407 UTC on 23 Feb. - Note: JPL reports an approach uncertainty of 17 minutes. |
| Inside ten LD of Earth: | 22 to 24 Feb. |
| Data based on: | JPL SSD orbit solution #14 downloaded 23 Jan. (dated 14 Sept. 2011) based on 47 observations spanning 30 days |
| Optical observation: | none recent |
| Note: | radar target |
| Links: |
|
These objects either departed from ten LD during the last week or were reported observed.
| 2012 AP10 - departed | |
| Approximate diameter: | 18 meters (H=26.42) |
| Closest Earth approach: | 1.06 LD at 2027 UTC on 30 Dec. - Note: JPL reports an approach uncertainty of 5 minutes. |
| Inside Earth's Hill sphere: | 26 Dec. until 4 Jan. |
| Inside ten LD of Earth: | 18 Dec. until 11 Jan. |
| Closest Moon approach: | 1.48 LD at 2228 UTC 31 Dec. |
| Data based on: | JPL SSD orbit solution #9 downloaded 20 Jan. based on 63 observations spanning 9 days |
| Optical observation: | observed from 8 locations during 9.1249 days first observed at 0200 UTC on 11 Jan. by the Mt. Lemmon Survey last observed at 0500 UTC on 20 Jan. by the Spacewatch 1.8m telescope |
| Note: | risk |
| Links: | JPL Small-Body Database NEODyS 2012AP10 Close Approaches |
| 2012 BC14 - departed | |
| Approximate diameter: | 38 meters (H=24.764) |
| Closest Earth approach: | 7.71 LD at 0451 UTC on 1 Jan. - Note: JPL reports an approach uncertainty of 16 hours and 1 minute. |
| Inside ten LD of Earth: | 29 Dec. until 3 Jan. |
| Data based on: | JPL SSD orbit solution #2 downloaded 23 Jan. based on 20 observations spanning 1 day |
| Optical observation: | observed from 3 locations during 1.2639 days first observed at 0457 UTC on 20 Jan. by the Mt. Lemmon Survey last observed at 1117 UTC on 21 Jan. by the Mt. Lemmon Survey |
| Links: | JPL Small-Body Database NEODyS 2012BC14 Close Approaches |
| 2012 BO11 - departed | |
| Approximate diameter: | 24 meters (H=25.777) |
| Closest Earth approach: | 3.95 LD at 1816 UTC on 13 Jan. |
| Inside ten LD of Earth: | 8 to 18 Jan. |
| Data based on: | JPL SSD orbit solution #3 downloaded 23 Jan. based on 24 observations spanning 3 days |
| Optical observation: | observed from 3 locations during 2.7899 days first observed at 1148 UTC on 19 Jan. by the Catalina Sky Survey last observed at 0646 UTC on 22 Jan. by Robert Holmes via Cerro Tololo Inter-American Obs. |
| Note: | risk |
| Links: | JPL Small-Body Database NEODyS 2012BO11 Close Approaches |
| 2012 BU1 - departed | |
| Approximate diameter: | 10 meters (H=27.688) |
| Closest Earth approach: | 3.64 LD at 1152 UTC on 14 Jan. |
| Inside Earth's Hill sphere: | 13 to 15 Jan. |
| Inside ten LD of Earth: | 10 to 18 Jan. |
| Data based on: | JPL SSD orbit solution #3 downloaded 23 Jan. based on 28 observations spanning 3 days |
| Optical observation: | observed from 3 locations during 3.0948 days first observed at 0741 UTC on 18 Jan. by the Mt. Lemmon Survey last observed at 0958 UTC on 21 Jan. by the Spacewatch 1.8m telescope |
| Note: | risk |
| Links: | JPL Small-Body Database NEODyS 2012BU1 Close Approaches |
| 2012 BX1 - departed | |
| Approximate diameter: | 37 meters (H=24.786) |
| Closest Earth approach: | 8.06 LD at 0052 UTC on 15 Jan. |
| Inside ten LD of Earth: | 12 to 17 Jan. |
| Data based on: | JPL SSD orbit solution #2 downloaded yesterday based on 36 observations spanning 1 day |
| Optical observation: | observed from 6 locations during 24.269 hours first observed at 0841 UTC on 18 Jan. by the Catalina Sky Survey last observed at 0857 UTC on 19 Jan. by the Catalina Sky Survey |
| Links: | JPL Small-Body Database NEODyS 2012BX1 Close Approaches |
| 2012 BT1 - departed | |
| Approximate diameter: | 12 meters (H=27.332) |
| Closest Earth approach: | 9.35 LD at 0917 UTC on 15 Jan. - Note: JPL reports an approach uncertainty of 4 minutes. |
| Inside ten LD of Earth: | 12 to 17 Jan. |
| Data based on: | JPL SSD orbit solution #1 downloaded 19 Jan. based on 19 observations spanning 1 day |
| Optical observation: | observed from 3 locations during 24.497 hours first observed at 0740 UTC on 18 Jan. by the Mt. Lemmon Survey last observed at 0810 UTC on 19 Jan. by the Mt. Lemmon Survey |
| Links: | JPL Small-Body Database NEODyS 2012BT1 Close Approaches |
| 2012 BK14 - departed | |
| Approximate diameter: | 11 meters (H=27.492) |
| Closest Earth approach: | 4.25 LD at 0921 UTC on 15 Jan. - Note: JPL reports an approach uncertainty of 8 hours and 36 minutes. |
| Inside ten LD of Earth: | 8 to 22 Jan. |
| Data based on: | JPL SSD orbit solution #1 downloaded 21 Jan. based on 11 observations |
| Optical observation: | observed from 2 locations during 3.564 hours first observed at 0736 UTC on 21 Jan. by the Catalina Sky Survey last observed at 1110 UTC on 21 Jan. by the Spacewatch 1.8m telescope |
| Note: | risk |
| Links: | JPL Small-Body Database NEODyS 2012BK14 Close Approaches |
| 2012 AQ10 - departed | |
| Approximate diameter: | 15 meters (H=26.724) |
| Closest Earth approach: | 2.24 LD at 1252 UTC on 16 Jan. |
| Inside Earth's Hill sphere: | 14 to 18 Jan. |
| Inside ten LD of Earth: | 10 to 22 Jan. |
| Closest Moon approach: | 2.08 LD at 2134 UTC 16 Jan. |
| Data based on: | JPL SSD orbit solution #5 downloaded 19 Jan. based on 63 observations spanning 4 days |
| Optical observation: | observed from 13 locations during 3.9744 days first observed at 0639 UTC on 13 Jan. by the Catalina Sky Survey last observed at 0602 UTC on 17 Jan. by Robert Holmes via Cerro Tololo Inter-American Obs. |
| Links: | JPL Small-Body Database NEODyS 2012AQ10 Close Approaches |
| 2011 YH40 - departed | |
| Approximate diameter: | 86 meters (H=22.979) |
| Closest Earth approach: | 5.36 LD at 1736 UTC on 16 Jan. |
| Inside ten LD of Earth: | 12 to 20 Jan. |
| Data based on: | JPL SSD orbit solution #27 downloaded 23 Jan. based on 389 observations spanning 2011-2012 including radar observation |
| Optical observation: | observed from 22 locations during 23.9585 days first observed at 1000 UTC on 29 Dec. by the Catalina Sky Survey last observed at 0900 UTC on 22 Jan. by Robert Holmes via Cerro Tololo Inter-American Obs. |
| Radar observation: | observed 3 times from one location during 0.0347 days first observed at 0430 UTC 15 Jan. by Goldstone DSS-14 70m antenna last observed at 0520 UTC 15 Jan. by Goldstone DSS-14 70m antenna |
| Links: |
|
| 2012 BZ13 - departed | |
| Approximate diameter: | 23 meters (H=25.866) |
| Closest Earth approach: | 9.10 LD at 2302 UTC on 18 Jan. |
| Inside ten LD of Earth: | 16 to 20 Jan. |
| Data based on: | JPL SSD orbit solution #3 downloaded yesterday based on 31 observations spanning 4 days |
| Optical observation: | observed from 5 locations during 3.9337 days first observed at 0441 UTC on 20 Jan. by the Catalina Sky Survey last observed at 0306 UTC on 24 Jan. by Robert Holmes via Cerro Tololo Inter-American Obs. |
| Links: | JPL Small-Body Database NEODyS 2012BZ13 Close Approaches |
| 2012 BL14 - departed | |
| Approximate diameter: | 8 meters (H=28.172) |
| Closest Earth approach: | 1.20 LD at 0033 UTC on 20 Jan. - Note: JPL reports an approach uncertainty of 14 minutes. |
| Inside Earth's Hill sphere: | 19 to 20 Jan. |
| Inside ten LD of Earth: | 17 to 22 Jan. |
| Closest Moon approach: | 1.86 LD at 2107 UTC 19 Jan. |
| Data based on: | JPL SSD orbit solution #1 downloaded 21 Jan. based on 17 observations |
| Optical observation: | observed from one location during 2.851 hours first observed at 0858 UTC on 21 Jan. by the Mt. Lemmon Survey last observed at 1150 UTC on 21 Jan. by the Mt. Lemmon Survey |
| Note: | risk |
| Links: | JPL Small-Body Database NEODyS 2012BL14 Close Approaches |
| 2012 BV1 - departed intruder | |
| Approximate diameter: | 2 meters (H=30.982) |
| Closest Earth approach: | 0.83 LD at 0713 UTC on 20 Jan. |
| Inside Earth-Moon system: | 0015-1411 UTC on 20 Jan. |
| Inside Earth's Hill sphere: | 18 to 22 Jan. |
| Inside ten LD of Earth: | 15 Jan. until yesterday |
| Closest Moon approach: | 0.55 LD at 1747 UTC 20 Jan. |
| Inside one LD of Moon: | 0656 UTC on 20 Jan. until 0433 UTC on 21 Jan. |
| Data based on: | JPL SSD orbit solution #1 downloaded 19 Jan. based on 18 observations spanning 1 day |
| Optical observation: | observed from 2 locations during 1.1223 days first observed at 0820 UTC on 18 Jan. by the Mt. Lemmon Survey last observed at 1116 UTC on 19 Jan. by the Mt. Lemmon Survey |
| Links: | JPL Small-Body Database NEODyS 2012BV1 Close Approaches |
| 2012 BF27 - departed | |
| Approximate diameter: | 20 meters (H=26.093) |
| Closest Earth approach: | 1.90 LD at 2156 UTC on 20 Jan. - Note: JPL reports an approach uncertainty of 7 minutes. |
| Inside Earth's Hill sphere: | 19 to 22 Jan. |
| Inside ten LD of Earth: | 17 to 24 Jan. |
| Closest Moon approach: | 1.13 LD at 1734 UTC 20 Jan. |
| Data based on: | JPL SSD orbit solution #1 downloaded 24 Jan. based on 28 observations spanning 1 day |
| Optical observation: | observed from 6 locations during 16.003 hours first observed at 0805 UTC on 23 Jan. by the Catalina Sky Survey last observed at 0005 UTC on 24 Jan. by Schiaparelli Obs. |
| Note: | risk |
| Links: | JPL Small-Body Database NEODyS 2012BF27 Close Approaches |