Contents  on 28 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 28 December '17

Ten objects reported inside ten LD

Bulletin - 2332, upeated 2348 UTC:  Two new discoveries of close passers have been announced. These will be added to the next traffic report, after we obtain and process further details.

Earth passageI D~SizeInside ten LD approx.Notes
6.03 LD at 0053 tomorrow2017 YB610 m Dec. 25 - Jan. 1MPEC
9.61 LD at 1616 Dec. 202017 YC622 m Dec. 19 - 22MPEC


Today ten visitors are known to be less than ten lunar distances (LD) from Earth. By far the nearest is intruder 2017 YZ4, which passed the Moon at 0.68 LD at 0837 UTC and went by us at 0.58 LD at 1549 UTC. Of the other nine, only 2017 YU1 is inbound, moving in from 8.68 to 8.05 LD. Everything else is headed away.

Earth passage I D ~Size Distance today  Inside ten LD Notes
0.58 LD today 2017 YZ4 9 m  0.58 LD Dec. 23 - Jan. 2 intruder today, NHATS target, Moon closest 0.68 LD
at 0837 UTC, Earth closest at 1549 UTC - DOU
1.77 LD Dec. 15 2017 YD1 3 m  8.04 to 8.69 LD Nov. 30 - Dec. 31 NHATS target, risk
1.93 LD Dec. 24 2017 YS1 6 m  3.11 to 3.71 LD Dec. 11 - Jan. 7 NHATS target
2.24 LD yesterday 2017 YD2 6 m  2.79 to 4.18 LD Dec. 21 - Jan. 1 NHATS target, risk
2.88 LD Dec. 22 2017 YE 7 m  6.56 to 7.51 LD Dec. 13 - 31 NHATS target
4.84 LD Dec. 19 2017 YW3 17 m  7.25 to 7.76 LD Dec. 5 - Jan. 1 NHATS target
5.13 LD Dec. 26 2017 YQ1 41 m  8.55 to 12.68 LD Dec. 24 - 28 exits ten LD
7.62 LD Dec. 24 2017 WZ14 32 m  8.34 to 8.84 LD Dec. 18 - 30 radar/NHATS target
7.74 LD Dec. 30 2017 YU1 20 m  8.05 from 8.68 LD Dec. 26 - Jan. 3 NHATS target
8.47 LD Dec. 25 2017 YR3 29 m  9.19 to 9.86 LD Dec. 21 - 29 NHATS target
Approaching (sorted by 10-LD bubble entry date)
3.7   LD Feb. 24* 2017 DR109 10 m  121.5 from 124.4 LD Feb. 18 - March 1 EPU +/- 30 mins.*, NHATS target
3.8   LD March 7* 2017 VR12 272 m  93.3 from 94.8 LD Feb. 28 - March 13 EPU +/- 5 mins.*, radar/NHATS target
* EPU = Earth passage uncertainty

This report was generated at 1924 UTC with first follow-up in today's DOU MPEC for passing 2017 YZ4, departed 2017 XN60 (12.04 days added to 2.02-day discovery arc), and departed risk-listed 2017 YO5, along with continuing follow-up for departed 2017 YT1, 2017 YH1, and 2017 WJ13, plus astrometry from September for 2017 SB12 and 2017 SS10.



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 28 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, 57 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 28 December '17

Minor Planet Electronic Circulars

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


MPEC 2017-Y138 - "23:05 UT" - 2017 YB6


MPEC 2017-Y137 - "23:01 UT" - 2017 YC6


MPEC 2017-Y136 - "22:58 UT" - 2017 YA6


MPEC 2017-Y135 - "22:54 UT" - 2017 YZ5


MPEC 2017-Y134 - "22:50 UT" - 2017 YY5


MPEC 2017-Y133 - "22:46 UT" - 2017 YX5


MPEC 2017-Y132 - "22:42 UT" - 2017 YW5


MPEC 2017-Y131 - "22:38 UT" - 2017 YV5


MPEC 2017-Y130 - "22:35 UT" - 2017 YU5


MPEC 2017-Y129 - "22:31 UT" - 2017 YT5


<< DOU on 28 Dec. '17 >>  MPEC 2017-Y128 - "13:05 UT" - Daily Orbit Update

Observers  on 28 December '17

A total of 23 observers appear in today's MPECs.

CodeObserver / observatory
H21Astronomical Research Obs. Westfield in Illinois, 26 in MPECs 2017-Y128, 2017-Y135, 2017-Y136, 2017-Y137 & 2017-Y138 -- 2017 YZ5, 2017 YC6, 2017 YB6, 2017 YA6, 2017 XN60, 2017 XD62, 2017 XB1, 2017 WF13, 2017 VX14, 2017 VN15, 2017 TC4, 2017 SX19, 2017 ST19, 2017 SS10, 2017 SQ21, 2017 SH10, 2017 SB12, 2017 RG15, 2017 QN33, 2017 QC3, 2017 OD20, 2017 KY34, 2010 NG3, 500922, 499582, 3360
T08ATLAS Mauna Loa in Hawaii, 1 in MPEC 2017-Y128 -- 2016 AU8
703Catalina Sky Survey in Arizona, 1 in MPEC 2017-Y128 -- 2017 YH1
V06Catalina Sky Survey Kuiper Telescope in Arizona, 1 in MPEC 2017-Y130 -- 2017 YU5
807|Robert Holmes in Illinois via Cerro Tololo Inter-American Obs. (CTIO) in Chile, 2 in MPECs 2017-Y129 & 2017-Y131 -- 2017 YV5, 2017 YT5
J95Great Shefford Obs. in England, 5 in MPECs 2017-Y128, 2017-Y135 & 2017-Y138 -- 2017 YZ5, 2017 YZ4, 2017 YL5, 2017 YK5, 2017 YB6
Z22MASTER IAC Obs. in the Canary Islands, 1 in MPEC 2017-Y128 -- 475967
568_Marco Micheli on Mauna Kea in Hawaii, 3 in MPECs 2017-Y130, 2017-Y131 & 2017-Y133 -- 2017 YX5, 2017 YV5, 2017 YU5
711McDonald Obs. in Texas, 2 in MPECs 2017-Y129 & 2017-Y135 -- 2017 YZ5, 2017 YT5
G96Mt. Lemmon Survey (MLS) in Arizona, 34 in MPECs 2017-Y128, 2017-Y134, 2017-Y135, 2017-Y136, 2017-Y137 & 2017-Y138 -- 2017 YZ5, 2017 YY5, 2017 YO5, 2017 YC6, 2017 YB6, 2017 YA6, 2017 XV2, 2017 XG2, 2017 TX3, 2017 SL2, 2015 XZ261, 2015 RL82, 2015 KJ57, 2014 QW296, 2014 QS439, 2013 XF22, 2004 LU3, 2004 CL1, 2003 YP3, 506859, 506459, 490354, 456973, 386847, 262623, 228587, 219527, 164221, 154300, 153814, 101873, 8037, 3671, 2062
J69North Obs. in England, 2 in MPECs 2017-Y128 & 2017-Y136 -- 2017 YH1, 2017 YA6
F51Pan-STARRS 1 (PS1) in Hawaii, 5 in MPECs 2017-Y129, 2017-Y130, 2017-Y131, 2017-Y132 & 2017-Y133 -- 2017 YX5, 2017 YW5, 2017 YV5, 2017 YU5, 2017 YT5
B49Paus Obs. in Spain, 1 in MPEC 2017-Y128 -- 2017 YP5
H36Sandlot Obs. in Kansas, 2 in MPECs 2017-Y134 & 2017-Y136 -- 2017 YY5, 2017 YA6
G40(program code "(" (17) via Slooh.com Canary Islands Obs. in the Canary Islands, 1 in MPEC 2017-Y136 -- 2017 YA6
W881Tony Evans in Portugal via Slooh.com Chile Obs. in Chile, 1 in MPEC 2017-Y128 -- 2017 VU14
691Spacewatch 0.9m telescope in Arizona, 5 in MPECs 2017-Y128, 2017-Y132 & 2017-Y137 -- 2017 YZ1, 2017 YW5, 2017 YC6, 2017 XD62, 2017 UZ4
291Spacewatch 1.8m telescope in Arizona, 8 in MPECs 2017-Y128, 2017-Y129, 2017-Y130, 2017-Y131, 2017-Y132 & 2017-Y133 -- 2017 YX5, 2017 YW5, 2017 YV5, 2017 YU5, 2017 YT5, 2017 WS12, 2017 WJ13, 2017 SN14
W34Squirrel Valley Obs. in North Carolina, 1 in MPEC 2017-Y128 -- 2017 XL2
I52Steward Obs. Mt. Lemmon Station in Arizona, 16 in MPECs 2017-Y128, 2017-Y131, 2017-Y133, 2017-Y134, 2017-Y135, 2017-Y136, 2017-Y137 & 2017-Y138 -- 2017 YZ5, 2017 YY5, 2017 YX5, 2017 YV5, 2017 YT3, 2017 YT1, 2017 YO1, 2017 YK1, 2017 YC6, 2017 YB6, 2017 YA6, 2017 XP60, 2017 XC2, 2017 XC, 2017 WF13, 2017 VA2
926Tenagra II Obs. in Arizona, 5 in MPECs 2017-Y130, 2017-Y131, 2017-Y132, 2017-Y134 & 2017-Y138 -- 2017 YY5, 2017 YW5, 2017 YV5, 2017 YU5, 2017 YB6
T12UH/Tholen NEO Follow-Up 2.24m Telescope in Hawaii, 1 in MPEC 2017-Y128 -- 2016 EH157
C51WISE in Earth polar orbit, 3 in MPEC 2017-Y128 -- 333888, 154347, 1036
For a list of all participating observatories that have Web addresses, see A/CC's Observatory Links page.

Impact Risk Monitoring  on 28 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 YP5JPL Sentry17002070-207012.693e-08-6.49-6.490JPL: Computed at 08:27 today Pacific time based on 33 observations spanning 2.3632 days (2017-Dec-25.51022 to 2017-Dec-27.87346). Diameter approximately 0.096 km. from weighted mean H=22.73.
2017 YO5NEODyS17302067-2117217.57e-06-5.93-6.640NEODyS: "Based on 22 optical observations (of which 4 are rejected as outliers) from 2017-12-25.453 to 2017-12-27.431."
JPL Sentry17002084-2117158.723556e-06-5.94-6.500JPL: Computed at 08:38 today Pacific time based on 26 observations spanning 3.0042 days (2017-Dec-25.45197 to 2017-Dec-28.45614). Diameter approximately 0.021 km. from weighted mean H=26.08.
2017 YE5NEODyS1730211615.02e-07-3.43-3.430NEODyS: "Based on 21 optical observations (of which 0 are rejected as outliers) from 2017-12-21.007 to 2017-12-27.403."
2017 YZ1JPL Sentry17002024-2117597.9623749e-06-2.93-3.000JPL: Computed at 08:02 today Pacific time based on 27 observations spanning 8.0723 days (2017-Dec-20.42481 to 2017-Dec-28.49716). Diameter approximately 0.220 km. from weighted mean H=20.89.

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 28 December '17

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

2330Grabbed MPEC 2017-Y137 - 2017 YC6 - see above
Grabbed MPEC 2017-Y138 - 2017 YB6 - see above
2300Grabbed MPEC 2017-Y129 - 2017 YT5 - see above
Grabbed MPEC 2017-Y130 - 2017 YU5 - see above
Grabbed MPEC 2017-Y131 - 2017 YV5 - see above
Grabbed MPEC 2017-Y132 - 2017 YW5 - see above
Grabbed MPEC 2017-Y133 - 2017 YX5 - see above
Grabbed MPEC 2017-Y134 - 2017 YY5 - see above
Grabbed MPEC 2017-Y135 - 2017 YZ5 - see above
Grabbed MPEC 2017-Y136 - 2017 YA6 - see above
1924Generated Traffic Report
1730Noted that NEODyS has posted 2017 YE5 as an impact risk - see above
Noted that NEODyS has posted 2017 YO5 as an impact risk - see above
1700Noted that JPL Sentry has updated its 2017 YO5 risk assessment - see above
Noted that JPL Sentry has updated its 2017 YP5 risk assessment - see above
Noted that JPL Sentry has updated its 2017 YZ1 risk assessment - see above
Grabbed MPEC 2017-Y128 - Daily Orbit Update - see above