Contents  on 18 September '13

Asteroid/Comet Connection (A/CC) Resources:

The latest A/CC news is available via framed access, RSS news feed RSS news feed, or redirection. - Note: A/CC has a main Web site and also a backup site with its own duplicate RSS news feed.

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. And use the all-up news archive to access news from any time since A/CC began in early 2002. To keep track of what's new each day, watch the Chronology section.

Traffic Report  on 18 September '13

Five objects reported inside ten LD

There are five visitors reported flying inside ten lunar distances (LD) of Earth today. Tiny risk-listed intruder 2013 RZ53 continues is slow passage between Earth and Moon. 2013 RM73 exits Earth's Hill sphere, going from 3.14 to 4.94 LD. Out further, 2013 RF74 comes its closest to Earth this time around, reaching 5.52 LD at 1652 UT, risk-listed 2013 RS43 is outbound from 6.44 to 7.66 LD, and 2013 RT73 is also headed out, today passing from 8.77 to 9.53 LD.

This report was updated at 2127 UTC with new discovery of already departed 2013 RY80 (MPEC). Today's first traffic report was generated at 1634 UTC with observation of distant 152664 1998 FW4 reported in today's DOU MPEC.

Notes: Ten times the distance to the Moon (ten LD) has no astronomical significance but is a useful reporting boundary. Earth's Hill sphere (of gravitational influence) is estimated to extend out to around 3.89 LD. Object distances are interpreted 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 18 September '13

The MPC's NEO Confirmation Page has 16 listings

When last checked at 2359 UTC today, the Minor Planet Center's Near Earth Object discovery Confirmation Page (NEOCP) had sixteen objects listed. Of these, two 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 18 September '13

Minor Planet Electronic Circulars

As of last check at 2359 UTC, there have been two MPECs posted today from the International Astronomical Union's Minor Planet Center in Cambridge, Massachusetts.

MPEC 2013-S22 - "18:45 UT" - 2013 RY80

<< DOU on 18 Sept. '13 >>  MPEC 2013-S21 - "06:05 UT" - Daily Orbit Update

Observers  on 18 September '13

Sixteen observers appear in today's MPECs.

CodeObserver / observatory
B88Bigmuskie Obs. in Italy, 4 in MPEC 2013-S21 -- 2013 RH74, 2013 QJ10, 2013 OM9, 2001 QC34
160Castelmartini Obs. in Italy, 3 in MPEC 2013-S21 -- 2013 PN43, 2013 OM9, 2013 BO76
703Catalina Sky Survey (CSS) in Arizona, 6 in MPEC 2013-S21 -- 2013 RZ73, 340666, 329437, 251346, 162566, 11398
Z81Estrella de Mar Obs., 2 in MPEC 2013-S21 -- 355256, 17511
J95Great Shefford Obs. in England, 1 in MPEC 2013-S22 -- 2013 RY80
355Hadano Obs. in Japan, 3 in MPEC 2013-S21 -- 368664, 4450, 3691
K38M57 Obs., 1 in MPEC 2013-S21 -- 2013 RX80
5682David Tholen's team on Mauna Kea in Hawaii, 2 in MPEC 2013-S21 -- 2010 LJ14, 2002 XS40
G96Mt. Lemmon Survey (MLS) in Arizona, 4 in MPEC 2013-S21 -- 257838, 163373, 162581, 162566
A24New Millennium Obs. in Italy, 16 in MPEC 2013-S21 -- 2013 QJ10, 2013 PN43, 2013 OM9, 2013 MX5, 2012 TS, 2010 TN54, 2003 OB4, 2001 QC34, 85804, 66008, 355256, 340666, 250620, 162510, 105140, 4183
I41Palomar Transient Factory (PTF) in southern California, 3 in MPEC 2013-S21 -- 355256, 350988, 30825
F51Pan-STARRS 1 in Hawaii, 1 in MPEC 2013-S22 -- 2013 RY80
H45Petit Jean Mtn. South Obs. (PJMSO) in Arkansas, 5 in MPEC 2013-S21 -- 2013 QJ10, 2012 TS, 2010 TN54, 329437, 152664
C95SATINO-1 in France, 1 in MPEC 2013-S21 -- 2013 QL10
B74Santa Maria de Montmagastrell Obs. in Spain, 1 in MPEC 2013-S22 -- 2013 RY80
A92Urseanu Obs. in Romania, 2 in MPEC 2013-S21 -- 361071, 329437
For a list of all participating observatories that have Web addresses, see A/CC's Observatory Links page.

Impact Risk Monitoring  on 18 September '13

Summary Risk Table for Risk Assessments Updated Today   (last checks: NEODyS and JPL at 2359 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 JPL NEO Program Sentry and NEODyS CLOMON2 risk pages.





Notes for Today's Latest Risk Assessments
2013 RJ74NEODyS16332014-210965.13e-08-2.74-2.750NEODyS: "Based on 24 optical observations (of which 0 are rejected as outliers) from 2013-09-14.305 to 2013-09-17.320."
2013 RH74JPL Sentry1633R E M O V E DJPL: Risk listing removed at 1203 UTC.
2009 FZ4JPL Sentry03452014-21103183.3e-06-5.21-5.820JPL: "Analysis based on 11 observations spanning .59999 days (2009-Mar-19.36974 to 2009-Mar-19.96973)." Diameter approximately 0.031 km. from mean, weighted H=25.2.

Legend: VI# = VI count, Prob Cum = cumulative probability, PS Cum/Max = cumulative/maximum Palermo Scale, TS = Torino Scale

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 18 September '13

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

2127Updated Traffic Report
1900Grabbed MPEC 2013-S22 - 2013 RY80 - see above
1633Noted that JPL Sentry has removed 2013 RH74 as an impact risk - see above
Noted that NEODyS has posted 2013 RJ74 as an impact risk - see above
Grabbed MPEC 2013-S21 - Daily Orbit Update - see above
0345Noted that JPL Sentry has updated its 2009 FZ4 risk assessment - see above