Contents  on 15 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 15 December '18

Fourteen objects reported inside ten LD

Fourteen minor planets are reported within ten lunar distances (LD) of our home world today. Three of these are the nearest. Risk-listed 2018 VO9 comes its closest to Earth this time around, reaching 2.62 LD at 1136 UTC. New discovery 2018 XG4 also gets its closest -- 2.72 LD at 0126 UTC. And newly announced 2018 XS4 moves in from 3.74 to 2.83 LD. We note that 2013 VX4 is calculated to exit our ten-LD traffic reporting space today, but it has not yet been recovered and has an Earth passage uncertainty of plus-or-minus 7.06 days.

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  5.65 to 6.06 LD Nov. 8 - Dec. 25 intruder, NHATS target
0.97 LD Dec. 11 2018 XA4 5 m  9.61 to 12.46 LD Dec. 8 - 15 NEW, intruder, exits ten LD - MPEC
1.25 LD Dec. 10 2018 XX3 4 m  4.46 to 5.44 LD Nov. 30 - Dec. 20 NHATS target, risk
1.6   LD Dec. 21* 2018 XC4 19 m  9.9 from 11.6 LD today - Dec. 27 NEW, EPU +/- 38 mins.*, NHATS target, enters ten LD - MPEC
2.42 LD Dec. 12 2018 XL1 14 m  4.49 to 5.70 LD Dec. 5 - 19 NHATS target
2.62 LD today 2018 VO9 14 m  2.62 LD Nov. 29 - Dec. 31 NHATS target, Earth closest at 1136 UTC, risk
2.72 LD today 2018 XG4 11 m  2.72 LD Dec. 9 - 20 NEW, Earth closest at 0126 UTC - MPEC
2.76 LD tomorrow 2018 XS4 30 m  2.83 from 3.74 LD Dec. 11 - 21 NEW - MPEC
3.50 LD Dec. 11 2018 XM4 49 m  6.09 to 7.36 LD Dec. 5 - 17 NEW - MPEC
3.92 LD Dec. 2 2018 TG6 12 m  5.21 to 5.40 LD Oct. 30 - Jan. 5 NHATS target
4.1   LD Dec. 9* 2013 VX4 62 m  8.8 to 10.2 LD Dec. 3 - 15 EPU +/- 7.06 days*, exits ten LD
5.32 LD Dec. 17 2018 XR4 15 m  7.32 from 9.27 LD yesterday - Dec. 21 NEW, risk - MPEC
5.58 LD Dec. 13 2018 XJ1 18 m  6.11 to 6.81 LD Dec. 7 - 19
7.57 LD Dec. 13 2018 XF4 32 m  9.43 to 11.70 LD Dec. 11 - 15 NEW, exits ten LD - MPEC
* EPU = Earth passage uncertainty

This report was generated at 2020 UTC with nine discoveries, two of them in the approach table below and the others all active in the traffic table above (note the "NEW" notations). 2018 XA4 (MPEC) came the closest of these, intruding just inside the Earth-Moon system on December 11th, and one, 2018 XR4 (MPEC), has been risk listed.

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  11.19 from 12.26 LD Dec. 17 - 26 radar/NHATS target
5.3   LD Dec. 26* 2018 XE4 17 m  23.5 from 25.6 LD Dec. 22 - 30 NEW, EPU +/- 3.33 hours* - MPEC
7.8   LD Jan. 6* 2018 XO4 29 m  20.4 from 21.2 LD Dec. 30 - Jan. 13 NEW, EPU +/- 3.18 hours* - MPEC
7.3   LD Jan. 9* 2013 YM2 19 m  24.8 from 25.7 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. 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 15 December '18

The MPC's NEO Confirmation Page has 57 listings

When last checked at 2358 UTC today, the Minor Planet Center's Near Earth Object discovery Confirmation Page (NEOCP) had 57 objects listed. Of these, 23 were "one nighters." So far The Tracking News has counted a total of 80 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 15 December '18

Minor Planet Electronic Circulars

As of last check at 2358 UTC, there have been 21 MPECs posted today from the International Astronomical Union's Minor Planet Center in Cambridge, Massachusetts.


MPEC 2018-X136 - "20:27 UT" - Comet C/2018 W1 (Catalina)


MPEC 2018-X135 - "19:36 UT" - Comet C/2018 X2 (Fitzsimmons)


MPEC 2018-X134 - "18:18 UT" - 2018 XT4


MPEC 2018-X133 - "18:14 UT" - 2018 XS4


MPEC 2018-X132 - "18:09 UT" - 2018 XR4


MPEC 2018-X131 - "18:05 UT" - 2018 XQ4


MPEC 2018-X130 - "17:54 UT" - 2018 XP4


MPEC 2018-X129 - "17:38 UT" - 2018 XO4


MPEC 2018-X128 - "17:28 UT" - 2018 XN4


MPEC 2018-X127 - "17:13 UT" - 2014 NV65


<< DOU on 15 Dec. '18 >>  MPEC 2018-X126 - "13:05 UT" - Daily Orbit Update


MPEC 2018-X125 - "12:41 UT" - 2018 XM4


MPEC 2018-X124 - "04:17 UT" - 2018 XG4


MPEC 2018-X123 - "04:14 UT" - 2018 XF4


MPEC 2018-X122 - "04:11 UT" - 2018 XE4


MPEC 2018-X121 - "04:07 UT" - 2018 XD4


MPEC 2018-X120 - "04:04 UT" - 2018 XC4


MPEC 2018-X119 - "04:00 UT" - 2018 XB4


MPEC 2018-X118 - "03:57 UT" - 2018 XA4


MPEC 2018-X117 - "03:53 UT" - 2018 XZ3


MPEC 2018-X116 - "03:49 UT" - 2018 XY3

Observers  on 15 December '18

A total of 42 observers appear in today's MPECs.

CodeObserver / observatory
L2729PREMOTE Obs., 1 in MPEC 2018-X135 -- C/2018 X2
T05ATLAS Haleakala in Hawaii, 1 in MPEC 2018-X135 -- C/2018 X2
T08ATLAS Mauna Loa in Hawaii, 7 in MPECs 2018-X123, 2018-X126 & 2018-X133 -- 2018 XS4, 2018 XR, 2018 XG1, 2018 XF4, 2018 WA2, 2010 AK, 2009 SV17
C77Bernezzo Obs. in Italy, 2 in MPECs 2018-X123 & 2018-X135 -- 2018 XF4, C/2018 X2
160Castelmartini Obs. in Italy, 1 in MPEC 2018-X123 -- 2018 XF4
703Catalina Sky Survey (CSS) in Arizona, 2 in MPECs 2018-X125 & 2018-X136 -- 2018 XM4, C/2018 W1
K51Celado Obs. in Italy, 2 in MPECs 2018-X135 & 2018-X136 -- C/2018 X2, C/2018 W1
Z99Clixby Obs. in England, 1 in MPEC 2018-X135 -- C/2018 X2
850Cordell-Lorenz Obs. in Tennessee, 1 in MPEC 2018-X135 -- C/2018 X2
106Crni Vrh Obs. in Slovenia, 1 in MPEC 2018-X135 -- C/2018 X2
595Farra d'Isonzo Obs. in Italy, 1 in MPEC 2018-X123 -- 2018 XF4
157Frasso Sabino Obs. in Italy, 1 in MPEC 2018-X136 -- C/2018 W1
203GiaGa Obs. in Italy, 2 in MPECs 2018-X120 & 2018-X123 -- 2018 XF4, 2018 XC4
K88GINOP-KHK in Hungary, 1 in MPEC 2018-X135 -- C/2018 X2
J95Great Shefford Obs. in England, 4 in MPECs 2018-X120, 2018-X123, 2018-X124 & 2018-X133 -- 2018 XS4, 2018 XG4, 2018 XF4, 2018 XC4
H15ISON New Mexico Obs. in New Mexico, 3 in MPECs 2018-X123, 2018-X124 & 2018-X133 -- 2018 XS4, 2018 XG4, 2018 XF4
H06|Hidetaka Sato in Japan via iTelescope Obs. Mayhill in New Mexico, 1 in MPEC 2018-X135 -- C/2018 X2
P93JAXA Space Tracking & Communications Center (JAXA STCC) in Japan, 5 in MPECs 2018-X120, 2018-X123, 2018-X124, 2018-X126 & 2018-X133 -- 2018 XS4, 2018 XG4, 2018 XF4, 2018 XC4, 1998 YF10
K38M57 Obs. in Italy, 2 in MPECs 2018-X120 & 2018-X135 -- 2018 XC4, C/2018 X2
H01Magdalena Ridge Obs. (MRO) in New Mexico, 6 in MPECs 2018-X116, 2018-X117, 2018-X124, 2018-X128, 2018-X132 & 2018-X134 -- 2018 XZ3, 2018 XY3, 2018 XT4, 2018 XR4, 2018 XN4, 2018 XG4
568^R. Wainscoat on Mauna Kea in Hawaii, 7 in MPECs 2018-X116, 2018-X119, 2018-X121, 2018-X129, 2018-X130, 2018-X131 & 2018-X135 -- 2018 XY3, 2018 XQ4, 2018 XP4, 2018 XO4, 2018 XD4, 2018 XB4, C/2018 X2
568_Marco Micheli on Mauna Kea in Hawaii, 1 in MPEC 2018-X136 -- C/2018 W1
G96Mt. Lemmon Survey (MLS) in Arizona, 9 in MPECs 2018-X117, 2018-X118, 2018-X120, 2018-X123, 2018-X124, 2018-X125, 2018-X128, 2018-X132 & 2018-X134 -- 2018 XZ3, 2018 XT4, 2018 XR4, 2018 XN4, 2018 XM4, 2018 XG4, 2018 XF4, 2018 XC4, 2018 XA4
Z80Northolt Branch Obs. in England, 2 in MPECs 2018-X123 & 2018-X135 -- 2018 XF4, C/2018 X2
I41Palomar Transient Factory (PTF) in southern California, 9 in MPECs 2018-X123 & 2018-X126 -- 2018 XF4, 52387, 523587, 454177, 138859, 137805, 6178, 1864, 1862
F51Pan-STARRS 1 (PS1) in Hawaii, 17 in MPECs 2018-X119, 2018-X120, 2018-X121, 2018-X122, 2018-X126, 2018-X127, 2018-X129, 2018-X130 & 2018-X131 -- 2018 XQ4, 2018 XP4, 2018 XO4, 2018 XE4, 2018 XD4, 2018 XC4, 2018 XB4, 2016 OP5, 2014 NV65, 2009 SV17, 2006 UL217, 1992 BC, 65706, 476904, 171819, 141053, 140928
F52Pan-STARRS 2 (PS2) in Hawaii, 2 in MPECs 2018-X125 & 2018-X131 -- 2018 XQ4, 2018 XM4
K63Pascoli Obs. in Italy, 1 in MPEC 2018-X123 -- 2018 XF4
L04ROASTERR-1 in Romania, 1 in MPEC 2018-X135 -- C/2018 X2
104San Marcello Pistoiese Obs. in Italy, 2 in MPECs 2018-X123 & 2018-X133 -- 2018 XS4, 2018 XF4
H36Sandlot Obs. in Kansas, 1 in MPEC 2018-X116 -- 2018 XY3
C95SATINO-1 in France, 4 in MPECs 2018-X120, 2018-X123, 2018-X133 & 2018-X135 -- 2018 XS4, 2018 XF4, 2018 XC4, C/2018 X2
204Schiaparelli Obs. in Italy, 7 in MPECs 2018-X120, 2018-X123, 2018-X124, 2018-X132, 2018-X133, 2018-X134 & 2018-X135 -- 2018 XT4, 2018 XS4, 2018 XR4, 2018 XG4, 2018 XF4, 2018 XC4, C/2018 X2
033Schwarzschild Obs. in Germany, 1 in MPEC 2018-X135 -- C/2018 X2
Q11Shinshiro Obs., 1 in MPEC 2018-X135 -- C/2018 X2
G409B. Lutkenhoner in Germany via Slooh.com Canary Islands Obs. in the Canary Islands, 1 in MPEC 2018-X135 -- C/2018 X2
587Sormano Obs. in Italy, 1 in MPEC 2018-X133 -- 2018 XS4
691Spacewatch 0.9m telescope in Arizona, 4 in MPECs 2018-X116, 2018-X119, 2018-X122 & 2018-X131 -- 2018 XY3, 2018 XQ4, 2018 XE4, 2018 XB4
291Spacewatch 1.8m telescope in Arizona, 2 in MPECs 2018-X117 & 2018-X130 -- 2018 XZ3, 2018 XP4
I52Steward Obs. Mt. Lemmon Station in Arizona, 13 in MPECs 2018-X116, 2018-X117, 2018-X118, 2018-X119, 2018-X120, 2018-X123, 2018-X124, 2018-X126, 2018-X130, 2018-X131, 2018-X132, 2018-X134 & 2018-X135 -- 2018 XZ3, 2018 XY3, 2018 XT4, 2018 XR4, 2018 XQ4, 2018 XP4, 2018 XK2, 2018 XG4, 2018 XF4, 2018 XC4, 2018 XB4, 2018 XA4, C/2018 X2
461SZTE Asteroid Program in Hungary, 1 in MPEC 2018-X136 -- C/2018 W1
L01Visnjan Obs., 14 in MPECs 2018-X116, 2018-X117, 2018-X118, 2018-X119, 2018-X120, 2018-X121, 2018-X122, 2018-X123, 2018-X124, 2018-X125, 2018-X131, 2018-X132, 2018-X133 & 2018-X135 -- 2018 XZ3, 2018 XY3, 2018 XS4, 2018 XR4, 2018 XQ4, 2018 XM4, 2018 XG4, 2018 XF4, 2018 XE4, 2018 XD4, 2018 XC4, 2018 XB4, 2018 XA4, C/2018 X2
C51WISE in Earth polar orbit, 1 in MPEC 2018-X116 -- 2018 XY3
For a list of all participating observatories that have Web addresses, see A/CC's Observatory Links page.

Impact Risk Monitoring  on 15 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 XR4JPL Sentry20002062-211453.590074e-06-6.36-6.560JPL: Computed at 11:33 today Pacific time based on 27 observations spanning .98982 days (2018-Dec-14.26688 to 2018-Dec-15.2567). Diameter approximately 0.015 km. from weighted mean H=26.80.
2018 XB4NEODyS17302030-21182814.16e-05-3.91-4.55-NEODyS: "Based on 19 optical observations (of which 0 are rejected as outliers) from 2018-12-13.344 to 2018-12-14.824."
JPL Sentry06002030-21186114.42829738e-05-3.75-4.060JPL: Computed at 21:33 Dec. 14th Pacific time based on 19 observations spanning 1.4796 days (2018-Dec-13.34358 to 2018-Dec-14.823198). Diameter approximately 0.055 km. from weighted mean H=23.96.
2018 XY3NEODyS1730208611.34e-11-8.36-8.360NEODyS: "Based on 47 optical observations (of which 0 are rejected as outliers) from 2018-12-07.003 to 2018-12-14.546."
JPL Sentry05312034-211378.783e-09-5.30-5.670JPL: Computed at 21:07 Dec. 14th Pacific time based on 47 observations spanning 7.5431 days (2018-Dec-07.0021 to 2018-Dec-14.54519). Diameter approximately 0.340 km. from weighted mean H=20.00.
2014 JT79JPL Sentry05312018-211611331.8734236e-06-6.27-7.510JPL: 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.
2010 WW8JPL Sentry05312019-2112831.435612e-07-7.04-7.510JPL: Computed at 11:07 April 9th of 2017 Pacific time based on 12 observations spanning .06622 days (2010-Nov-30.37333 to 2010-Nov-30.43955). Diameter approximately 0.018 km. from weighted mean H=26.39.

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 15 December '18

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

2100Grabbed MPEC 2018-X136 - Comet C/2018 W1 (Catalina) - see above
2032Grabbed MPEC 2018-X135 - Comet C/2018 X2 (Fitzsimmons) - see above
2020Generated Traffic Report
2000Noted that JPL Sentry has posted 2018 XR4 as an impact risk - see above
1838Grabbed MPEC 2018-X131 - 2018 XQ4 - see above
Grabbed MPEC 2018-X132 - 2018 XR4 - see above
Grabbed MPEC 2018-X133 - 2018 XS4 - see above
Grabbed MPEC 2018-X134 - 2018 XT4 - see above
1802Grabbed MPEC 2018-X128 - 2018 XN4 - see above
Grabbed MPEC 2018-X129 - 2018 XO4 - see above
Grabbed MPEC 2018-X130 - 2018 XP4 - see above
1730Noted that NEODyS has posted 2018 XB4 as an impact risk - see above
Noted that NEODyS has posted 2018 XY3 as an impact risk - see above
Grabbed MPEC 2018-X125 - 2018 XM4 - see above
Grabbed MPEC 2018-X126 - Daily Orbit Update - see above
Grabbed MPEC 2018-X127 - 2014 NV65 - see above
0600Noted that JPL Sentry has posted 2018 XB4 as an impact risk - see above
0531Noted that JPL Sentry has updated its 2010 WW8 risk assessment - see above
Noted that JPL Sentry has updated its 2014 JT79 risk assessment - see above
Noted that JPL Sentry has posted 2018 XY3 as an impact risk - see above
0430Grabbed MPEC 2018-X116 - 2018 XY3 - see above
Grabbed MPEC 2018-X117 - 2018 XZ3 - see above
Grabbed MPEC 2018-X118 - 2018 XA4 - see above
Grabbed MPEC 2018-X119 - 2018 XB4 - see above
Grabbed MPEC 2018-X120 - 2018 XC4 - see above
Grabbed MPEC 2018-X121 - 2018 XD4 - see above
Grabbed MPEC 2018-X122 - 2018 XE4 - see above
Grabbed MPEC 2018-X123 - 2018 XF4 - see above
Grabbed MPEC 2018-X124 - 2018 XG4 - see above