Contents  on 25 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 25 December '18

Seven objects reported inside ten LD

Seven minor objects are reported to be less than ten lunar distances (LD) from Earth today. Nearest is risk-listed 2018 XN5, which moves out from 2.98 to 3.44 LD.

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  9.77 to 10.19 LD Nov. 8 - today intruder, NHATS target, exits ten LD
1.60 LD Dec. 21 2018 XC4 20 m  6.03 to 7.71 LD Dec. 15 - 27 NHATS target
2.62 LD Dec. 15 2018 VO9 14 m  6.52 to 7.09 LD Nov. 29 - Dec. 31 NHATS target, risk
2.96 LD yesterday 2018 XN5 28 m  2.98 to 3.44 LD Dec. 18 - 31 NHATS target, risk - DOU
3.92 LD Dec. 2 2018 TG6 12 m  7.38 to 7.61 LD Oct. 30 - Jan. 5 NHATS target
5.3   LD tomorrow* 2018 XE4 17 m  5.6 from 6.6 LD Dec. 22 - 30 EPU +/- 3.33 hours*
7.36 LD Dec. 22 163899 2003 SD220 1.17 km  8.46 to 9.25 LD Dec. 17 - 26 radar/NHATS target
* EPU = Earth passage uncertainty

This report was generated at 2216 UTC with follow-up in today's DOU MPEC for approaching 2018 XO4, outbound risk-listed 2018 XN5, departed objects 2018 YA1, risk-listed 2018 XX3, and 475534 2006 TS7, and distant objects 2013 UG1 and 68216 2001 CV26, plus astrometry from earlier this year for 2018 XW, 2018 WV, 2018 UK1, 2018 UF1, and 2017 VR12.

Approaching - sorted by 10-LD bubble entry date
Earth passage I D ~Size Distance today  Inside ten LD Notes
7.8   LD Jan. 6* 2018 XO4 30 m  13.1 from 13.8 LD Dec. 30 - Jan. 13 EPU +/- 17 mins.*, NHATS target - DOU
7.3   LD Jan. 9* 2013 YM2 19 m  15.8 from 16.7 LD Jan. 2 - 16 EPU +/- 3.75 days*, NHATS target



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. "Distant" is used here to describe objects that have approached Earth within ten LD since A/CC began these traffic reports eleven-plus years ago but are not presently coming so close. Object temporal distances are derived by A/CC from JPL Horizons data. See also current sky chart and object details (alt-details), ephemerides, and today's timeline.

NEOCP Activity  on 25 December '18

The MPC's NEO Confirmation Page has 12 listings

When last checked at 2358 UTC today, the Minor Planet Center's Near Earth Object discovery Confirmation Page (NEOCP) had twelve objects listed. Of these, four were "one nighters." So far The Tracking News has counted a total of 29 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 25 December '18

Minor Planet Electronic Circulars

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


MPEC 2018-Y68 - "23:37 UT" - 2017 OL68


MPEC 2018-Y67 - "16:33 UT" - 2018 YC2


<< DOU on 25 Dec. '18 >>  MPEC 2018-Y66 - "13:05 UT" - Daily Orbit Update

Observers  on 25 December '18

A total of 27 observers appear in today's MPECs.

CodeObserver / observatory
H21Astronomical Research Obs. Westfield in Illinois, 9 in MPEC 2018-Y66 -- 2018 XU6, 2018 WV, 2018 VG5, 2018 VA, 2018 UV1, 2018 UR1, 2018 UK1, 2018 UF1, 2018 DF2
T05ATLAS Haleakala in Hawaii, 1 in MPEC 2018-Y66 -- 2018 NB
T08ATLAS Mauna Loa in Hawaii, 1 in MPEC 2018-Y66 -- 418849
Q68Blue Mountains Obs. in New South Wales, 1 in MPEC 2018-Y66 -- 455550
160Castelmartini Obs. in Italy, 30 in MPEC 2018-Y66 -- 2018 XW, 2018 XR, 2018 XB1, 2018 TS, 2018 QN1, 2010 GT7, 2005 YY36, 2003 NW1, 96315, 90403, 523824, 523631, 523619, 523604, 518735, 457260, 443923, 438429, 414960, 412995, 18736, 18109, 17274, 162004, 141498, 137084, 6456, 6178, 2061, 1943
703Catalina Sky Survey (CSS) in Arizona, 31 in MPEC 2018-Y66 -- 2018 UM1, 2018 UJ1, 2018 PE22, 2013 UG1, 2010 AK, 65733, 54401, 523621, 523604, 523603, 523596, 523595, 481542, 468481, 446924, 443923, 422787, 397847, 381564, 349507, 20790, 17274, 170891, 16834, 155340, 155334, 152931, 141498, 137805, 9058, 5143
V06Catalina Sky Survey Kuiper Telescope (CSS-Kuiper) in Arizona, 3 in MPEC 2018-Y66 -- 2018 TW5, 2018 TN5, 2018 PQ23
822Cordoba Obs. in Argentina, 2 in MPEC 2018-Y66 -- 2018 KV, 2013 AV60
595Farra d'Isonzo Obs. in Italy, 1 in MPEC 2018-Y66 -- 418849
J95Great Shefford Obs. in England, 1 in MPEC 2018-Y66 -- 475534
P93JAXA Space Tracking & Communications Center (JAXA STCC) in Japan, 2 in MPEC 2018-Y66 -- 2018 VY8, 2018 VT8
695^Spacewatch via Kitt Peak Natl. Obs. (KPNO) in Arizona, 8 in MPECs 2018-Y66 & 2018-Y67 -- 2018 YZ1, 2018 YC2, 2018 XX3, 2018 XG5, 2018 VT8, 2018 VK10, 2018 VG3, 2011 XA3
246KLENOT in the Czech Republic, 1 in MPEC 2018-Y66 -- 2002 VE68
G96Mt. Lemmon Survey (MLS) in Arizona, 15 in MPECs 2018-Y66 & 2018-Y67 -- 2018 YC2, 2018 TV4, 2018 TQ1, 2018 TE3, 2018 SR2, 2015 NU2, 2011 UX192, 2004 PX27, 85804, 52762, 523631, 523603, 382459, 285638, 1863
C53NEOSSat in Earth orbit, 1 in MPEC 2018-Y66 -- 2017 VR12
Z80Northolt Branch Obs. in England, 5 in MPEC 2018-Y66 -- 2018 XZ2, 2018 XN5, 2018 WR1, 2007 YQ56, 2004 XP14
F51Pan-STARRS 1 (PS1) in Hawaii, 3 in MPEC 2018-Y66 -- 2018 YS, 2018 WR1, 459462
F52Pan-STARRS 2 (PS2) in Hawaii, 2 in MPEC 2018-Y66 -- 518463, 4953
D29Purple Mtn. Obs. Xuyi Station in China, 14 in MPEC 2018-Y66 -- 96590, 523788, 418929, 253106, 21277, 21088, 162168, 13553, 115052, 9856, 7358, 5751, 4401, 719
C95SATINO-1 in France, 1 in MPEC 2018-Y66 -- 2018 XZ1
Q21Southern Utsunomiya in Japan, 1 in MPEC 2018-Y66 -- 3200
691Spacewatch 0.9m telescope in Arizona, 13 in MPEC 2018-Y66 -- 2018 YA1, 2018 XZ1, 2018 XK5, 2018 VB9, 2018 UZ, 2018 UN1, 2018 UJ1, 2018 UJ, 2018 RL, 2018 MW6, 2018 GX4, 2009 WM1, 2007 VD12
291Spacewatch 1.8m telescope in Arizona, 7 in MPEC 2018-Y66 -- 2018 XO4, 2018 XB4, 2018 UY, 2012 FN62, 2007 WF55, 2007 VD12, 2004 XL14
W34Squirrel Valley Obs. in North Carolina, 2 in MPEC 2018-Y66 -- 68216, 345722
I52Steward Obs. Mt. Lemmon Station in Arizona, 7 in MPECs 2018-Y66 & 2018-Y67 -- 2018 YH, 2018 YC2, 2018 WV2, 2018 VG8, 2018 RJ7, 2018 PU10, 2008 UC95
T12UH/Tholen NEO Follow-Up 2.24m Telescope in Hawaii, 3 in MPECs 2018-Y66 & 2018-Y68 -- 2017 OL68, 2014 XU6, 2002 VE68
L01Visnjan Obs., 1 in MPEC 2018-Y67 -- 2018 YC2
For a list of all participating observatories that have Web addresses, see A/CC's Observatory Links page.

Impact Risk Monitoring  on 25 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 YZ1JPL Sentry17302064-211881.18792e-08-4.80-5.320JPL: Computed at 08:12 today Pacific time based on 16 observations spanning 4.7749 days (2018-Dec-20.63258 to 2018-Dec-25.40753). Diameter approximately 0.687 km. from weighted mean H=18.46.
NEODyS17302064-2118111.44e-08-4.63-5.17-NEODyS: "Based on 16 optical observations (of which 0 are rejected as outliers) from 2018-12-20.633 to 2018-12-25.408."
2018 XN5JPL Sentry17302089-208916.053e-08-7.72-7.720JPL: Computed at 08:22 today Pacific time based on 44 observations spanning 9.5804 days (2018-Dec-15.30928 to 2018-Dec-24.889641). Diameter approximately 0.028 km. from weighted mean H=25.38.
NEODyS1730211417.06e-08-7.81-7.810NEODyS: "Based on 44 optical observations (of which 0 are rejected as outliers) from 2018-12-15.310 to 2018-12-24.890."
2018 XG5JPL Sentry17302069-208321.786413e-07-4.59-4.590JPL: Computed at 08:18 today Pacific time based on 29 observations spanning 11.984 days (2018-Dec-13.39431 to 2018-Dec-25.37851). Diameter approximately 0.290 km. from weighted mean H=20.36.
NEODyS17302069-208331.22e-07-4.76-4.880NEODyS: "Based on 29 optical observations (of which 0 are rejected as outliers) from 2018-12-13.395 to 2018-12-25.379."
2018 XB4JPL Sentry17302052-2118595.14674638e-05-4.07-4.490JPL: Computed at 08:14 today Pacific time based on 29 observations spanning 11.816 days (2018-Dec-13.34358 to 2018-Dec-25.15929). Diameter approximately 0.055 km. from weighted mean H=23.94.
NEODyS17302051-21181034.13e-05-4.18-4.67-NEODyS: "Based on 29 optical observations (of which 0 are rejected as outliers) from 2018-12-13.344 to 2018-12-25.160."
2018 XX3JPL Sentry17302088-211241.202727e-06-8.56-8.660JPL: Computed at 08:25 today Pacific time based on 24 observations spanning 11.822 days (2018-Dec-13.30812 to 2018-Dec-25.13006). Diameter approximately 0.004 km. from weighted mean H=29.68.
NEODyS17302086-211668.73e-07-8.69-8.730NEODyS: "Based on 25 optical observations (of which 1 are rejected as outliers) from 2018-12-13.309 to 2018-12-25.131."

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 25 December '18

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

2358Grabbed MPEC 2018-Y68 - 2017 OL68 - see above
2216Generated Traffic Report
1730Noted that JPL Sentry has updated its 2018 XB4 risk assessment - see above
Noted that NEODyS has updated its 2018 XB4 risk assessment - see above
Noted that JPL Sentry has updated its 2018 XG5 risk assessment - see above
Noted that NEODyS has updated its 2018 XG5 risk assessment - see above
Noted that JPL Sentry has updated its 2018 XN5 risk assessment - see above
Noted that NEODyS has updated its 2018 XN5 risk assessment - see above
Noted that JPL Sentry has updated its 2018 XX3 risk assessment - see above
Noted that NEODyS has updated its 2018 XX3 risk assessment - see above
Noted that JPL Sentry has updated its 2018 YZ1 risk assessment - see above
Noted that NEODyS has posted 2018 YZ1 as an impact risk - see above
Grabbed MPEC 2018-Y66 - Daily Orbit Update - see above
Grabbed MPEC 2018-Y67 - 2018 YC2 - see above