Contents  on 19 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 19 December '17

Ten objects reported inside ten LD

Today there are ten visitors known to be within ten lunar distances (LD) of the planet we call home. Nearest is 2017 XY61, which comes its closest to Earth on this passage, reaching 2.51 LD at 0940 UTC.

Earth passage I D ~Size Distance today  Inside ten LD Notes
2.51 LD today 2017 XY61 19 m  2.51 LD Dec. 16 - 22 Earth closest at 0940 UTC
2.88 LD Dec. 22 2017 YE 7 m  3.80 from 4.56 LD Dec. 13 - 31 NEW - MPEC
3.11 LD yesterday 2017 XW61 27 m  3.77 to 5.69 LD Dec. 14 - 21
3.35 LD Dec. 14 2006 XY 54 m  5.90 to 6.83 LD Dec. 5 - 23 NHATS target
3.83 LD Dec. 17 2017 VT14 80 m  5.90 to 7.83 LD Dec. 13 - 21 radar target, comet nucleus?
4.51 LD Dec. 15 2017 XY2 13 m  8.18 to 9.75 LD Dec. 10 - 20 NHATS target, risk
5.16 LD yesterday 2017 XW60 8 m  5.52 to 6.48 LD Dec. 13 - 22
7.61 LD Dec. 24 2017 WZ14 31 m  9.30 from 9.97 LD yesterday - Dec. 30 radar/NHATS target
7.94 LD Dec. 17 2017 XT60 11 m  8.12 to 8.60 LD Dec. 14 - 21
8.15 LD yesterday 2017 XX61 16 m  8.26 to 9.48 LD Dec. 16 - 20
Approaching (sorted by 10-LD bubble entry date)
3.7   LD Feb. 24* 2017 DR109 10 m  148.7 from 151.8 LD Feb. 18 - March 1 EPU +/- 30 mins.*, NHATS target
3.8   LD March 7* 2017 VR12 265 m  108.2 from 110.0 LD Feb. 28 - March 13 EPU +/- 15 mins.*, radar/NHATS target
* EPU = Earth passage uncertainty

This report was generated at 1821 UTC with the discovery of inbound 2017 YE (see the active traffic table above) and with follow-up in today's DOU MPEC for departed 2017 XS along with astrometry from earlier this month for 2017 VD.

Reading:  Queen's University Belfast has a news item about a "letter" in the journal Nature yesterday (also available today at arXiv.org) explaining why 1I/`Oumuamua (A/2017 U1) (links) could be an inactive comet nucleus. "[It] has been shown that cosmic-ray irradiation of organic ices, plus heating by local supernovae, can produce devolatilised carbon-rich mantles" estimated at about 0.1 to 2 meters in thickness. This could protect an icy object from the disruptive forces of tumbling even with an oddly elongated shape, and could prevent cometary activity despite brief intense heating when this object passed our Sun. Wired has a report on this and more.



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 19 December '17

The MPC's NEO Confirmation Page has 21 listings

When last checked at 2358 UTC today, the Minor Planet Center's Near Earth Object discovery Confirmation Page (NEOCP) had 21 objects listed. Of these, twelve were "one nighters." So far The Tracking News has counted a total of 39 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 19 December '17

Minor Planet Electronic Circulars

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


MPEC 2017-Y45 - "19:40 UT" - Comet C/2017 X1 (Panstarrs)


MPEC 2017-Y44 - "18:46 UT" - Comet P/2017 W3 (Gibbs)


MPEC 2017-Y43 - "16:46 UT" - Comet C/2017 W2 (Leonard)


MPEC 2017-Y42 - "15:33 UT" - 2013 XZ21


MPEC 2017-Y41 - "15:03 UT" - 2017 XE62


MPEC 2017-Y40 - "14:59 UT" - 2017 XC62


MPEC 2017-Y39 - "14:56 UT" - 2017 XA62


MPEC 2017-Y38 - "14:52 UT" - 2017 YE


MPEC 2017-Y37 - "14:48 UT" - 2017 YD


MPEC 2017-Y36 - "14:43 UT" - 2017 XJ62


MPEC 2017-Y35 - "14:39 UT" - 2017 XH62


MPEC 2017-Y34 - "14:34 UT" - 2017 XG62


MPEC 2017-Y33 - "14:30 UT" - 2017 XF62


MPEC 2017-Y32 - "14:25 UT" - 2017 XD62


MPEC 2017-Y31 - "14:16 UT" - 2017 XB62


<< DOU on 19 Dec. '17 >>  MPEC 2017-Y30 - "13:05 UT" - Daily Orbit Update

Observers  on 19 December '17

A total of 54 observers appear in today's MPECs.

CodeObserver / observatory
H21Astronomical Research Obs. Westfield in Illinois, 17 in MPECs 2017-Y30, 2017-Y32, 2017-Y37 & 2017-Y41 -- 2017 YD, 2017 XE62, 2017 XD62, 2017 WY, 2017 WX12, 2017 WW27, 2017 WS1, 2017 WG2, 2017 VX14, 2017 VK1, 2017 VD, 2017 SP19, 2017 SO17, 2017 NL6, 168378, 10165, 8567
T08ATLAS Mauna Loa in Hawaii, 7 in MPECs 2017-Y30, 2017-Y34 & 2017-Y36 -- 2017 XL2, 2017 XJ62, 2017 XG62, 2017 WX12, 2017 QL33, 2007 KE, 504887
C77Bernezzo Obs. in Italy, 2 in MPECs 2017-Y34 & 2017-Y36 -- 2017 XJ62, 2017 XG62
Z84Calar Alto Schmidt in Spain, 1 in MPEC 2017-Y41 -- 2017 XE62
160Castelmartini Obs. in Italy, 8 in MPECs 2017-Y30, 2017-Y34 & 2017-Y36 -- 2017 XJ62, 2017 XG62, 53430, 504680, 17182, 16657, 137805, 1980
703Catalina Sky Survey (CSS) in Arizona, 2 in MPECs 2017-Y33 & 2017-Y44 -- 2017 XF62, P/2017 W3
V06Catalina Sky Survey Kuiper Telescope in Arizona, 1 in MPEC 2017-Y43 -- C/2017 W2
807|Robert Holmes in Illinois via Cerro Tololo Inter-American Obs. (CTIO) in Chile, 6 in MPECs 2017-Y31, 2017-Y33, 2017-Y35, 2017-Y37, 2017-Y38 & 2017-Y45 -- 2017 YE, 2017 YD, 2017 XH62, 2017 XF62, 2017 XB62, C/2017 X1
A77Chante-Perdrix Obs. in France, 3 in MPECs 2017-Y30, 2017-Y43 & 2017-Y44 -- P/2017 W3, C/2017 W2, 3200
850Cordell-Lorenz Obs. in Tennessee, 2 in MPECs 2017-Y36 & 2017-Y43 -- 2017 XJ62, C/2017 W2
W84"program code '"' (11) via DECam in Chile, 2 in MPEC 2017-Y30 -- 2014 DN112, 2005 JU108
113Drebach Obs. in Germany, 2 in MPECs 2017-Y34 & 2017-Y36 -- 2017 XJ62, 2017 XG62
J04ESA Optical Ground Station (ESA OGS) in the Canary Islands, 8 in MPECs 2017-Y30, 2017-Y31, 2017-Y33, 2017-Y37, 2017-Y38 & 2017-Y42 -- 2017 YE, 2017 YD, 2017 XS2, 2017 XO2, 2017 XF62, 2017 XB62, 2017 VW13, 2013 XZ21
595Farra d'Isonzo Obs. in Italy, 3 in MPECs 2017-Y34, 2017-Y36 & 2017-Y43 -- 2017 XJ62, 2017 XG62, C/2017 W2
157Frasso Sabino Obs. in Italy, 2 in MPECs 2017-Y34 & 2017-Y36 -- 2017 XJ62, 2017 XG62
K88GINOP-KHK in Hungary, 3 in MPECs 2017-Y32, 2017-Y34 & 2017-Y36 -- 2017 XJ62, 2017 XG62, 2017 XD62
J95Great Shefford Obs. in England, 6 in MPECs 2017-Y33, 2017-Y34, 2017-Y35, 2017-Y36, 2017-Y38 & 2017-Y41 -- 2017 YE, 2017 XJ62, 2017 XH62, 2017 XG62, 2017 XF62, 2017 XE62
511Haute Provence Obs. in Germany, 1 in MPEC 2017-Y34 -- 2017 XG62
857Iowa Robotic Obs. in Arizona, 1 in MPEC 2017-Y30 -- 3200
U69#program code "#" (12) via iTelescope Obs. Auberry in northern California, 1 in MPEC 2017-Y44 -- P/2017 W3
U695Hidetaka Sato in Japan via iTelescope Obs. Auberry in northern California, 2 in MPECs 2017-Y43 & 2017-Y44 -- P/2017 W3, C/2017 W2
I89.B. Lutkenhoner in Germany via iTelescope Obs. Nerpio in Spain, 1 in MPEC 2017-Y30 -- 3200
Q621Hidetaka Sato in Japan via iTelescope Obs. Siding Spring in New South Wales, 1 in MPEC 2017-Y45 -- C/2017 X1
695@program code "@" (41) via Kitt Peak Natl. Obs. in Arizona, 1 in MPEC 2017-Y30 -- 3200
W87LCO Cerro Tololo C in Chile, 3 in MPECs 2017-Y31, 2017-Y44 & 2017-Y45 -- 2017 XB62, C/2017 X1, P/2017 W3
K91LCO Sutherland A in South Africa, 1 in MPEC 2017-Y31 -- 2017 XB62
Z21LCO Tenerife Aqawan A#1 in the Canary Islands, 1 in MPEC 2017-Y44 -- P/2017 W3
K38M57 Obs. in Italy, 1 in MPEC 2017-Y34 -- 2017 XG62
H01Magdalena Ridge Obs. (MRO) in New Mexico, 5 in MPECs 2017-Y33, 2017-Y37, 2017-Y38, 2017-Y40 & 2017-Y41 -- 2017 YE, 2017 YD, 2017 XF62, 2017 XE62, 2017 XC62
568_Marco Micheli on Mauna Kea in Hawaii, 1 in MPEC 2017-Y45 -- C/2017 X1
G96Mt. Lemmon Survey (MLS) in Arizona, 9 in MPECs 2017-Y32, 2017-Y35, 2017-Y37, 2017-Y38, 2017-Y39, 2017-Y40, 2017-Y41, 2017-Y43 & 2017-Y44 -- 2017 YE, 2017 YD, 2017 XH62, 2017 XE62, 2017 XD62, 2017 XC62, 2017 XA62, P/2017 W3, C/2017 W2
C47Nonndorf Obs. in Austria, 2 in MPECs 2017-Y30 & 2017-Y34 -- 2017 XG62, 3200
Z80Northolt Branch Obs. in England, 1 in MPEC 2017-Y30 -- 2017 WX12
G34Oberfrauendorf Obs. in Germany, 1 in MPEC 2017-Y30 -- 140158
J43Oukaimeden Obs. in Morocco, 2 in MPEC 2017-Y30 -- 505667, 8567
F51Pan-STARRS 1 (PS1) in Hawaii, 4 in MPECs 2017-Y30, 2017-Y31, 2017-Y38 & 2017-Y45 -- 2017 YE, 2017 XB62, C/2017 X1, 415029
K63Pascoli Obs. in Italy, 3 in MPECs 2017-Y34, 2017-Y36 & 2017-Y38 -- 2017 YE, 2017 XJ62, 2017 XG62
J53Posadas Obs. in Spain, 1 in MPEC 2017-Y30 -- 163696
V83Rolling Hills Obs. in Missouri, 1 in MPEC 2017-Y30 -- 3200
L07Salvatore di Giacomo Obs., 1 in MPEC 2017-Y36 -- 2017 XJ62
104San Marcello Pistoiese Obs. in Italy, 3 in MPECs 2017-Y34, 2017-Y36 & 2017-Y38 -- 2017 YE, 2017 XJ62, 2017 XG62
H36Sandlot Obs. in Kansas, 1 in MPEC 2017-Y35 -- 2017 XH62
204Schiaparelli Obs. in Italy, 4 in MPECs 2017-Y32, 2017-Y36, 2017-Y38 & 2017-Y41 -- 2017 YE, 2017 XJ62, 2017 XE62, 2017 XD62
033Schwarzschild Obs. in Germany, 2 in MPECs 2017-Y36 & 2017-Y43 -- 2017 XJ62, C/2017 W2
G40"G. Gasparovic in Croatia via Slooh.com Canary Islands Obs. in the Canary Islands, 1 in MPEC 2017-Y44 -- P/2017 W3
587Sormano Obs. in Italy, 6 in MPECs 2017-Y32, 2017-Y34, 2017-Y36, 2017-Y37, 2017-Y38 & 2017-Y41 -- 2017 YE, 2017 YD, 2017 XJ62, 2017 XG62, 2017 XE62, 2017 XD62
691Spacewatch 0.9m telescope in Arizona, 20 in MPECs 2017-Y30, 2017-Y31, 2017-Y33, 2017-Y35, 2017-Y37, 2017-Y40, 2017-Y41, 2017-Y43, 2017-Y44 & 2017-Y45 -- 2017 YD, 2017 XT61, 2017 XS, 2017 XL60, 2017 XH62, 2017 XF62, 2017 XE62, 2017 XC62, 2017 XB62, 2017 XB1, C/2017 X1, 2017 WY12, 2017 WU13, P/2017 W3, C/2017 W2, 2017 SS19, 2017 RV1, 2017 RH15, 2006 OC5, 2003 YX1
291Spacewatch 1.8m telescope in Arizona, 12 in MPECs 2017-Y30, 2017-Y31 & 2017-Y38 -- 2017 YE, 2017 XS2, 2017 XC2, 2017 XB62, 2017 WY, 2017 WN28, 2017 VE15, 2017 NK, 2017 HT2, 2015 CZ, 2007 LF, 2005 WS3
V78Spirit Marsh Obs. in Minnesota, 1 in MPEC 2017-Y30 -- 3200
I52Steward Obs. Mt. Lemmon Station in Arizona, 13 in MPECs 2017-Y31, 2017-Y32, 2017-Y33, 2017-Y34, 2017-Y35, 2017-Y36, 2017-Y38, 2017-Y39, 2017-Y40, 2017-Y41, 2017-Y43, 2017-Y44 & 2017-Y45 -- 2017 YE, 2017 XJ62, 2017 XH62, 2017 XG62, 2017 XF62, 2017 XE62, 2017 XD62, 2017 XC62, 2017 XB62, 2017 XA62, C/2017 X1, P/2017 W3, C/2017 W2
J22Tacande Obs. in the Canary Islands, 1 in MPEC 2017-Y44 -- P/2017 W3
926Tenagra II Obs. in Arizona, 8 in MPECs 2017-Y33, 2017-Y34, 2017-Y35, 2017-Y36, 2017-Y38, 2017-Y39, 2017-Y43 & 2017-Y44 -- 2017 YE, 2017 XJ62, 2017 XH62, 2017 XG62, 2017 XF62, 2017 XA62, P/2017 W3, C/2017 W2
T12UH/Tholen NEO Follow-Up 2.24m Telescope in Hawaii, 1 in MPEC 2017-Y30 -- 2008 RT26
L01Visnjan Obs., 2 in MPECs 2017-Y34 & 2017-Y37 -- 2017 YD, 2017 XG62
718Wiggins Obs. in Utah, 1 in MPEC 2017-Y36 -- 2017 XJ62
For a list of all participating observatories that have Web addresses, see A/CC's Observatory Links page.

Impact Risk Monitoring  on 19 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 XS2JPL Sentry18022104-211688.36985678e-05-5.08-5.120JPL: Computed at 09:43 today Pacific time based on 19 observations spanning 8.0200 days (2017-Dec-11.35957 to 2017-Dec-19.37958). Diameter approximately 0.020 km. from weighted mean H=26.17.
2017 XO2JPL Sentry17302039-2111838.3931478e-06-3.75-4.050JPL: Computed at 09:16 today Pacific time based on 25 observations spanning 8.5621 days (2017-Dec-10.33601 to 2017-Dec-18.898139). Diameter approximately 0.110 km. from weighted mean H=22.46.
2017 XC2JPL Sentry1700R E M O V E DJPL: Risk listing removed at 1648 UTC today
2017 VW13JPL Sentry17002097-209722.5961e-06-3.72-3.770JPL: Computed at 08:51 today Pacific time based on 194 observations spanning 35.436 days (2017-Nov-13.64011 to 2017-Dec-19.076247). Diameter approximately 0.250 km. from weighted mean H=20.63.
2005 TM173JPL Sentry17002018-21161539.459091e-07-5.38-6.270JPL: Computed at 08:06 April 8th Pacific time based on 6 observations spanning 1.9467 days (2005-Oct-09.20072 to 2005-Oct-11.14743). Diameter approximately 0.051 km. from weighted mean H=24.12.

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 19 December '17

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

2000Grabbed MPEC 2017-Y45 - Comet C/2017 X1 (Panstarrs) - see above
1900Grabbed MPEC 2017-Y44 - Comet P/2017 W3 (Gibbs) - see above
1821Generated Traffic Report
1802Noted that JPL Sentry has updated its 2017 XS2 risk assessment - see above
1730Noted that JPL Sentry has updated its 2017 XO2 risk assessment - see above
1700Noted that JPL Sentry has updated its 2005 TM173 risk assessment - see above
Noted that JPL Sentry has updated its 2017 VW13 risk assessment - see above
Noted that JPL Sentry has removed 2017 XC2 as an impact risk - see above
Grabbed MPEC 2017-Y43 - Comet C/2017 W2 (Leonard) - see above
1620Grabbed MPEC 2017-Y30 - Daily Orbit Update - see above
Grabbed MPEC 2017-Y31 - 2017 XB62 - see above
Grabbed MPEC 2017-Y32 - 2017 XD62 - see above
Grabbed MPEC 2017-Y33 - 2017 XF62 - see above
Grabbed MPEC 2017-Y34 - 2017 XG62 - see above
Grabbed MPEC 2017-Y35 - 2017 XH62 - see above
Grabbed MPEC 2017-Y36 - 2017 XJ62 - see above
Grabbed MPEC 2017-Y37 - 2017 YD - see above
Grabbed MPEC 2017-Y38 - 2017 YE - see above
Grabbed MPEC 2017-Y39 - 2017 XA62 - see above
Grabbed MPEC 2017-Y40 - 2017 XC62 - see above
Grabbed MPEC 2017-Y41 - 2017 XE62 - see above
Grabbed MPEC 2017-Y42 - 2013 XZ21 - see above