Contents  on 3 June '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 3 June '18

One object reported inside ten LD

One minor object started the day just barely within ten LD, at 9.95 LD, and now we are without known visitors until 2018 EJ4 arrives inside ten LD tomorrow.

Neighborhood Traffic
Earth passage I D ~Size Distance today  Inside ten LD Notes
6.10 LD May 29 2018 KN2 27 m  9.95 to 3.34 LD May 30 - June 6 exits ten LD
Approaching (sorted by 10-LD bubble entry date)
5.56 LD June 10 2018 EJ4 186 m  10.97 from 12.19 LD tomorrow - June 16 radar/NHATS target - DOU
8.96 LD June 11 2015 DP155 162 m  11.46 from 12.09 LD June 6 - 15 NHATS target - DOU

This report was generated at 2142 UTC with follow-up in today's DOU MPEC for approaching objects 2018 EJ4 and 2015 DP155 and departed 2018 KT2. The NEOCP object ZLAF9B2 and possible impactor mentioned here yesterday has now been designated 2018 LA (MPEC) and, yes, it did hit, exploding high over southern Botswana but reported mostly from witnesses and cameras in northern South Africa. From infrasound data, Peter Brown puts the object's width at about two meters. This is the third small asteroid since 2008 caught by telescope before Earth impact -- all of them discovered with the same Arizona Catalina Sky Survey (CSS) telescope by professional CSS-team astronomer Richard Kowalski who, as an amateur twenty years ago started the Minor Planet Mailing List (MPML). And the MPML has been lively today with discussion, new information, and work at refining the available data about the big event. See, for instance this thread. Watch A/CC's links page for more info as we get it.
        The many programming scripts used to create these pages expect a minor object, if it enters our ten-LD traffic reporting sphere, to leave. And, if it doesn't leave, some major exceptions have to be handled. We haven't had the opportunity to work on these problems for more than four years, and we don't yet have things working smoothly. That's why the delay in posting today's report, and there may be more delays.
        Update at 2318 UTC:  NASA/JPL has posted a news item about this event.

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 3 June '18

The MPC's NEO Confirmation Page has 16 listings

When last checked at 2358 UTC today, the Minor Planet Center's Near Earth Object discovery Confirmation Page (NEOCP) had sixteen objects listed. Of these, nine were "one nighters." So far The Tracking News has counted a total of eighteen 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 3 June '18

Minor Planet Electronic Circulars

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

MPEC 2018-L04 - "16:15 UT" - 2018 LA

MPC comment: "This object no longer exists (in its original form), following its entry into the Earth's atmosphere on 2018 June 2... [The orbit shown,] based on only the given astrometric observations, indicates that the object reached 50-km height above the Earth's surface around 16:51 UTC over southern Africa."

<< DOU on 3 June '18 >>  MPEC 2018-L03 - "12:02 UT" - Daily Orbit Update

Observers  on 3 June '18

A total of 21 observers appear in today's MPECs.

CodeObserver / observatory
H21Astronomical Research Obs. Westfield in Illinois, 18 in MPEC 2018-L03 -- 2018 KX1, 2018 KV, 2018 KS2, 2018 KQ1, 2018 KM1, 2018 KC3, 2018 JY1, 2018 JS1, 2018 JQ1, 2018 JJ2, 2018 JH2, 2018 JG2, 2018 JF2, 2018 JE5, 2018 JC3, 2018 GA5, 2017 WH14, 504711
T05ATLAS Haleakala in Hawaii, 7 in MPEC 2018-L03 -- 2018 EJ4, 66391, 164201, 163243, 15745, 152931, 1627
T08ATLAS Mauna Loa in Hawaii, 10 in MPECs 2018-L03 & 2018-L04 -- 2018 LA, 475967, 405212, 374851, 36183, 242643, 164121, 5646, 1685, 1036
703Catalina Sky Survey (CSS) in Arizona, 9 in MPEC 2018-L03 -- 2015 DP155, 85989, 53110, 337228, 259802, 138847, 9856, 6455, 1866
G58Chabot Obs. in northern California, 4 in MPEC 2018-L03 -- 2018 JY1, 2018 JQ1, 2018 JJ2, 2018 JE5
595Farra d'Isonzo Obs. in Italy, 3 in MPEC 2018-L03 -- 2018 EJ4, 2015 DP155, 467309
J95Great Shefford Obs. in England, 1 in MPEC 2018-L03 -- 2018 EJ4
238Grorudalen Obs. in Norway, 1 in MPEC 2018-L03 -- 66391
A17Guidestar Obs. in Germany, 6 in MPEC 2018-L03 -- 2018 KC3, 2018 JY1, 2018 JE5, 2018 GA5, 139345, 138847
Z43Landehen Obs., 1 in MPEC 2018-L03 -- 2015 DP155
G96Mt. Lemmon Survey (MLS) in Arizona, 10 in MPECs 2018-L03 & 2018-L04 -- 2018 LA, 2018 KM2, 2018 JA3, 2016 CX264, 88263, 508796, 141531, 136839, 5604, 1685
0895N.V. Maigurova via Nikolaev Obs. in Ukraine, 5 in MPEC 2018-L03 -- 2018 HV2, 2018 EJ4, 2010 WC9, 66391, 212359
I41Palomar Transient Factory in southern California, 1 in MPEC 2018-L03 -- 514652
F51Pan-STARRS 1 (PS1) in Hawaii, 5 in MPEC 2018-L03 -- 2018 JE1, 2011 LY2, 220839, 214088, 186822
104San Marcello Pistoiese Obs. in Italy, 1 in MPEC 2018-L03 -- 2018 EJ4
H36Sandlot Obs. in Kansas, 1 in MPEC 2018-L03 -- 2018 JD2
691Spacewatch 0.9m telescope in Arizona, 18 in MPEC 2018-L03 -- 2018 KT2, 2018 KQ1, 2018 KM2, 2018 KG1, 2018 KC3, 2018 JY1, 2018 JV2, 2018 JS2, 2018 JQ1, 2018 JE5, 2018 HS3, 2018 GX4, 2018 EQ4, 2017 XH62, 2017 KU34, 2003 KW16, 162854, 162635
291Spacewatch 1.8m telescope in Arizona, 8 in MPEC 2018-L03 -- 2018 KR, 2018 KP1, 2018 KP, 2018 JW1, 2018 JO1, 2018 JD5, 2018 GL, 2015 JY1
W34Squirrel Valley Obs. in North Carolina, 2 in MPEC 2018-L03 -- 2018 EJ4, 15745
I52Steward Obs. Mt. Lemmon Station in Arizona, 12 in MPECs 2018-L03 & 2018-L04 -- 2018 LA, 2018 KQ1, 2018 KM1, 2018 KL2, 2018 KF3, 2018 KD3, 2018 KB1, 2018 JE5, 2018 JD5, 2018 HS3, 2018 GL1, 2018 EQ4
T12UH/Tholen NEO Follow-Up 2.24m Telescope in Hawaii, 1 in MPEC 2018-L03 -- 2018 JK3
For a list of all participating observatories that have Web addresses, see A/CC's Observatory Links page.

Impact Risk Monitoring  on 3 June '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 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.





Notes for Today's Latest Risk Assessments
2017 TA6NEODyS1601R E M O V E D-

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 3 June '18

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

2142Generated Traffic Report
1711Grabbed MPEC 2018-L04 - 2018 LA - see above
1601Noted that NEODyS has removed 2017 TA6 as an impact risk - see above
Grabbed MPEC 2018-L03 - Daily Orbit Update - see above