Contents  on 24 December '17

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 24 December '17

Seven objects reported inside ten LD

There are seven visitors reported within ten lunar distances (LD) of our home world today. Nearest is newly announced 2017 YS1, which comes its closest to Earth on this passage, reaching 1.93 LD at 1644 UTC.

Earth passage I D ~Size Distance today  Inside ten LD Notes
1.77 LD Dec. 15 2017 YD1 3 m  5.52 to 6.14 LD Nov. 30 - Dec. 31 NEW, NHATS target, risk - MPEC
1.93 LD today 2017 YS1 6 m  1.93 LD Dec. 11 - Jan. 7 NEW, NHATS target, Earth closest at 1644 UTC - MPEC
2.24 LD Dec. 27 2017 YD2 6 m  4.53 from 6.23 LD Dec. 21 - Jan. 1 NEW, risk - MPEC
2.88 LD Dec. 22 2017 YE 7 m  3.36 to 4.00 LD Dec. 13 - 31 NHATS target
5.13 LD Dec. 26 2017 YQ1 42 m  9.00 from 13.19 LD today - Dec. 28 NEW, enters ten LD - MPEC
7.62 LD today 2017 WZ14 32 m  7.62 LD Dec. 18 - 30 radar/NHATS target, Earth closest at 2117 UTC
7.90 LD Dec. 22 2017 YW 15 m  8.22 to 8.91 LD Dec. 19 - 26 NEW - MPEC
Approaching (sorted by 10-LD bubble entry date)
7.74 LD Dec. 30 2017 YU1 19 m  11.93 from 13.28 LD Dec. 26 - Jan. 3 NEW, NHATS target - MPEC
3.7   LD Feb. 24* 2017 DR109 10 m  133.4 from 136.4 LD Feb. 18 - March 1 EPU +/- 30 mins.*, NHATS target
3.8   LD March 7* 2017 VR12 268 m  101.3 from 99.7 LD Feb. 28 - March 13 EPU +/- 7 mins.*, radar/NHATS target - DOU
* EPU = Earth passage uncertainty

This report was generated at 2056 UTC with ten discoveries that were announced late yesterday and four more that have been posted today. Six of these are in the active traffic table above, and eight more have already left our ten-LD traffic reporting "bubble." Basic facts about these last have been assembled in the "Newly Departed" table below. Today's DOU MPEC has first follow-up for 2017 YH1 and additional observation of 2017 YT1 -- both newly announced objects, as well as continuing follow-up for approaching 2017 VR12 and departed 2017 XS.

Newly Departed - Just discovered, already gone (sorted by closest approach)
Earth passage I D ~Size Inside ten LD Notes
1.04 LD Dec. 18 2017 YJ1 10 m  Dec. 13 - 22 Moon closest 0.55 LD Dec. 17, NHATS target - MPEC
1.52 LD Dec. 15* 2017 YM1 28 m  Dec. 11 - 19 EPU +/- 10 mins.*, Moon closest 1.33 LD Dec. 15, risk - MPEC
2.38 LD Dec. 18 2017 YH1 207 m  Dec. 15 - 20 MPEC, DOU
5.65 LD Dec. 20 2017 YP1 25 m  Dec. 17 - 23 MPEC
7.66 LD Dec. 18 2017 YL1 37 m  Dec. 16 - 20 MPEC
8.01 LD Dec. 20 2017 YT1 36 m  Dec. 18 - 21 MPEC, DOU
8.37 LD Dec. 20 2017 YN1 20 m  Dec. 17 - 23 NHATS target - MPEC
9.31 LD Dec. 11 2017 YB1 15 m  Dec. 9 - 13 NHATS target - MPEC



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 24 December '17

The MPC's NEO Confirmation Page has 98 listings

When last checked at 2358 UTC today, the Minor Planet Center's Near Earth Object discovery Confirmation Page (NEOCP) had 98 objects listed. Of these, 64 were "one nighters." So far The Tracking News has counted a total of 115 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 24 December '17

Minor Planet Electronic Circulars

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


MPEC 2017-Y83 - "16:54 UT" - 2017 YD2


MPEC 2017-Y82 - "16:50 UT" - 2017 YC2


MPEC 2017-Y81 - "16:46 UT" - 2017 YB2


MPEC 2017-Y80 - "16:42 UT" - 2017 YA2


MPEC 2017-Y79 - "16:38 UT" - 2017 YZ1


<< DOU on 24 Dec. '17 >>  MPEC 2017-Y78 - "13:04 UT" - Daily Orbit Update


MPEC 2017-Y77 - "04:15 UT" - 2017 YS1


MPEC 2017-Y76 - "04:11 UT" - 2017 YU1


MPEC 2017-Y75 - "04:07 UT" - 2017 YT1


MPEC 2017-Y74 - "04:03 UT" - 2017 YR1

Observers  on 24 December '17

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

CodeObserver / observatory
E23Arcadia Obs. in New South Wales, 1 in MPEC 2017-Y78 -- 2017 YE1
H21Astronomical Research Obs. Westfield in Illinois, 13 in MPEC 2017-Y78 -- 2017 WO28, 2017 SV20, 2017 SU20, 2017 ST20, 2017 SR12, 2017 SK21, 2017 SB14, 2017 QW17, 2017 EQ13, 2015 VR1, 96536, 501647, 475967
T05ATLAS Haleakala in Hawaii, 8 in MPEC 2017-Y78 -- 53110, 504928, 162998, 154589, 142040, 9950, 8567, 2202
T08ATLAS Mauna Loa in Hawaii, 2 in MPEC 2017-Y78 -- 2016 AU8, 1999 AF4
I47Auger Obs. in Argentina, 2 in MPEC 2017-Y78 -- 2017 XQ2, 2017 XD
073Bucharest Obs. in Romania, 1 in MPEC 2017-Y78 -- 418849
Z84Calar Alto Schmidt in Spain, 2 in MPECs 2017-Y74 & 2017-Y76 -- 2017 YU1, 2017 YR1
160Castelmartini Obs. in Italy, 15 in MPEC 2017-Y78 -- 2017 WX12, 88188, 504887, 438430, 333888, 21374, 189173, 154988, 154589, 140158, 136849, 8567, 8037, 3200, 2368
703Catalina Sky Survey (CSS) in Arizona, 36 in MPECs 2017-Y74 & 2017-Y78 -- 2017 YR1, 2017 YH1, 2017 YF1, 2017 XS, 2017 SS19, 2015 XK351, 2015 FO124, 1997 GC32, 96189, 87024, 53319, 53110, 505178, 496818, 495848, 422699, 411201, 351331, 333888, 285567, 253841, 243566, 15817, 142040, 141670, 140158, 138013, 137199, 137084, 11405, 100926, 7977, 4947, 2329, 2202, 1865
V06Catalina Sky Survey Kuiper Telescope (CSS-Kuiper) in Arizona, 14 in MPECs 2017-Y74, 2017-Y75, 2017-Y77, 2017-Y78, 2017-Y79, 2017-Y80, 2017-Y81, 2017-Y82 & 2017-Y83 -- 2017 YZ1, 2017 YT1, 2017 YS1, 2017 YR1, 2017 YD2, 2017 YC2, 2017 YB2, 2017 YA2, 2017 XP60, 2017 XN2, 2017 XH62, 2017 XG62, 2017 XF62, 2017 WO28
K51Celado Obs. in Italy, 1 in MPEC 2017-Y82 -- 2017 YC2
807|Robert Holmes in Illinois via Cerro Tololo Inter-American Obs. (CTIO) in Chile, 5 in MPECs 2017-Y78, 2017-Y79 & 2017-Y82 -- 2017 YZ1, 2017 YC2, 2017 XT2, 2017 XS2, 2017 XO2
H15ISON New Mexico Obs. in New Mexico, 1 in MPEC 2017-Y78 -- 11405
Z22MASTER IAC Obs. in the Canary Islands, 1 in MPEC 2017-Y78 -- 496861
568_Marco Micheli on Mauna Kea in Hawaii, 1 in MPEC 2017-Y76 -- 2017 YU1
711McDonald Obs. in Texas, 1 in MPEC 2017-Y74 -- 2017 YR1
B67Mirasteilas Obs. in Switzerland, 4 in MPEC 2017-Y78 -- 2017 VR12, 2017 SO17, 2014 VU1, 1999 AF4
G96Mt. Lemmon Survey (MLS) in Arizona, 38 in MPECs 2017-Y74, 2017-Y75, 2017-Y77, 2017-Y78, 2017-Y79, 2017-Y80, 2017-Y81, 2017-Y82 & 2017-Y83 -- 2017 YZ1, 2017 YT1, 2017 YS1, 2017 YR1, 2017 YD2, 2017 YC2, 2017 YB2, 2017 YA2, 2017 XP60, 2017 XF62, 2017 WW12, 2017 UW4, 2017 NU6, 2014 YD42, 2013 MZ5, 2010 SA12, 2008 CC175, 89355, 53319, 506779, 495960, 495848, 490581, 439898, 411201, 386720, 348595, 333908, 172034, 16834, 159399, 152931, 143651, 141874, 141670, 13651, 1866, 1865
F51Pan-STARRS 1 (PS1) in Hawaii, 35 in MPECs 2017-Y75, 2017-Y76 & 2017-Y78 -- 2017 YU1, 2017 YT1, 2017 XJ2, 2017 XA2, 2017 WL13, 2017 UC5, 2017 SM16, 2017 QO17, 2017 QL33, 2017 KT4, 2015 BR514, 2013 XS3, 2012 LE11, 2005 CV38, 88264, 86819, 85818, 65690, 495891, 490354, 415029, 361123, 351331, 350536, 331999, 317685, 265661, 243147, 232368, 228587, 216985, 20236, 189700, 154300, 2329
K63Pascoli Obs. in Italy, 1 in MPEC 2017-Y78 -- 2017 YH1
H36Sandlot Obs. in Kansas, 1 in MPEC 2017-Y82 -- 2017 YC2
204Schiaparelli Obs. in Italy, 4 in MPECs 2017-Y75, 2017-Y76, 2017-Y77 & 2017-Y83 -- 2017 YU1, 2017 YT1, 2017 YS1, 2017 YD2
W881Tony Evans in Portugal via Slooh.com Chile Obs. in Chile, 1 in MPEC 2017-Y78 -- 2017 VU14
W885M. Kumrucu-Lohmiller in Massachusetts via Slooh.com Chile Obs. in Chile, 1 in MPEC 2017-Y78 -- 2017 YH
691Spacewatch 0.9m telescope in Arizona, 3 in MPEC 2017-Y78 -- 2017 XH62, 2017 XA2, 85628
291Spacewatch 1.8m telescope in Arizona, 1 in MPEC 2017-Y78 -- 2009 SK2
I52Steward Obs. Mt. Lemmon Station in Arizona, 7 in MPECs 2017-Y75, 2017-Y77, 2017-Y79, 2017-Y80, 2017-Y81, 2017-Y82 & 2017-Y83 -- 2017 YZ1, 2017 YT1, 2017 YS1, 2017 YD2, 2017 YC2, 2017 YB2, 2017 YA2
926Tenagra II Obs. in Arizona, 7 in MPECs 2017-Y74, 2017-Y75, 2017-Y76, 2017-Y77, 2017-Y80, 2017-Y81 & 2017-Y83 -- 2017 YU1, 2017 YT1, 2017 YS1, 2017 YR1, 2017 YD2, 2017 YB2, 2017 YA2
For a list of all participating observatories that have Web addresses, see A/CC's Observatory Links page.

Impact Risk Monitoring  on 24 December '17

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 is 100 years from today and for NEODyS is usually the year 2090. Both also post impact solutions beyond 100 years for a few 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
2017 YD2JPL Sentry20502055-206545.86907e-07-8.06-8.110JPL: Computed at 11:11 today Pacific time based on 26 observations spanning 1.1541 days (2017-Dec-23.35847 to 2017-Dec-24.51253). Diameter approximately 0.006 km. from weighted mean H=28.70.
2017 YZ1NEODyS23022024-2117622.67e-06-2.84-2.890NEODyS: "Based on 24 optical observations (of which 3 are rejected as outliers) from 2017-12-20.426 to 2017-12-24.544."
JPL Sentry20502024-21171562.6280542e-06-3.01-3.310JPL: Computed at 11:10 today Pacific time based on 24 observations spanning 4.1180 days (2017-Dec-20.42481 to 2017-Dec-24.54286). Diameter approximately 0.220 km. from weighted mean H=20.90.
2017 YM1NEODyS23022048-2103401.24e-04-4.29-4.470NEODyS: "Based on 18 optical observations (of which 2 are rejected as outliers) from 2017-12-20.410 to 2017-12-22.129."
2017 YD1NEODyS2302210217.42e-06-8.00-8.00NEODyS: "Based on 26 optical observations (of which 2 are rejected as outliers) from 2017-12-20.247 to 2017-12-23.248."
2017 XS2NEODyS2237R E M O V E D-
JPL Sentry16302104-210421.4101e-08-8.77-8.930JPL: Computed at 08:04 today Pacific time based on 30 observations spanning 11.981 days (2017-Dec-11.35957 to 2017-Dec-23.340932). Diameter approximately 0.021 km. from weighted mean H=26.00.
2017 XO2NEODyS23022028-2115174.08e-06-4.00-4.00NEODyS: "Based on 31 optical observations (of which 1 are rejected as outliers) from 2017-12-10.337 to 2017-12-23.078."
JPL Sentry16302035-2111762.0217348e-05-3.40-3.710JPL: Computed at 08:15 today Pacific time based on 31 observations spanning 12.741 days (2017-Dec-10.33601 to 2017-Dec-23.07718). Diameter approximately 0.110 km. from weighted mean H=22.44.
2013 YBJPL Sentry16302018-2063277.46688874e-05-6.59-7.020JPL: Computed at 08:53 April 8th Pacific time based on 11 observations spanning .16022 days (2013-Dec-23.21048 to 2013-Dec-23.3707). Diameter approximately 0.002 km. from weighted mean H=31.45.

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 24 December '17

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

2302Noted that NEODyS has updated its 2017 XO2 risk assessment - see above
Noted that NEODyS has posted 2017 YD1 as an impact risk - see above
Noted that NEODyS has posted 2017 YM1 as an impact risk - see above
Noted that NEODyS has posted 2017 YZ1 as an impact risk - see above
2237Noted that NEODyS has removed 2017 XS2 as an impact risk - see above
2056Generated Traffic Report
2050Noted that JPL Sentry has posted 2017 YD2 as an impact risk - see above
Noted that JPL Sentry has posted 2017 YZ1 as an impact risk - see above
1746Grabbed MPEC 2017-Y79 - 2017 YZ1 - see above
Grabbed MPEC 2017-Y80 - 2017 YA2 - see above
Grabbed MPEC 2017-Y81 - 2017 YB2 - see above
Grabbed MPEC 2017-Y82 - 2017 YC2 - see above
Grabbed MPEC 2017-Y83 - 2017 YD2 - see above
1630Noted that JPL Sentry has updated its 2013 YB risk assessment - see above
Noted that JPL Sentry has updated its 2017 XO2 risk assessment - see above
Noted that JPL Sentry has updated its 2017 XS2 risk assessment - see above
Grabbed MPEC 2017-Y78 - Daily Orbit Update - see above
0432Grabbed MPEC 2017-Y74 - 2017 YR1 - see above
Grabbed MPEC 2017-Y75 - 2017 YT1 - see above
Grabbed MPEC 2017-Y76 - 2017 YU1 - see above
Grabbed MPEC 2017-Y77 - 2017 YS1 - see above