Hubble Space Telescope view of double asteroid/comet 288P/2006 VW139 
from 22 Aug. 2016. Credit: HST, NASA, ESA & J. Agarwal.

The Space Telescope Science Institute has a news item about Hubble Space Telescope observations from last August and September of double asteroid 300163 2006 VW139, also known as unnamed Main Belt comet 288P. Image credit: HST, NASA, ESA, and J. Agarwal (Max Planck Inst. for Solar System Research).


Contents  on 21 September '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 21 September '17

Eight objects reported inside ten LD

There are eight asteroidal objects reported to be inside ten lunar distances (LD) of our home world today. The two closest are receding intruders. 2017 SR2 starts the day inside the Earth-Moon system at 0.40 LD and ends at 2.50 LD, beyond Earth's sphere of gravitational influence (SOI). And 2017 SM2 began its day within one LD of the Moon on its way out to 3.28 LD from our planet by day's end.

Earth passage I D ~Size Distance Today  Notes
0.24 LD yesterday2017 SR2 6 m  0.40 to 2.50 LD intruder today, exits Earth SOI, Moon closest 1.02 LD at 0252 UTC - DOU
0.81 LD yesterday2017 SM2 12 m  1.53 to 3.28 LD intruder, exits Earth SOI
2.45 LD Sept. 172017 RK2 9 m  5.91 to 7.51 LD risk - DOU
4.39 LD Sept. 252017 RO16 8 m  7.69 from 9.09 LD
5.76 LD tomorrow2017 RB15 10 m  5.86 from 6.17 LD
6.18 LD Sept. 182017 RX2 17 m  8.95 to 11.16 LD exits ten LD
6.79 LD Sept. 182017 RU2 24 m  7.99 to 9.19 LD risk - DOU
7.85 LD Sept. 192017 RG2 45 m  8.19 to 8.91 LD DOU

This report was generated at 1914 UTC with additional observation of 2017 SR2 and first follow-up for 2017 RK2 in today's DOU MPEC along with continuing follow-up for five more objects in the active traffic tables here plus three departed objects: radar target 2017 CS and risk-listed objects 2017 RV2 and 2017 QS16.

Approaching (sorted by 10-LD bubble entry date)
9.70 LD tomorrow2017 RQ15 24 m  < 10 LD tomorrow - DOU
4.76 LD Sept. 262017 RB16 25 m  < 10 LD tomorrow
7.87 LD Sept. 291989 VB 389 m  < 10 LD Sept. 25, radar target - DOU
0.13 LD Oct. 122012 TC4 15 m  < 10 LD Oct. 5, intruder, radar/NHATS target, risk - DOU
8.5   LD Oct. 132005 TE49 15 m  < 10 LD Oct. 11, uncertainty +/- 10.1167 hours, NHATS target
5.77 LD Oct. 22171576 1999 VP11 645 m  < 10 LD Oct. 20



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 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 21 September '17

The MPC's NEO Confirmation Page has 91 listings

When last checked at 2358 UTC today, the Minor Planet Center's Near Earth Object discovery Confirmation Page (NEOCP) had 91 objects listed. Of these, 48 were "one nighters." So far The Tracking News has counted a total of 95 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 21 September '17

Minor Planet Electronic Circulars

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


MPEC 2017-S95 - "13:26 UT" - 2015 BF4


MPEC 2017-S94 - "13:23 UT" - 2012 CQ36


<< DOU on 21 Sept. '17 >>  MPEC 2017-S93 - "12:04 UT" - Daily Orbit Update


MPEC 2017-S92 - "11:39 UT" - 2013 TF6


MPEC 2017-S91 - "11:32 UT" - 2014 WP202

Observers  on 21 September '17

A total of 33 observers appear in today's MPECs.

CodeObserver / observatory
H21Astronomical Research Obs. Westfield in Illinois, 13 in MPEC 2017-S93 -- 2017 QF17, 2017 QE2, 2017 QC3, 2017 OJ68, 2017 OG1, 2017 NV5, 2017 KD5, 2017 HQ49, 2017 CS, 486692, 365246, 225416, 163051
T05ATLAS Haleakala in Hawaii, 2 in MPEC 2017-S93 -- 294739, 153415
T08ATLAS Mauna Loa in Hawaii, 13 in MPEC 2017-S93 -- 2004 TD10, 1993 RA, 96631, 66146, 53319, 495858, 416584, 411201, 223456, 21374, 162566, 141670, 11405
B66Casasco Obs. in Italy, 1 in MPEC 2017-S93 -- 3122
703Catalina Sky Survey (CSS) in Arizona, 28 in MPEC 2017-S93 -- 2017 RW1, 2017 RV1, 2017 QQ32, 2017 QL18, 2017 PS25, 2017 MY3, 2001 UQ163, 96631, 90075, 66146, 53319, 52762, 496018, 416584, 411201, 355770, 338176, 265962, 250458, 190166, 162186, 162117, 141874, 137799, 100926, 7336, 5143, 1980
J27El Guijo Obs. in Spain, 4 in MPEC 2017-S93 -- 2017 RV1, 2017 OP68, 2004 TQ13, 190166
J04ESA Optical Ground Station (ESA OGS) in the Canary Islands, 3 in MPECs 2017-S91, 2017-S94 & 2017-S95 -- 2015 BF4, 2014 WP202, 2012 CQ36
151Eschenberg Obs. in Switzerland, 3 in MPEC 2017-S93 -- 2017 RV1, 2017 QV34, 2004 RE84
203GiaGa Obs. in Italy, 2 in MPEC 2017-S93 -- 2017 RV1, 2017 PR25
A17Guidestar Obs. in Germany, 4 in MPEC 2017-S93 -- 2017 RV2, 2017 QT35, 2017 NL6, 2008 AX28
H15ISON New Mexico Obs. in New Mexico, 2 in MPEC 2017-S93 -- 85628, 329520
Q62|Sergio Foglia in Italy via iTelescope Obs. Siding Spring in New South Wales, 1 in MPEC 2017-S93 -- 1989 VB
J38La Vara Obs. in Spain, 1 in MPEC 2017-S93 -- 3122
W85LCOGT Cerro Tololo A in Chile, 1 in MPEC 2017-S93 -- 2012 TC4
K91LCOGT Sutherland A in South Africa, 1 in MPEC 2017-S93 -- 154590
K93LCOGT Sutherland C in South Africa, 2 in MPEC 2017-S93 -- 2006 TU7, 326354
474Mt. John Obs. in New Zealand, 1 in MPEC 2017-S93 -- 2017 SR2
Z80Northolt Branch Obs. in England, 4 in MPEC 2017-S93 -- 2017 RV1, 2017 RL, 2017 PJ26, 2017 OP68
G34Oberfrauendorf Obs. in Germany, 2 in MPEC 2017-S93 -- 2017 PJ26, 2017 OP68
C23Olmen Obs. in Belgium, 3 in MPEC 2017-S93 -- 2017 RV1, 2017 PR25, 2017 PJ26
F51Pan-STARRS 1 (PS1) in Hawaii, 3 in MPEC 2017-S93 -- 2017 RU2, 2017 FR90, 154589
Z38Picoto Obs., 1 in MPEC 2017-S93 -- 6053
J53Posadas Obs. in Spain, 1 in MPEC 2017-S93 -- 265962
W71Rand II Obs. in New York, 1 in MPEC 2017-S93 -- 2017 RV1
G40!M. Kumrucu-Lohmiller in Massachusetts via Slooh.com Canary Islands Obs. in the Canary Islands, 1 in MPEC 2017-S93 -- 190208
Y00SONEAR in Brazil, 1 in MPEC 2017-S93 -- 495959
691Spacewatch 0.9m telescope in Arizona, 2 in MPEC 2017-S93 -- 2017 RV2, 2017 PC27
291Spacewatch 1.8m telescope in Arizona, 1 in MPEC 2017-S93 -- 2017 QG33
I52Steward Obs. Mt. Lemmon Station in Arizona, 10 in MPEC 2017-S93 -- 2017 RV15, 2017 RQ15, 2017 RL2, 2017 RG15, 2017 QY34, 2017 QL33, 2017 PT25, 2017 OD20, 2017 MK8, 2017 FH90
926Tenagra II Obs. in Arizona, 8 in MPECs 2017-S92 & 2017-S93 -- 2017 RW2, 2017 RW1, 2017 RU2, 2017 RK2, 2017 RG2, 2017 PR25, 2017 MK8, 2013 TF6
Z52The Studios Obs., 2 in MPEC 2017-S93 -- 3122, 1980
T14UH/Tholen NEO Follow-Up CFH Telescope in Hawaii, 2 in MPEC 2017-S93 -- 2017 QS16, 2017 KN34
C51WISE in Earth polar orbit, 2 in MPEC 2017-S93 -- 495858, 444193
For a list of all participating observatories that have Web addresses, see A/CC's Observatory Links page.

Impact Risk Monitoring  on 21 September '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 SQ2NEODyS16202039-209241.54e-07-7.38-7.560NEODyS: "Based on 21 optical observations (of which 0 are rejected as outliers) from 2017-09-18.347 to 2017-09-20.004."
2017 RP16NEODyS16202065-2114235.5e-06-6.54-7.010NEODyS: "Based on 16 optical observations (of which 3 are rejected as outliers) from 2017-09-15.412 to 2017-09-19.372."
2017 RN16NEODyS16202076-21171311.05e-04-6.28-6.80NEODyS: "Based on 9 optical observations (of which 0 are rejected as outliers) from 2017-09-15.406 to 2017-09-18.420."
2017 RH16NEODyS16202040-2117721.08e-05-4.84-4.850NEODyS: "Based on 9 optical observations (of which 0 are rejected as outliers) from 2017-09-13.336 to 2017-09-18.412."
2017 RV2JPL Sentry16202082-2117390.000111057417-4.90-5.700JPL: Computed at 08:47 today Pacific time based on 115 observations spanning 6.9021 days (2017-Sep-14.43497 to 2017-Sep-21.33712). Diameter approximately 0.020 km. from weighted mean H=26.17.
NEODyS16202071-2117547.23e-05-5.08-5.730NEODyS: "Based on 109 optical observations (of which 2 are rejected as outliers) from 2017-09-14.436 to 2017-09-20.251."
2017 RU2JPL Sentry16202093-209315.702e-07-6.92-6.920JPL: Computed at 07:56 today Pacific time based on 51 observations spanning 34.098 days (2017-Aug-17.37701 to 2017-Sep-20.475). Diameter approximately 0.024 km. from weighted mean H=25.76.
NEODyS1620209816.73e-10-9.89-9.890NEODyS: "Based on 37 optical observations (of which 0 are rejected as outliers) from 2017-09-14.420 to 2017-09-19.494."
2017 RK2JPL Sentry16202083-208318.612e-06-6.76-6.760JPL: Computed at 07:56 today Pacific time based on 29 observations spanning 6.1708 days (2017-Sep-13.31727 to 2017-Sep-19.4881). Diameter approximately 0.009 km. from weighted mean H=28.00.

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 21 September '17

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

1914Generated Traffic Report
1620Noted that NEODyS has posted 2017 RH16 as an impact risk - see above
Noted that JPL Sentry has updated its 2017 RK2 risk assessment - see above
Noted that NEODyS has posted 2017 RN16 as an impact risk - see above
Noted that NEODyS has posted 2017 RP16 as an impact risk - see above
Noted that JPL Sentry has updated its 2017 RU2 risk assessment - see above
Noted that NEODyS has posted 2017 RU2 as an impact risk - see above
Noted that JPL Sentry has updated its 2017 RV2 risk assessment - see above
Noted that NEODyS has updated its 2017 RV2 risk assessment - see above
Noted that NEODyS has posted 2017 SQ2 as an impact risk - see above
Grabbed MPEC 2017-S91 - 2014 WP202 - see above
Grabbed MPEC 2017-S92 - 2013 TF6 - see above
Grabbed MPEC 2017-S93 - Daily Orbit Update - see above
Grabbed MPEC 2017-S94 - 2012 CQ36 - see above
Grabbed MPEC 2017-S95 - 2015 BF4 - see above