Contents  on 23 December '18

Asteroid/Comet Connection (A/CC) Resources:

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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 23 December '18

Seven objects reported inside ten LD

There are seven asteroids reported within ten lunar distances (LD) of our planet today. Nearest of these are 2018 XC4, outbound from 2.84 to 4.38 LD, and risk-listed 2018 XN5, inbound from 3.88 to 3.15 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  8.93 to 9.35 LD Nov. 8 - Dec. 25 intruder, NHATS target
1.60 LD Dec. 21 2018 XC4 20 m  2.84 to 4.38 LD Dec. 15 - 27 NHATS target
2.62 LD Dec. 15 2018 VO9 14 m  5.41 to 5.96 LD Nov. 29 - Dec. 31 NHATS target, risk
2.96 LD tomorrow 2018 XN5 28 m  3.15 from 3.88 LD Dec. 18 - 31 NHATS target, risk - DOU
3.92 LD Dec. 2 2018 TG6 12 m  6.91 to 7.14 LD Oct. 30 - Jan. 5 NHATS target
5.3   LD Dec. 26* 2018 XE4 17 m  8.0 from 9.7 LD yesterday - Dec. 30 EPU +/- 3.33 hours*
7.36 LD yesterday 163899 2003 SD220 1.17 km  7.48 to 7.86 LD Dec. 17 - 26 radar/NHATS target
* EPU = Earth passage uncertainty

This report was generated at 2022 UTC with first follow-up in today's DOU MPEC for departed 2018 XF4, follow-up for inbound risk-listed 2018 XN5, and observation from earlier this month of departed objects 2018 XW, 2018 XE (1.30 days added to its previous 3.58-day observing arc), and risk-listed 2018 XA.

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 29 m  14.5 from 15.3 LD Dec. 30 - Jan. 13 EPU +/- 3.18 hours*, NHATS target
7.3   LD Jan. 9* 2013 YM2 19 m  17.6 from 18.5 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. 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.

NEOCP Activity  on 23 December '18

The MPC's NEO Confirmation Page has 36 listings

When last checked at 2358 UTC today, the Minor Planet Center's Near Earth Object discovery Confirmation Page (NEOCP) had 36 objects listed. Of these, nineteen were "one nighters."

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 23 December '18

Minor Planet Electronic Circulars

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


<< DOU on 23 Dec. '18 >>  MPEC 2018-Y62 - "13:06 UT" - Daily Orbit Update


MPEC 2018-Y61 - "12:18 UT" - 2016 SV1

Observers  on 23 December '18

Eight observers appear in today's MPECs.

CodeObserver / observatory
H21Astronomical Research Obs. Westfield in Illinois, 22 in MPEC 2018-Y62 -- 2018 XW5, 2018 XW, 2018 XS, 2018 XF4, 2018 XE, 2018 XB2, 2018 XA5, 2018 XA, 2018 WR1, 2018 WP2, 2018 WO2, 2018 WO, 2018 WN2, 2018 WB2, 2018 WA2, 2018 VL7, 2018 TK2, 2018 TC3, 2018 SA3, 2010 MF1, 53426, 310737
160Castelmartini Obs. in Italy, 3 in MPEC 2018-Y62 -- 2018 XA, 454100, 424482
695^Spacewatch via Kitt Peak Natl. Obs. (KPNO) in Arizona, 11 in MPEC 2018-Y62 -- 2018 YJ, 2018 YH, 2018 XV5, 2018 XG5, 2018 XE5, 2018 XB4, 2018 XB1, 2018 WP2, 2018 UY, 2018 UA1, 2018 TY2
F51Pan-STARRS 1 in Hawaii, 1 in MPEC 2018-Y62 -- 2016 EB85
C95SATINO-1 in France, 1 in MPEC 2018-Y62 -- 2010 GT7
T12UH/Tholen NEO Follow-Up 2.24m Telescope in Hawaii, 1 in MPEC 2018-Y61 -- 2016 SV1
718Wiggins Obs. in Utah, 1 in MPEC 2018-Y62 -- 2018 XN5
C51WISE in Earth polar orbit, 1 in MPEC 2018-Y62 -- 162741
For a list of all participating observatories that have Web addresses, see A/CC's Observatory Links page.

Impact Risk Monitoring  on 23 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 YJNEODyS22072031-2114141.6e-07-3.45-3.780NEODyS #2 for the day: "Based on 30 optical observations (of which 0 are rejected as outliers) from 2018-12-16.536 to 2018-12-22.539."
JPL Sentry18002031-2111101.354129e-07-3.56-3.970JPL: Computed at 07:55 today Pacific time based on 30 observations spanning 6.0035 days (2018-Dec-16.5351 to 2018-Dec-22.5386). Diameter approximately 0.681 km. from weighted mean H=18.48.
2018 XV5NEODyS2207R E M O V E D-
JPL Sentry1800R E M O V E DJPL: Risk listing removed at 1557 UTC today
2018 XN5NEODyS22072091-211422.33e-07-7.29-7.30NEODyS #2 for the day: "Based on 38 optical observations (of which 0 are rejected as outliers) from 2018-12-15.310 to 2018-12-23.096."
JPL Sentry18002089-208926.892e-07-6.67-6.900JPL: Computed at 08:01 today Pacific time based on 38 observations spanning 7.7861 days (2018-Dec-15.30928 to 2018-Dec-23.09542). Diameter approximately 0.028 km. from weighted mean H=25.39.
2018 XG5NEODyS22072069-208321.41e-07-4.62-4.710NEODyS: "Based on 26 optical observations (of which 0 are rejected as outliers) from 2018-12-13.395 to 2018-12-23.176."
JPL Sentry18002069-208322.1257e-07-4.47-4.770JPL: Computed at 07:53 today Pacific time based on 26 observations spanning 9.7811 days (2018-Dec-13.39431 to 2018-Dec-23.17539). Diameter approximately 0.280 km. from weighted mean H=20.40.
2018 XB4NEODyS22072051-21181293.12e-05-4.31-4.87-NEODyS #2 for the day: "Based on 26 optical observations (of which 0 are rejected as outliers) from 2018-12-13.344 to 2018-12-23.154."
JPL Sentry18002051-2118873.74699902e-05-4.22-4.670JPL: Computed at 08:07 today Pacific time based on 26 observations spanning 9.8096 days (2018-Dec-13.34358 to 2018-Dec-23.15322). Diameter approximately 0.055 km. from weighted mean H=23.95.
2018 XANEODyS2207209922.11e-08-7.18-7.360NEODyS #2 for the day: "Based on 141 optical observations (of which 3 are rejected as outliers) from 2018-12-01.348 to 2018-12-21.270."
JPL Sentry18002099-209923.306e-08-6.97-7.140JPL: Computed at 07:42 today Pacific time based on 139 observations spanning 19.922 days (2018-Dec-01.34686 to 2018-Dec-21.26929). Diameter approximately 0.063 km. from weighted mean H=23.64.
2018 WA3NEODyS05152055-206026.34e-06-6.32-6.330NEODyS: "Based on 31 optical observations (of which 0 are rejected as outliers) from 2018-11-29.262 to 2018-12-09.532."
2014 JT79JPL Sentry18002019-211611301.8524926e-06-6.32-7.750JPL: Computed at 19:19 April 6th of 2017 Pacific time based on 11 observations spanning 2.8075 days (2014-May-02.40649 to 2014-May-05.21401). Diameter approximately 0.013 km. from weighted mean H=27.12.

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 23 December '18

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

2207Noted that NEODyS has updated its 2018 XA risk assessment - see above
Noted that NEODyS has updated its 2018 XB4 risk assessment - see above
Noted that NEODyS has updated its 2018 XG5 risk assessment - see above
Noted that NEODyS has updated its 2018 XN5 risk assessment - see above
Noted that NEODyS has removed 2018 XV5 as an impact risk - see above
Noted that NEODyS has updated its 2018 YJ risk assessment - see above
2022Generated Traffic Report
1800Noted that JPL Sentry has updated its 2014 JT79 risk assessment - see above
Noted that JPL Sentry has updated its 2018 XA risk assessment - see above
Noted that JPL Sentry has updated its 2018 XB4 risk assessment - see above
Noted that JPL Sentry has updated its 2018 XG5 risk assessment - see above
Noted that JPL Sentry has updated its 2018 XN5 risk assessment - see above
Noted that JPL Sentry has removed 2018 XV5 as an impact risk - see above
Noted that JPL Sentry has updated its 2018 YJ risk assessment - see above
Grabbed MPEC 2018-Y61 - 2016 SV1 - see above
Grabbed MPEC 2018-Y62 - Daily Orbit Update - see above
0515Noted that NEODyS has updated its 2018 WA3 risk assessment - see above
Noted that NEODyS has updated its 2018 XA risk assessment - see above
Noted that NEODyS has updated its 2018 XB4 risk assessment - see above
Noted that NEODyS has updated its 2018 XN5 risk assessment - see above
Noted that NEODyS has updated its 2018 YJ risk assessment - see above