Contents  on 29 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 29 December '18

Four objects reported inside ten LD

There are four Solar-System small bodies reported moving inside ten lunar distances (LD) of Earth today, all outbound and further away than five LD.

Neighborhood Traffic - sorted by Earth passage distance, grouped by 2.41, 5.0 & 10.0 LD boundaries
Earth passage I D ~Size Distance today  Inside ten LD Notes
2.62 LD Dec. 15 2018 VO9 14 m  8.81 to 9.39 LD Nov. 29 - Dec. 31 NHATS target, risk
2.96 LD Dec. 24 2018 XN5 28 m  6.71 to 8.01 LD Dec. 18 - 31 NHATS target, risk
3.92 LD Dec. 2 2018 TG6 12 m  8.33 to 8.57 LD Oct. 30 - Jan. 5 NHATS target
5.3   LD Dec. 26* 2018 XE4 17 m  7.0 to 8.5 LD Dec. 22 - 30 EPU +/- 3.33 hours*
* EPU = Earth passage uncertainty

This report was generated at 1840 UTC with the discovery at mid-month of now departed 2018 YG2 (DOU), which is calculated with some uncertainty to have passed our planet at about 2.7 LD on December 17th.

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  10.5 from 11.1 LD tomorrow - Jan. 13 EPU +/- 17 mins.*, NHATS target
7.3   LD Jan. 9* 2013 YM2 19 m  12.6 from 13.3 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. See also current sky chart and object details (alt-details), ephemerides, and today's timeline.

NEOCP Activity  on 29 December '18

The MPC's NEO Confirmation Page has 9 listings

When last checked at 2358 UTC today, the Minor Planet Center's Near Earth Object discovery Confirmation Page (NEOCP) had nine objects listed. Of these, five 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 29 December '18

Minor Planet Electronic Circulars

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

<< DOU on 29 Dec. '18 >>  MPEC 2018-Y92 - "13:05 UT" - Daily Orbit Update

Observers  on 29 December '18

Eleven observers appear in today's MPEC.

CodeObserver / observatory
H21Astronomical Research Obs. Westfield in Illinois, 8 in MPEC 2018-Y92 -- 2018 YJ, 2018 YH2, 2018 WV2, 2018 VZ9, 2018 TO6, 2018 LG1, 2018 LE4, 2005 YA37
160Castelmartini Obs. in Italy, 14 in MPEC 2018-Y92 -- 2018 XZ4, 2018 XB2, 2018 TS, 2010 AK, 2007 YQ56, 2003 NW1, 2002 XQ90, 523604, 457260, 412995, 242147, 141498, 2061, 1943
807|Robert Holmes in Illinois via Cerro Tololo Inter-American Obs. in Chile, 1 in MPEC 2018-Y92 -- 2018 XE20
K88GINOP-KHK in Hungary, 2 in MPEC 2018-Y92 -- 2018 XZ2, 2018 WR1
568^R. Wainscoat on Mauna Kea in Hawaii, 1 in MPEC 2018-Y92 -- 2018 XE20
I41Palomar Transient Factory in southern California, 1 in MPEC 2018-Y92 -- 2018 YG2
F51Pan-STARRS 1 (PS1) in Hawaii, 7 in MPEC 2018-Y92 -- 2018 YH2, 2018 XE20, 2018 XC20, 2016 PL66, 2015 LP46, 2013 LH25, 2013 DR9
C95SATINO-1 in France, 2 in MPEC 2018-Y92 -- 2002 XC91, 3288
G40!M. Kumrucu-Lohmiller in Massachusetts via Canary Islands Obs. in the Canary Islands, 1 in MPEC 2018-Y92 -- 2018 XT2
G403Tony Evans in Portugal via Canary Islands Obs. in the Canary Islands, 1 in MPEC 2018-Y92 -- 2018 XV
691Spacewatch 0.9m telescope in Arizona, 2 in MPEC 2018-Y92 -- 2018 XC20, 2017 TV4
T12UH/Tholen NEO Follow-Up 2.24m Telescope in Hawaii, 1 in MPEC 2018-Y92 -- 2018 VQ9
For a list of all participating observatories that have Web addresses, see A/CC's Observatory Links page.

Impact Risk Monitoring  on 29 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.





Notes for Today's Latest Risk Assessments
2018 YH2JPL Sentry17312024-2118873.037227e-07-5.30-5.950JPL: Computed at 07:56 today Pacific time based on 6 observations spanning .78326 days (2018-Dec-17.61903 to 2018-Dec-18.402294). Diameter approximately 0.082 km. from weighted mean H=23.08.
2018 YJJPL Sentry1731R E M O V E DJPL: Risk listing removed at 1537 UTC today
2018 XG5NEODyS1731208312.28e-07-4.45-4.450NEODyS: "Based on 32 optical observations (of which 0 are rejected as outliers) from 2018-12-13.395 to 2018-12-28.108."

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 29 December '18

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

1840Generated Traffic Report
1731Noted that NEODyS has updated its 2018 XG5 risk assessment - see above
Noted that JPL Sentry has posted 2018 YH2 as an impact risk - see above
Noted that JPL Sentry has removed 2018 YJ as an impact risk - see above
Grabbed MPEC 2018-Y92 - Daily Orbit Update - see above