Contents  on 25 September '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 25 September '18

Five objects reported inside ten LD

Five minor objects are reported within ten lunar distances (LD) of Earth today. Nearest is 2018 RQ1, which moves outward from 4.06 to 4.12 LD.

Neighborhood Traffic - sorted by Earth passage distance, grouped by 2.41, 5.0 & 10.0 LD boundaries
Earth passage I D ~Size Distance today  Inside ten LD Notes
4.06 LD yesterday 2018 RQ1 51 m  4.06 to 4.12 LD Sept. 11 - Oct. 8 NHATS target
4.30 LD yesterday 2018 ST1 32 m  4.73 to 6.35 LD Sept. 20 - 27 NEW, risk - MPEC
6.51 LD Sept. 27 2018 SS1 65 m  7.46 from 9.45 LD yesterday - Sept. 29
6.80 LD Sept. 27 2018 SM1 93 m  7.04 from 7.46 LD Sept. 21 - Oct. 3 NHATS target
8.57 LD Sept. 22 2018 RH6 11 m  9.02 to 9.53 LD Sept. 19 - 26 NHATS target

This report was generated at 1752 UTC with the discovery of risk-listed outbound 2018 ST1 (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 25 September '18

The MPC's NEO Confirmation Page has 25 listings

When last checked at 2358 UTC today, the Minor Planet Center's Near Earth Object discovery Confirmation Page (NEOCP) had 25 objects listed. Of these, ten were "one nighters." So far The Tracking News has counted a total of 27 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 25 September '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.

<< DOU on 25 Sept. '18 >>  MPEC 2018-S61 - "12:24 UT" - Daily Orbit Update

MPEC 2018-S60 - "10:16 UT" - 2018 ST1

Observers  on 25 September '18

Seven observers appear in today's MPECs.

CodeObserver / observatory
V03Big Water Obs. in Utah, 1 in MPEC 2018-S60 -- 2018 ST1
J95Great Shefford Obs. in England, 1 in MPEC 2018-S60 -- 2018 ST1
J69North Obs. in England, 1 in MPEC 2018-S60 -- 2018 ST1
Z80Northolt Branch Obs. in England, 1 in MPEC 2018-S60 -- 2018 ST1
I41Palomar Transient Factory in southern California, 1 in MPEC 2018-S60 -- 2018 ST1
104San Marcello Pistoiese Obs. in Italy, 1 in MPEC 2018-S60 -- 2018 ST1
C51WISE in Earth polar orbit, 2 in MPEC 2018-S61 -- 2018 PL9, 37336
For a list of all participating observatories that have Web addresses, see A/CC's Observatory Links page.

Impact Risk Monitoring  on 25 September '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
2018 ST1NEODyS1600209018.49e-09-8.32-8.320NEODyS: "Based on 45 optical observations (of which 3 are rejected as outliers) from 2018-09-22.242 to 2018-09-24.957."
2009 FZ4NEODyS16002022-21161624.73e-07-6.31-7.070NEODyS: "Based on 11 optical observations (of which 0 are rejected as outliers) from 2009-03-19.371 to 2009-03-19.970."

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 25 September '18

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

1752Generated Traffic Report
1600Noted that NEODyS has updated its 2009 FZ4 risk assessment - see above
Noted that NEODyS has posted 2018 ST1 as an impact risk - see above
Grabbed MPEC 2018-S60 - 2018 ST1 - see above
Grabbed MPEC 2018-S61 - Daily Orbit Update - see above