Contents  on 16 December '18

Asteroid/Comet Connection (A/CC) Resources:

The latest A/CC news is available via framed access, RSS news feed RSS news feed, or redirection.

Navigation tips: Use the << and >> arrows on the menus for each regular section (Observers, Risks, etc.) to move to the previous and next day's news for that section. Use the Index menu item to access specific days through a calendar interface. To keep track of what's new each day, watch the Chronology section.

Traffic Report  on 16 December '18

Twelve objects reported inside ten LD

Twelve small visitors are being tracked within ten lunar distances (LD) of Earth today. The two nearest are risk-listed 2018 VO9, outbound from 2.64 to 2.79 LD, and 2018 XS4, which comes its closest to our planet on this passage, reaching 2.76 LD at 0731 UTC.

Neighborhood Traffic - sorted by Earth passage distance, grouped by 1.0, 2.41, 5.0 & 10.0 LD boundaries
Earth passage I D ~Size Distance today  Inside ten LD Notes
0.09 LD Dec. 2 2018 WV1 3 m  6.06 to 6.47 LD Nov. 8 - Dec. 25 intruder, NHATS target
1.25 LD Dec. 10 2018 XX3 4 m  5.44 to 6.44 LD Nov. 30 - Dec. 20 NHATS target, risk
1.6   LD Dec. 21* 2018 XC4 19 m  8.2 from 9.9 LD yesterday - Dec. 27 EPU +/- 38 mins.*, NHATS target
2.42 LD Dec. 12 2018 XL1 14 m  5.70 to 6.97 LD Dec. 5 - 19 NHATS target
2.62 LD yesterday 2018 VO9 14 m  2.64 to 2.79 LD Nov. 29 - Dec. 31 NHATS target, risk
2.72 LD yesterday 2018 XG4 11 m  3.18 to 4.34 LD Dec. 9 - 20
2.76 LD today 2018 XS4 30 m  2.76 LD Dec. 11 - 21 Earth closest at 0731 UTC
3.49 LD Dec. 11 2013 VX4 62 m  7.34 to 8.67 LD Dec. 5 - 17 = 2018 XM4 - MPEC
3.92 LD Dec. 2 2018 TG6 12 m  5.40 to 5.60 LD Oct. 30 - Jan. 5 NHATS target
5.32 LD tomorrow 2018 XR4 15 m  5.86 from 7.32 LD Dec. 14 - 21 risk
5.58 LD Dec. 13 2018 XJ1 18 m  6.81 to 7.71 LD Dec. 7 - 19
6.93 LD Dec. 14 2018 XB5 48 m  7.99 to 10.14 LD Dec. 12 - 16 NEW, exits ten LD - MPEC

This report was generated at 1940 UTC with the discovery of outbound 2018 XB5 (MPEC) and the recovery of 2013 VX4 (MPEC), originally designated as new discovery 2018 XM4, which came to 3.49 LD instead of 4.09 from the calculation based on limited 2013 astrometry, and did so almost two days later.

Approaching - sorted by 10-LD bubble entry date
Earth passage I D ~Size Distance today  Inside ten LD Notes
7.36 LD Dec. 22 163899 2003 SD220 1.17 km  10.18 from 11.19 LD tomorrow - Dec. 26 radar/NHATS target
5.3   LD Dec. 26* 2018 XE4 17 m  21.5 from 23.5 LD Dec. 22 - 30 EPU +/- 3.33 hours*
7.8   LD Jan. 6* 2018 XO4 29 m  19.7 from 20.4 LD Dec. 30 - Jan. 13 EPU +/- 3.18 hours*, NHATS target
7.3   LD Jan. 9* 2013 YM2 19 m  23.9 from 24.8 LD Jan. 2 - 16 EPU +/- 3.75 days*, NHATS target
* EPU = Earth passage uncertainty



Notes: Ten times the distance to the Moon (ten LD) has no astronomical importance but is a useful boundary for reporting about transient natural objects that approach our planet's gravitational sphere of influence (SOI), which has a radius of about 2.41 LD from Earth's center. This puts a focus on some of the most important and very best NEO observation work, representative of the much larger NEO discovery and tracking effort. Object temporal distances are derived by A/CC from JPL Horizons data. "LD*" indicates some uncertainty in object passage time and distance. See also current sky chart and object details (alt-details), ephemerides, and today's timeline.

Radar Astrometry  on 16 December '18

Radar observation of one object

The JPL Solar System Dynamics Group Radar Astrometry database has added or updated the following small-body radar observing work:


Data update noted at 2000 UTC when the database was dated 16 Dec.



Photometry and some astrometry is needed for upcoming radar targets. See Arecibo and Goldstone schedules.

NEOCP Activity  on 16 December '18

The MPC's NEO Confirmation Page has 61 listings

When last checked at 2358 UTC today, the Minor Planet Center's Near Earth Object discovery Confirmation Page (NEOCP) had 61 objects listed. Of these, 28 were "one nighters." So far The Tracking News has counted a total of 72 listings on the NEOCP today.

To learn how observers use the NEOCP, see the Practical guide on how to observe NEOCP object at Suno Observatory by Birtwhistle et al.

New MPECs  on 16 December '18

Minor Planet Electronic Circulars

As of last check at 2358 UTC, there have been twelve MPECs posted today from the International Astronomical Union's Minor Planet Center in Cambridge, Massachusetts.


<< DOU on 16 Dec. '18 >>  MPEC 2018-Y12 - "13:04 UT" - Daily Orbit Update


MPEC 2018-Y11 - "12:54 UT" - 2018 DO4


MPEC 2018-Y10 - "04:49 UT" - 2018 XD5


MPEC 2018-Y09 - "04:46 UT" - 2018 XC5


MPEC 2018-Y08 - "04:42 UT" - 2018 XB5


MPEC 2018-Y07 - "04:38 UT" - 2018 XA5


MPEC 2018-Y06 - "04:34 UT" - 2018 XZ4


MPEC 2018-Y05 - "04:30 UT" - 2018 XY4


MPEC 2018-Y04 - "04:26 UT" - 2018 XX4


MPEC 2018-Y03 - "04:22 UT" - 2018 XW4


MPEC 2018-Y02 - "03:42 UT" - 2002 XQ90


MPEC 2018-Y01 - "00:25 UT" - 2013 VX4 = 2018 XM4

Id. R. Matson

Observers  on 16 December '18

A total of 33 observers appear in today's MPECs.

CodeObserver / observatory
T08ATLAS Mauna Loa in Hawaii, 2 in MPECs 2018-Y02 & 2018-Y08 -- 2018 XB5, 2002 XQ90
C77Bernezzo Obs. in Italy, 2 in MPECs 2018-Y02 & 2018-Y06 -- 2018 XZ4, 2002 XQ90
160Castelmartini Obs. in Italy, 3 in MPECs 2018-Y02, 2018-Y06 & 2018-Y08 -- 2018 XZ4, 2018 XB5, 2002 XQ90
703Catalina Sky Survey (CSS) in Arizona, 2 in MPECs 2018-Y02 & 2018-Y06 -- 2018 XZ4, 2002 XQ90
K51Celado Obs. in Italy, 1 in MPEC 2018-Y02 -- 2002 XQ90
Z99Clixby Obs. in England, 1 in MPEC 2018-Y02 -- 2002 XQ90
595Farra d'Isonzo Obs. in Italy, 3 in MPECs 2018-Y02, 2018-Y06 & 2018-Y08 -- 2018 XZ4, 2018 XB5, 2002 XQ90
157Frasso Sabino Obs. in Italy, 1 in MPEC 2018-Y11 -- 2018 DO4
203GiaGa Obs. in Italy, 2 in MPECs 2018-Y06 & 2018-Y08 -- 2018 XZ4, 2018 XB5
253Goldstone DSS-14 70m antenna in southern California, 1 in radar -- 163899
J95Great Shefford Obs. in England, 3 in MPECs 2018-Y02, 2018-Y06 & 2018-Y08 -- 2018 XZ4, 2018 XB5, 2002 XQ90
H15ISON New Mexico Obs. in New Mexico, 2 in MPECs 2018-Y06 & 2018-Y08 -- 2018 XZ4, 2018 XB5
U69"M. Suzuki in Japan via iTelescope Obs. Auberry in northern California, 2 in MPECs 2018-Y02 & 2018-Y08 -- 2018 XB5, 2002 XQ90
H06iTelescope Obs. Mayhill in New Mexico, 1 in MPEC 2018-Y02 -- 2002 XQ90
P93JAXA Space Tracking & Communications Center (JAXA STCC) in Japan, 2 in MPECs 2018-Y02 & 2018-Y06 -- 2018 XZ4, 2002 XQ90
K38M57 Obs. in Italy, 3 in MPECs 2018-Y02, 2018-Y06 & 2018-Y08 -- 2018 XZ4, 2018 XB5, 2002 XQ90
H01Magdalena Ridge Obs. (MRO) in New Mexico, 2 in MPECs 2018-Y02 & 2018-Y06 -- 2018 XZ4, 2002 XQ90
568^R. Wainscoat on Mauna Kea in Hawaii, 4 in MPECs 2018-Y05, 2018-Y07, 2018-Y09 & 2018-Y10 -- 2018 XY4, 2018 XD5, 2018 XC5, 2018 XA5
568_Marco Micheli on Mauna Kea in Hawaii, 1 in MPEC 2018-Y11 -- 2018 DO4
G96Mt. Lemmon Survey (MLS) in Arizona, 3 in MPECs 2018-Y03, 2018-Y04 & 2018-Y06 -- 2018 XZ4, 2018 XX4, 2018 XW4
J69North Obs. in England, 2 in MPECs 2018-Y02 & 2018-Y06 -- 2018 XZ4, 2002 XQ90
Z80Northolt Branch Obs. in England, 3 in MPECs 2018-Y02, 2018-Y06 & 2018-Y08 -- 2018 XZ4, 2018 XB5, 2002 XQ90
F51Pan-STARRS 1 (PS1) in Hawaii, 19 in MPECs 2018-Y02, 2018-Y05, 2018-Y07, 2018-Y09, 2018-Y10 & 2018-Y12 -- 2018 XY4, 2018 XD5, 2018 XC5, 2018 XA5, 2018 WR1, 2018 WH2, 2018 VW6, 2018 TS, 2018 TP2, 2009 XV1, 2008 WX32, 2002 XQ90, 523610, 523604, 482054, 450238, 424482, 359592, 173664
K63Pascoli Obs. in Italy, 1 in MPEC 2018-Y02 -- 2002 XQ90
104San Marcello Pistoiese Obs. in Italy, 3 in MPECs 2018-Y02, 2018-Y06 & 2018-Y08 -- 2018 XZ4, 2018 XB5, 2002 XQ90
C95SATINO-1 in France, 3 in MPECs 2018-Y02, 2018-Y06 & 2018-Y08 -- 2018 XZ4, 2018 XB5, 2002 XQ90
204Schiaparelli Obs. in Italy, 4 in MPECs 2018-Y02, 2018-Y06, 2018-Y08 & 2018-Y10 -- 2018 XZ4, 2018 XD5, 2018 XB5, 2002 XQ90
G409B. Lutkenhoner in Germany via Slooh.com Canary Islands Obs. in the Canary Islands, 1 in MPEC 2018-Y02 -- 2002 XQ90
587Sormano Obs. in Italy, 3 in MPECs 2018-Y02, 2018-Y06 & 2018-Y08 -- 2018 XZ4, 2018 XB5, 2002 XQ90
291Spacewatch 1.8m telescope in Arizona, 1 in MPEC 2018-Y12 -- 2016 BT13
I52Steward Obs. Mt. Lemmon Station in Arizona, 5 in MPECs 2018-Y02, 2018-Y03, 2018-Y04, 2018-Y05 & 2018-Y06 -- 2018 XZ4, 2018 XY4, 2018 XX4, 2018 XW4, 2002 XQ90
L01Visnjan Obs., 9 in MPECs 2018-Y02, 2018-Y03, 2018-Y04, 2018-Y05, 2018-Y06, 2018-Y07, 2018-Y08, 2018-Y09 & 2018-Y10 -- 2018 XZ4, 2018 XY4, 2018 XX4, 2018 XW4, 2018 XD5, 2018 XC5, 2018 XB5, 2018 XA5, 2002 XQ90
718Wiggins Obs. in Utah, 1 in MPEC 2018-Y02 -- 2002 XQ90
J08Zonalunar Obs. in Spain, 1 in MPEC 2018-Y06 -- 2018 XZ4
For a list of all participating observatories that have Web addresses, see A/CC's Observatory Links page.

Impact Risk Monitoring  on 16 December '18

Summary Risk Table for Risk Assessments Updated Today   (last checks: NEODyS at 2358 UTC)
See the CRT page for a list of all objects rated recently as risks and our ephemerides page for a list of risk-listed objects under current observation.
The time horizon for JPL and NEODyS listings is 100 years, and both post impact solutions beyond that for some special objects.
For the latest official risk assessments, and for explanations of the terminology, see the NASA/JPL Sentry and NEODyS CLOMON2 risk pages.
0000NNN000

Object

Risk
Monitor
When
Noted
UTC
0000T0000
Year
Range

VI
#
000NN00
Prob
Cum
T0000
PS
Cum
T0000
PS
Max

T
S


Notes for Today's Latest Risk Assessments
2018 XR4NEODyS17402062-208852.52e-06-6.52-6.710NEODyS: "Based on 27 optical observations (of which 0 are rejected as outliers) from 2018-12-14.268 to 2018-12-15.258."
2005 TM173JPL Sentry19102018-21161519.432661e-07-5.41-6.270JPL: Computed at 08:06 April 8th of 2017 Pacific time based on 6 observations spanning 1.9467 days (2005-Oct-09.20072 to 2005-Oct-11.14743). Diameter approximately 0.051 km. from weighted mean H=24.12.

Legend: VI# = VI count, Prob Cum = cumulative probability, PS Cum/Max = cumulative/maximum Palermo Scale, TS = Torino Scale (next 100 years)

An impact solution, also known as a "virtual impactor" (VI), is not a prediction but rather a possibility derived from a variant orbit calculation that cannot be eliminated yet based on the existing data. Elimination can come quickly with just a little further observation or may take weeks or months, sometimes years. Once superceded or eliminated, a former impact solution has zero relevance to an object's risk. See Jon Giorgini's "Understanding Risk Pages" to learn more.

Chronology  on 16 December '18

Times are UTC for when items were noted or added by The Tracking News.

2000Noted Radar Astrometry database update - see above
1940Updated Traffic Report
1910Noted that JPL Sentry has updated its 2005 TM173 risk assessment - see above
1740Noted that NEODyS has posted 2018 XR4 as an impact risk - see above
Grabbed MPEC 2018-Y11 - 2018 DO4 - see above
Grabbed MPEC 2018-Y12 - Daily Orbit Update - see above
0518Grabbed MPEC 2018-Y02 - 2002 XQ90 - see above
Grabbed MPEC 2018-Y03 - 2018 XW4 - see above
Grabbed MPEC 2018-Y04 - 2018 XX4 - see above
Grabbed MPEC 2018-Y05 - 2018 XY4 - see above
Grabbed MPEC 2018-Y06 - 2018 XZ4 - see above
Grabbed MPEC 2018-Y07 - 2018 XA5 - see above
Grabbed MPEC 2018-Y08 - 2018 XB5 - see above
Grabbed MPEC 2018-Y09 - 2018 XC5 - see above
Grabbed MPEC 2018-Y10 - 2018 XD5 - see above
0316Grabbed MPEC 2018-Y01 - 2013 VX4 = 2018 XM4 - see above