Contents  on 22 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 22 December '17

Five objects reported inside ten LD

Today there are five asteroids reported within ten lunar distances (LD) of Earth. Nearest is 2017 YE, which comes its closest to our planet this time around, reaching 2.88 LD at 0836 UTC.

Earth passage I D ~Size Distance today  Inside ten LD Notes
2.51 LD Dec. 19 2017 XY61 19 m  8.46 to 11.48 LD Dec. 16 - 22 exits ten LD
2.88 LD today 2017 YE 7 m  2.88 LD Dec. 13 - 31 NHATS target, Earth closest at 0836 UTC
3.35 LD Dec. 14 2006 XY 54 m  8.78 to 9.79 LD Dec. 5 - 23 NHATS target
5.16 LD Dec. 18 2017 XW60 9 m  9.40 to 11.08 LD Dec. 13 - 22 exits ten LD
7.62 LD Dec. 24 2017 WZ14 33 m  7.89 from 8.24 LD Dec. 18 - 30 radar/NHATS target
Approaching (sorted by 10-LD bubble entry date)
3.7   LD Feb. 24* 2017 DR109 10 m  139.4 from 142.5 LD Feb. 18 - March 1 EPU +/- 30 mins.*, NHATS target
3.8   LD March 7* 2017 VR12 267 m  103.0 from 104.7 LD Feb. 28 - March 13 EPU +/- 9 mins.*, radar/NHATS target
* EPU = Earth passage uncertainty

This report was generated at 1854 UTC with follow-up in today's DOU MPEC for three of this year's many departed radar targets: 2017 VT14, 171576 1999 VP11, and 496817 1989 VB.

Reading:  There is a joint news release from Arecibo and NASA/JPL about the return to operation of the Arecibo Observatory and "providing the best images to date of near-Earth asteroid [3200 Phaethon (1983 TB)]."
        Spain's science news agency SINC has an item about anticipating the not-so-close return of 2015 TB145 next October-November, allowing a team of observers to continue their study of this object in multiple light bands.



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 22 December '17

The MPC's NEO Confirmation Page has 59 listings

When last checked at 1922 UTC today, the Minor Planet Center's Near Earth Object discovery Confirmation Page (NEOCP) had 59 objects listed. Of these, nineteen were "one nighters." So far The Tracking News has counted a total of 61 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 22 December '17

Minor Planet Electronic Circulars

As of last check at 1922 UTC, there has been one MPEC posted today from the International Astronomical Union's Minor Planet Center in Cambridge, Massachusetts.


<< DOU on 22 Dec. '17 >>  MPEC 2017-Y51 - "13:05 UT" - Daily Orbit Update

Observers  on 22 December '17

Eleven observers appear in today's MPEC.

CodeObserver / observatory
H21Astronomical Research Obs. Westfield in Illinois, 19 in MPEC 2017-Y51 -- 2017 XM60, 2017 XD1, 2017 WG16, 2017 VU14, 2017 VM13, 2017 SL2, 2017 RT1, 2017 OD1, 2015 EZ, 2015 CZ, 2014 BY32, 2011 AW55, 2010 MQ1, 475967, 331999, 154988, 145656, 7977, 3360
703Catalina Sky Survey (CSS) in Arizona, 35 in MPEC 2017-Y51 -- 2017 XO60, 2017 WA15, 2014 YC15, 2014 QW296, 2013 TH5, 2008 WL, 2008 AX28, 2000 KN44, 85818, 85628, 68278, 53430, 507366, 506859, 496861, 496817, 457768, 439908, 438430, 349928, 322763, 307493, 265187, 262623, 228587, 21374, 190208, 185853, 177255, 16657, 153349, 152931, 143992, 136839, 1866
807|Robert Holmes in Illinois via Cerro Tololo Inter-American Obs. (CTIO) in Chile, 9 in MPEC 2017-Y51 -- 2017 XM1, 2017 XJ60, 2017 XE2, 2017 XC1, 2017 WR28, 2017 WJ14, 2017 WH14, 2017 WG1, 2017 VD2
J04ESA Optical Ground Station in the Canary Islands, 1 in MPEC 2017-Y51 -- 1627
G96Mt. Lemmon Survey (MLS) in Arizona, 18 in MPEC 2017-Y51 -- 2017 VX14, 2017 VU14, 2017 SS19, 2017 RH15, 2015 XK351, 2015 FO124, 1997 GC32, 495959, 259802, 220839, 189700, 171576, 154652, 14402, 140158, 138013, 136745, 7977
D29Purple Mtn. Obs. Xuyi Station in China, 1 in MPEC 2017-Y51 -- 228587
L04ROASTERR-1 in Romania, 1 in MPEC 2017-Y51 -- 2007 XP3
W881Tony Evans in Portugal via Slooh.com Chile Obs. in Chile, 1 in MPEC 2017-Y51 -- 2017 VT14
291Spacewatch 1.8m telescope in Arizona, 6 in MPEC 2017-Y51 -- 2017 VT, 2017 UZ4, 2008 EL, 2004 BG86, 234145, 216985
V78Spirit Marsh Obs. in Minnesota, 2 in MPEC 2017-Y51 -- 3200, 3122
T12UH/Tholen NEO Follow-Up 2.24m Telescope in Hawaii, 2 in MPEC 2017-Y51 -- 2016 EG86, 2015 VE105
For a list of all participating observatories that have Web addresses, see A/CC's Observatory Links page.

Impact Risk Monitoring  on 22 December '17

Summary Risk Table for Risk Assessments Updated Today   (last checks: NEODyS at 1922 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
2016 EG86JPL Sentry1703R E M O V E DJPL: Risk listing removed at 1551 UTC today

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 22 December '17

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

1854Generated Traffic Report
1703Noted that JPL Sentry has removed 2016 EG86 as an impact risk - see above
Grabbed MPEC 2017-Y51 - Daily Orbit Update - see above