Contents  on 18 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 18 December '18

Twelve objects reported inside ten LD

There are twelve minor objects reported within ten lunar distances (LD) of Earth today. Nearest is risk-listed 2018 VO9, which heads away from 3.07 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  6.87 to 7.28 LD Nov. 8 - Dec. 25 intruder, NHATS target
1.25 LD Dec. 10 2018 XX3 4 m  7.44 to 8.45 LD Nov. 30 - Dec. 20 NHATS target, risk
1.6   LD Dec. 21* 2018 XC4 19 m  4.9 from 6.5 LD Dec. 15 - 27 EPU +/- 6 mins.*, NHATS target
2.42 LD Dec. 12 2018 XL1 14 m  8.27 to 9.58 LD Dec. 5 - 19 NHATS target
2.62 LD Dec. 15 2018 VO9 14 m  3.07 to 3.44 LD Nov. 29 - Dec. 31 NHATS target, risk
2.72 LD Dec. 15 2018 XG4 11 m  5.80 to 7.39 LD Dec. 9 - 20
2.76 LD Dec. 16 2018 XS4 30 m  4.25 to 5.85 LD Dec. 11 - 21
3.0   LD Dec. 24* 2018 XN5 25 m  8.7 from 10.1 LD today - Dec. 31 EPU +/- 52 mins.*, NHATS target, enters ten LD, risk
3.92 LD Dec. 2 2018 TG6 12 m  5.80 to 6.01 LD Oct. 30 - Jan. 5 NHATS target
5.32 LD yesterday 2018 XR4 15 m  5.32 to 5.96 LD Dec. 14 - 21 risk
5.58 LD Dec. 13 2018 XJ1 18 m  8.74 to 9.87 LD Dec. 7 - 19
7.36 LD Dec. 22 163899 2003 SD220 1.17 km  8.50 from 9.28 LD yesterday - Dec. 26 radar/NHATS target
* EPU = Earth passage uncertainty

This report was generated at 2042 UTC with follow-up in today's DOU MPEC for departed 2018 XB5.

Approaching - sorted by 10-LD bubble entry date
Earth passage I D ~Size Distance today  Inside ten LD Notes
5.3   LD Dec. 26* 2018 XE4 17 m  17.4 from 19.4 LD Dec. 22 - 30 EPU +/- 3.33 hours*
7.8   LD Jan. 6* 2018 XO4 29 m  18.2 from 18.9 LD Dec. 30 - Jan. 13 EPU +/- 3.18 hours*, NHATS target
7.3   LD Jan. 9* 2013 YM2 19 m  22.1 from 23.0 LD Jan. 2 - 16 EPU +/- 3.75 days*, NHATS target


<< Reading:  Carnegie Science has a news item about the discovery of 2018 VG18 (MPEC) as the furthest known planetary object in the Solar System. Bad Astronomy has a report.



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 18 December '18

The MPC's NEO Confirmation Page has 67 listings

When last checked at 2358 UTC today, the Minor Planet Center's Near Earth Object discovery Confirmation Page (NEOCP) had 67 objects listed. Of these, 27 were "one nighters." So far The Tracking News has counted a total of 76 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 18 December '18

Minor Planet Electronic Circulars

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


MPEC 2018-Y31 - "20:32 UT" - 2018 YB


MPEC 2018-Y30 - "20:28 UT" - 2018 YA


MPEC 2018-Y29 - "20:25 UT" - 2018 XY5


MPEC 2018-Y28 - "20:21 UT" - 2018 XX5


MPEC 2018-Y27 - "20:18 UT" - 2018 XW5


MPEC 2018-Y26 - "20:14 UT" - 2018 XV5


<< DOU on 18 Dec. '18 >>  MPEC 2018-Y25 - "13:04 UT" - Daily Orbit Update

Observers  on 18 December '18

Thirteen observers appear in today's MPECs.

CodeObserver / observatory
H21Astronomical Research Obs. Westfield in Illinois, 5 in MPECs 2018-Y26, 2018-Y27, 2018-Y28, 2018-Y29 & 2018-Y30 -- 2018 YA, 2018 XY5, 2018 XX5, 2018 XW5, 2018 XV5
T05ATLAS Haleakala in Hawaii, 3 in MPEC 2018-Y25 -- 2018 XK5, 2018 XB5, 2018 VB9
V06Catalina Sky Survey Kuiper Telescope in Arizona, 1 in MPEC 2018-Y27 -- 2018 XW5
734Farpoint Obs. in Kansas, 1 in MPEC 2018-Y26 -- 2018 XV5
H01Magdalena Ridge Obs. in New Mexico, 1 in MPEC 2018-Y26 -- 2018 XV5
568^R. Wainscoat on Mauna Kea in Hawaii, 4 in MPECs 2018-Y28, 2018-Y29, 2018-Y30 & 2018-Y31 -- 2018 YB, 2018 YA, 2018 XY5, 2018 XX5
G96Mt. Lemmon Survey in Arizona, 1 in MPEC 2018-Y26 -- 2018 XV5
F51Pan-STARRS 1 (PS1) in Hawaii, 10 in MPECs 2018-Y25, 2018-Y27, 2018-Y28, 2018-Y29, 2018-Y30 & 2018-Y31 -- 2018 YB, 2018 YA, 2018 XY5, 2018 XX5, 2018 XW5, 2018 XS3, 2018 WC1, 2018 KC3, 2010 FY80, 2005 UF1
H36Sandlot Obs. in Kansas, 1 in MPEC 2018-Y31 -- 2018 YB
I52Steward Obs. Mt. Lemmon Station in Arizona, 1 in MPEC 2018-Y26 -- 2018 XV5
T12UH/Tholen NEO Follow-Up 2.24m Telescope in Hawaii, 1 in MPEC 2018-Y25 -- 302169
L01Visnjan Obs., 5 in MPECs 2018-Y26, 2018-Y27, 2018-Y28, 2018-Y29 & 2018-Y31 -- 2018 YB, 2018 XY5, 2018 XX5, 2018 XW5, 2018 XV5
C51WISE in Earth polar orbit, 2 in MPEC 2018-Y25 -- 17274, 4596
For a list of all participating observatories that have Web addresses, see A/CC's Observatory Links page.

Impact Risk Monitoring  on 18 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 XW5JPL Sentry22042026-2116393.81105e-08-4.25-4.700JPL: Computed at 13:36 today Pacific time based on 12 observations spanning 2.7798 days (2018-Dec-14.56157 to 2018-Dec-17.341322). Diameter approximately 0.570 km. from weighted mean H=18.87.
2018 XV5JPL Sentry22042037-2110163.62339e-08-4.01-4.280JPL: Computed at 13:29 today Pacific time based on 23 observations spanning 3.5616 days (2018-Dec-14.32034 to 2018-Dec-17.881952). Diameter approximately 0.912 km. from weighted mean H=17.85.
2018 XN5NEODyS17202048-2115311.44e-05-5.53-6.090NEODyS: "Based on 12 optical observations (of which 0 are rejected as outliers) from 2018-12-15.310 to 2018-12-17.222."
2018 XG5NEODyS17202030-2118391.02e-06-3.60-3.83-NEODyS: "Based on 20 optical observations (of which 0 are rejected as outliers) from 2018-12-13.395 to 2018-12-16.309."

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 18 December '18

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

2204Noted that JPL Sentry has posted 2018 XV5 as an impact risk - see above
Noted that JPL Sentry has posted 2018 XW5 as an impact risk - see above
2042Generated Traffic Report
2038Grabbed MPEC 2018-Y26 - 2018 XV5 - see above
Grabbed MPEC 2018-Y27 - 2018 XW5 - see above
Grabbed MPEC 2018-Y28 - 2018 XX5 - see above
Grabbed MPEC 2018-Y29 - 2018 XY5 - see above
Grabbed MPEC 2018-Y30 - 2018 YA - see above
Grabbed MPEC 2018-Y31 - 2018 YB - see above
1720Noted that NEODyS has posted 2018 XG5 as an impact risk - see above
Noted that NEODyS has posted 2018 XN5 as an impact risk - see above
Grabbed MPEC 2018-Y25 - Daily Orbit Update - see above