13 Sep '07 Major News

Contents on 13 September '07

Minor-Object News -- two items
Minor-Object Science -- four papers
IAU Minor Planet Center
- NEOCP Activity -- 16 listings: 6 new, 10 updated
- New MPECs -- ten MPECs
- Observers -- 31 observing facilities
Impact Risk Monitoring -- six objects reported
Chronology

Resources:

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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 this year 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.

Minor-Object News on 13 September '07

"Aurigid Shower Dazzles Airborne Observers," Peter Jenniskens/SETI Inst. 13 Sept. - Quote: "The event was caused by the fortuitous collision of Earth with the ever-wandering dust trail of comet C/1911 N1 (Kiess), a potential Earth impactor... Daytime observers in Europe, the eastern USA, and Brazil detected the presence of the shower from reflected radio signals [with] many long-lasting overdense echoes during a 1.5-hour period." {permalink}
"Meteorite Chunk Sale Could Go Sky High," CBS/AP at WCBS-TV 13 Sept. - Quote: "A 28-pound ... chunk of the Willamette meteorite, the largest meteorite ever discovered in North America, is being offered at Bonhams auction house... Its pre-sale estimate is between $1.1 million and $1.3 million." {permalink}

Minor-Object Science on 13 September '07

"Albedos and diameters of three Mars Trojan asteroids" by Trilling, D.E. with A.S. Rivkin, J.A. Stansberry & 3 others, abstract & PDF at arXiv.org 13 Sept. - Quote: "We observed the Mars Trojan asteroids (5261) Eureka and (101429) 1998 VF31 and the candidate Mars Trojan 2001 FR127 at 11.2 and 18.1 microns using Michelle on the Gemini North telescope. We derive diameters of 1.28, 0.78, and <0.52 km, respectively, with corresponding geometric visible albedos of 0.39, 0.32, and >0.14. The albedos for Eureka and 1998 VF31 are consistent with the taxonomic classes and compositions (S(I)/angritic and S(VII)/achrondritic, respectively) and implied histories presented in a companion paper by Rivkin et al. Eureka's surface likely has a relatively high thermal inertia, implying a thin regolith that is consistent with predictions and the small size that we derive." {permalink}
"Composition of the L5 Mars Trojans: Neighbors, not Siblings" by Rivkin, Andrew S. with David E. Trilling, Cristina A. Thomas & 3 others, abstract & PDF at arXiv.org 13 Sept. - Quote: "Mars is the only terrestrial planet known to have Trojan (co-orbiting) asteroids, with a confirmed population of at least 4 objects. The origin of these objects is not known; while several have orbits that are stable on solar-system timescales, work by Rivkin et al. (2003) showed they have compositions that suggest separate origins from one another. We have obtained infrared (0.8-2.5 micron) spectroscopy of the two largest L5 Mars Trojans, and confirm and extend the results of Rivkin et al. (2003). We suggest that the differentiated angrite meteorites are good spectral analogs for 5261 Eureka, the largest Mars Trojan. Meteorite analogs for 101429 1998 VF31 are more varied and include primitive achondrites and mesosiderites." {permalink}
"Thermal Waves in Irradiated Protoplanetary Disks" by Watanabe, Sei-ichiro with D.N.C. Lin, abstract & PDF at arXiv.org 13 Sept. - Quote: "We show that, in disks with modest mass accretion rates, thermal waves are spontaneously and continually excited in the outer disk, propagate inward through the planet-forming domains, and dissipated at small radii where viscous dissipation is dominant." {permalink}
"Discovery of Gas Accretion Onto Stars in 13 Myr old h and chi Persei" by Currie, Thayne with Scott Kenyon, Zoltan Balog & 2 others, abstract & PDF at arXiv.org 13 Sept. - Quote: "We report the discovery of accretion disks associated with ~13 Myr-old intermediate/low-mass stars in h and chi Persei... The existence of accreting pre-main sequence stars in h and chi Persei implies that circumstellar gas in some systems, especially those with primaries later than G5 spectral type, can last longer than 10-15 Myr." {permalink}

NEOCP Activity on 13 September '07

The MPC's NEO Confirmation Page has 16 listings: 6 new, 10 updated

When last checked at 2356 UTC today, the Minor Planet Center's NEO discovery Confirmation Page (NEOCP) had six new and ten updated listings. Of these, eleven were "one nighters." So far Major News has counted a total of 37 objects listed on the NEOCP at some point today.

To learn how observers use the NEOCP, see the Practical guide on how to observe NEOCP object by Birtwhistle et al. at Suno Observatory.

New MPECs on 13 September '07

Minor Planet Electronic Circulars

As of last check at 2356 UTC, there have been ten MPECs issued today from the International Astronomical Union's Minor Planet Center in Cambridge, Massachusetts.

MPEC 2007-R62 time-stamped "06:08 UT" - Daily Orbit Update - see below
MPEC 2007-R63 time-stamped "15:57 UT" - 2004 DM44 - see below
MPEC 2007-R64 time-stamped "16:53 UT" - 2007 RP12 - see below
MPEC 2007-R65 time-stamped "16:56 UT" - 2007 RQ12 - see below
MPEC 2007-R66 time-stamped "16:59 UT" - 2007 RR12 - see below
MPEC 2007-R67 time-stamped "17:01 UT" - 2007 RS12 - see below
MPEC 2007-R68 time-stamped "17:04 UT" - 2007 RT12 - see below
MPEC 2007-R69 time-stamped "17:06 UT" - 2007 RU12 - see below
MPEC 2007-R70 time-stamped "17:12 UT" - 2007 RV12 - see below
MPEC 2007-R71 time-stamped "20:14 UT" - 2007 RP15

MPEC 2007-R71 - "20:14 UT" - 2007 RP15

K07R15P 2007 RP15 (small asteroid, H=23.0 ~85m) was discovered at 0535 UT 13 Sept. by LINEAR, which observed it at Sept. 13.23-28p5. The discovery was confirmed by Remanzacco Obs. (Sept. 13.81-82p3) and Farra d'Isonzo Obs. (Sept. 13.82-83p3).

MPEC 2007-R70 - "17:12 UT" - 2007 RV12

K07R12V 2007 RV12 (small asteroid, Earth MOID=5.6 LD, H=25.7 ~25m) was discovered at 1123 UT 12 Sept. by the Catalina Sky Survey (CSS), which observed it at Sept. 12.47-50p8. The discovery was confirmed by the Mt. Lemmon Survey (MLS) (Sept. 13.49-50p4).

MPEC 2007-R69 - "17:06 UT" - 2007 RU12

K07R12U 2007 RU12 (H=19.7 ~389m) was discovered at 1023 UT 12 Sept. by CSS, which observed it at Sept. 12.43-49p8. The discovery was confirmed by Naef Obs. (Sept. 12.97-99p3), Jim Young via Table Mtn. Obs. (Sept. 13.46-48p4), and McDonald Obs. (Sept. 13.46-48p3).

MPEC 2007-R68 - "17:04 UT" - 2007 RT12

K07R12T 2007 RT12 (risk-listed, H=23.8 ~59m) was discovered at 0909 UT 12 Sept. by MLS, which observed it at Sept. 12.38-45p8 and 13.39-41p4. The discovery was confirmed by the Spacewatch 1.8m telescope (Sept. 13.34-35p3).

MPEC 2007-R67 - "17:01 UT" - 2007 RS12

K07R12S 2007 RS12 (small asteroid, H=23.2 ~78m) was discovered at 0906 UT 12 Sept. by MLS, which observed it at Sept. 12.38-45p8 and 13.39-45p8. The discovery was confirmed by Spacewatch 1.8m (Sept. 13.36-38p3).

MPEC 2007-R66 - "16:59 UT" - 2007 RR12

K07R12R 2007 RR12 (H=19.7 ~389m) was discovered at 0743 UT 12 Sept. by CSS, which observed it at Sept. 12.32-42p12. The discovery was confirmed by Guidestar Obs. (Sept. 12.84-85p3), Eschenberg Obs. (Sept. 13.02p3), South Obs. (Sept. 13.05-06p5), Schiaparelli Obs. (Sept. 13.10-11p3), Powell Obs. (Sept. 13.30-31p4), Young/Table Mtn. (Sept. 13.40-41p4), and McDonald Obs. (Sept. 13.43-44p3).

MPEC 2007-R65 - "16:56 UT" - 2007 RQ12

K07R12Q 2007 RQ12 (small asteroid, Earth MOID=0.6 LD, H=23.6 ~65m) was discovered at 0958 UT 11 Sept. by the Siding Spring Survey (SSS), which observed it at Sept. 11.42-44p4, 11.51-52p4, 12.58p5, and 13.45p3. The discovery was confirmed by Hibiscus Obs. (Sept. 12.23-24p5).

MPEC 2007-R64 - "16:53 UT" - 2007 RP12

K07R12P 2007 RP12 (small asteroid, H=24.5 ~43m) was discovered at 0746 UT 11 Sept. by MLS, which observed it at Sept. 11.32-34p4 and 11.41-44p4. The discovery was confirmed by Schiaparelli Obs. (Sept. 12.03p1), Farpoint Obs. (Sept. 12.21-22p3), Astronomical Research Obs. (ARO) (Sept. 12.25-26p3), Young/Table Mtn. (Sept. 12.35-36p4), Spacewatch 1.8m (Sept. 12.37-38p3 & 13.29-30p3), Great Shefford Obs. (Sept. 13.05-09p3), and Lulin Minor Bodies Tracking (LIMIT) (Sept. 13.59p2).

MPEC 2007-R63 - "15:57 UT" - 2004 DM44

K04D44M 2004 DM44 (Q=4.238 AU, H=20.7 ~245m) from MLS (Sept. 12.27-34p8), Guidestar Obs. (Sept. 12.88-91p3), Great Shefford Obs. (Sept. 12.94-95p3), Powell Obs. (Sept. 13.11-12p4), CEAMIG-REA (Sept. 13.12-13p3), McDonald Obs. (Sept. 13.27-28p3), and Young/Table Mtn. (Sept. 13.34-36p4)

<< DOU on 13 Sept. '07 >> MPEC 2007-R62 - "06:08 UT" - Daily Orbit Update

Observations of risk-listed objects
K07R09V 2007 RV9 (arc=2 days, H=20.0 ~339m) from MLS (Sept. 12.23-25p4)
K07R09U 2007 RU9 (arc=2 days, H=20.8 ~234m) from Spacewatch 1.8m (Sept. 12.36p3)
K07R09T 2007 RT9 (arc=2 days, H=18.6 ~645m) from MLS (Sept. 12.30-31p4)
K07R09R 2007 RR9 (Q=4.738 AU, arc=2 days, H=20.3 ~295m) from Spacewatch 1.8m (Sept. 12.33-35p3)
K07R02F 2007 RF2 (arc=7 days, H=20.6 ~257m) from Stia Obs. (Sept. 11.90-92p4), Greiner Research Obs. (Sept. 12.23-24p6), and Petit Jean Mtn. South Obs. (PJMSO) (Sept. 12.39-40p7)
Observations of recently (no longer) risk-listed objects
K07R01J 2007 RJ1 (small asteroid, arc=10 days, H=25.2 ~31m) from Stia Obs. (Sept. 11.78-80p5), Madonna di Dossobuono Obs. (Sept. 11.86-87p3), PJMSO (Sept. 12.37-38p10), Herrenberg Obs. (Sept. 12.85-86p9), and Great Shefford Obs. (Sept. 12.92p3)
Observations of small asteroids (H>22.0)
K07R09Y 2007 RY9 (arc=2 days, H=23.2 ~78m) from Eschenberg Obs. (Sept. 12.85p3)
K07R08Z 2007 RZ8 (arc=3 days, H=24.1 ~51m) from Spacewatch 1.8m (Sept. 12.43-44p3)
K07R08Y 2007 RY8 (arc=3 days, H=25.3 ~29m) from MLS (Sept. 12.30-31p3)
K07R08X 2007 RX8 (arc=4 days, H=24.5 ~43m) from MLS (Sept. 12.41-42p3)
K07R01H 2007 RH1 (arc=9 days, H=22.6 ~102m) from Stia Obs. (Sept. 11.89-90p4)
K07R01G 2007 RG1 (arc=9 days, H=25.9 ~22m) from Spacewatch 1.8m (Sept. 12.41-42p3)
Observations of other objects
K07R05F 2007 RF5 (arc=7 days, H=18.5 ~676m) from CSS (Sept. 12.47-49p4)
K07R01D 2007 RD1 (arc=11 days, H=21.6 ~162m) from Stia Obs. (Sept. 11.86-87p5), PJMSO (Sept. 12.32-33p6), and Herrenberg Obs. (Sept. 12.87-88p4)
K07Q03E 2007 QE3 (Q=4.081 AU, arc=21 days, H=19.9 ~355m) from Greiner Research Obs. (Sept. 12.25-26p4)
K07Q02K 2007 QK2 (arc=22 days, H=20.6 ~257m) from PJMSO (Sept. 12.27p2)
K07Q02A 2007 QA2 (arc=23 days, H=20.7 ~245m) from Madonna di Dossobuono Obs. (Sept. 6.86-87p3)
K07P11U 2007 PU11 (Q=4.384 AU, arc=3 opp, H=16.3 ~1.86 km) from Greiner Research Obs. (Sept. 12.22p4) and PJMSO (Sept. 12.39p6)
K07P08E 2007 PE8 (arc=121 days, H=19.4 ~446m) from New Millennium Obs. (Sept. 8.85-92p6), Madonna di Dossobuono Obs. (Sept. 8.91-92p3), PJMSO (Sept. 12.30-31p6), and Herrenberg Obs. (Sept. 12.83-84p7)
K07O00V 2007 OV (arc=58 days, H=19.2 ~490m) from Purple Mtn. Obs. XuYi Station (Sept. 11.66-70p4), Greiner Research Obs. (Sept. 12.23p4), and PJMSO (Sept. 12.38p6)
K07L32R 2007 LR32 (arc=110 days, H=17.2 ~1.23 km) from New Millennium Obs. (Sept. 8.87-94p6), Madonna di Dossobuono Obs. (Sept. 8.92-93p2), Greiner Research Obs. (Sept. 12.21-22p6), PJMSO (Sept. 12.31p6), and Remanzacco Obs. (Sept. 12.79-82p3)
K07L00V 2007 LV (arc=2 opp, H=18.1 ~812m) from SSS (Sept. 12.59-62p3)
K07H15E 2007 HE15 (arc=143 days, H=19.6 ~407m) from PJMSO (Sept. 12.33-34p6)
K07G03S 2007 GS3 (arc=155 days, H=19.3 ~467m) from the FTP education program via Faulkes Telescope North (Sept. 11.57p3) and Eschenberg Obs. (Sept. 13.04-05p2)
K04X14P 2004 XP14 (arc=2 opp, H=19.4 ~446m) from Spacewatch 1.8m (Sept. 13.12-13p3)
K04O11T 2004 OT11 (arc=3 opp, H=17.3 ~1.17 km) from PJMSO (Sept. 12.21p1)
K04K01E 2004 KE1 (arc=2 opp, H=21.6 ~162m) from SSS (Sept. 12.63-64p4)
K03O14R 2003 OR14 (arc=4 opp, H=16.4 ~1.78 km) from Madonna di Dossobuono Obs. (Sept. 8.89-90p3) and PJMSO (Sept. 12.24p2)
K03E54F 2003 EF54 (arc=6 opp, H=20.0 ~339m) from CSS (Sept. 12.29-31p4)
K03B47T 2003 BT47 (arc=3 opp, H=17.5 ~1.07 km) from the Spacewatch 0.9m telescope (Sept. 12.42-46p3)
K02RC9T 2002 RT129 (arc=2 opp, H=19.5 ~426m) from MLS (Sept. 12.40-42p4)
K02N04N 2002 NN4 (arc=4 opp, H=20.0 ~339m) from Remanzacco Obs. (Sept. 12.81-83p3)
K02E06M 2002 EM6 (arc=2 opp, H=20.1 ~323m) from CSS (Sept. 12.15-16p4)
K00R37W 2000 RW37 (arc=3 opp, H=20.0 ~339m) from PJMSO (Sept. 12.35-36p5)
K00Q07T 2000 QT7 (arc=2 opp, H=20.0 ~339m) from Tentlingen Obs. (Sept. 11.89p1 & 11.93p1)
J99J03U 1999 JU3 (arc=4 opp, H=19.3 ~467m) from PJMSO (Sept. 12.26p5)
J98S15D 1998 SD15 (arc=4 opp, H=18.9 ~562m) from PJMSO (Sept. 12.28p6) and Eschenberg Obs. (Sept. 12.79p3)
J93G00D 1993 GD (arc=4 opp, H=20.8 ~234m) from Spacewatch 1.8m (Sept. 13.16p3)
E5656 145656 4788 P-L from PJMSO (Sept. 12.24-25p5)
D8883 138883 2000 YL29 from MLS (Sept. 12.16-17p4)
A0756 100756 1998 FM5 from Purple Mtn. Obs. XuYi Station (Sept. 11.56-59p4)
86324 86324 1999 WA2 from PJMSO (Sept. 12.20p5)
16636 16636 1993 QP from New Millennium Obs. (Sept. 8.85-87p3 & 8.91p2)
05786 5786 Talos (1991 RC) from Purple Mtn. Obs. XuYi Station (Sept. 11.56-59p4)

Observers on 13 September '07

A total of 31 observing facilities appear in today's MPECs.

Code	Observer / observatory
`H55`	Astronomical Research Obs. in Illinois, 1 in MPEC 2007-R64 -- 2007 RP12
`I77`	CEAMIG-REA in Brazil, 1 in MPEC 2007-R63 -- 2004 DM44
`703`	Catalina Sky Survey in Arizona, 6 in MPECs 2007-R62, 2007-R66, 2007-R69 & 2007-R70 -- 2007 RV12, 2007 RU12, 2007 RR12, 2007 RF5, 2003 EF54, 2002 EM6
`151`	Eschenberg Obs. in Switzerland, 4 in MPECs 2007-R62 & 2007-R66 -- 2007 RY9, 2007 RR12, 2007 GS3, 1998 SD15
`734`	Farpoint Obs. in Kansas, 1 in MPEC 2007-R64 -- 2007 RP12
`595`	Farra d'Isonzo Obs. in Italy, 1 in MPEC 2007-R71 -- 2007 RP15
`F653`	FTP education program via Faulkes Telescope North in Hawaii, 1 in MPEC 2007-R62 -- 2007 GS3
`J95`	Great Shefford Obs. in England, 3 in MPECs 2007-R62, 2007-R63 & 2007-R64 -- 2007 RP12, 2007 RJ1, 2004 DM44
`H51`	Greiner Research Obs. in Wisconsin, 5 in MPEC 2007-R62 -- 2007 RF2, 2007 QE3, 2007 PU11, 2007 OV, 2007 LR32
`A17`	Guidestar Obs. in Germany, 2 in MPECs 2007-R63 & 2007-R66 -- 2007 RR12, 2004 DM44
`240`	Herrenberg Obs. in Germany, 3 in MPEC 2007-R62 -- 2007 RJ1, 2007 RD1, 2007 PE8
`F84`	Hibiscus Obs. in Tahiti, 1 in MPEC 2007-R65 -- 2007 RQ12
`704`	LINEAR in New Mexico, 1 in MPEC 2007-R71 -- 2007 RP15
`D35`	Lulin Minor Bodies Tracking in Taiwan, 1 in MPEC 2007-R64 -- 2007 RP12
`560`	Madonna di Dossobuono Obs. in Italy, 5 in MPEC 2007-R62 -- 2007 RJ1, 2007 QA2, 2007 PE8, 2007 LR32, 2003 OR14
`711`	McDonald Obs. in Texas, 3 in MPECs 2007-R63, 2007-R66 & 2007-R69 -- 2007 RU12, 2007 RR12, 2004 DM44
`G96`	Mt. Lemmon Survey in Arizona, 11 in MPECs 2007-R62, 2007-R63, 2007-R64, 2007-R67, 2007-R68 & 2007-R70 -- 2007 RY8, 2007 RX8, 2007 RV9, 2007 RV12, 2007 RT9, 2007 RT12, 2007 RS12, 2007 RP12, 2004 DM44, 2002 RT129, 138883
`A13`	Naef Obs. in Switzerland, 1 in MPEC 2007-R69 -- 2007 RU12
`A24`	New Millennium Obs. in Italy, 3 in MPEC 2007-R62 -- 2007 PE8, 2007 LR32, 16636
`H45`	Petit Jean Mtn. South Obs. in Arkansas, 16 in MPEC 2007-R62 -- 2007 RJ1, 2007 RF2, 2007 RD1, 2007 QK2, 2007 PU11, 2007 PE8, 2007 OV, 2007 LR32, 2007 HE15, 2004 OT11, 2003 OR14, 2000 RW37, 1999 JU3, 1998 SD15, 86324, 145656
`649`	Powell Obs. in Kansas, 2 in MPECs 2007-R63 & 2007-R66 -- 2007 RR12, 2004 DM44
`D29`	Purple Mtn. Obs. XuYi Station in China, 3 in MPEC 2007-R62 -- 2007 OV, 100756, 5786
`473`	Remanzacco Obs. in Italy, 3 in MPECs 2007-R62 & 2007-R71 -- 2007 RP15, 2007 LR32, 2002 NN4
`204`	Schiaparelli Obs. in Italy, 2 in MPECs 2007-R64 & 2007-R66 -- 2007 RR12, 2007 RP12
`E12`	Siding Spring Survey in New South Wales, 3 in MPECs 2007-R62 & 2007-R65 -- 2007 RQ12, 2007 LV, 2004 KE1
`J84`	South Obs. in England, 1 in MPEC 2007-R66 -- 2007 RR12
`691`	Spacewatch 0.9m telescope in Arizona, 1 in MPEC 2007-R62 -- 2003 BT47
`291`	Spacewatch 1.8m telescope in Arizona, 9 in MPECs 2007-R62, 2007-R64, 2007-R67 & 2007-R68 -- 2007 RZ8, 2007 RU9, 2007 RT12, 2007 RS12, 2007 RR9, 2007 RP12, 2007 RG1, 2004 XP14, 1993 GD
`A78`	Stia Obs. in Italy, 4 in MPEC 2007-R62 -- 2007 RJ1, 2007 RH1, 2007 RF2, 2007 RD1
`6735`	Jim Young via Table Mtn. Obs. in southern California, 4 in MPECs 2007-R63, 2007-R64, 2007-R66 & 2007-R69 -- 2007 RU12, 2007 RR12, 2007 RP12, 2004 DM44
`A16`	Tentlingen Obs. in Switzerland, 1 in MPEC 2007-R62 -- 2000 QT7

Impact Risk Monitoring on 13 September '07

**Summary Risk Table for Risk Assessments Updated Today** (last checks: NEODyS and JPL at 2356 UTC)
See the CRT page for a list of all objects rated recently as risks.
Note that the time horizon for JPL is 100 years from today and for NEODyS is now usually the year 2090.
For the latest official risk assessments, and for explanations of the terminology, see the JPL NEO Program Sentry and NEODyS CLOMON (backup) 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

2007 RV9	JPL	1421	2011-2106	187	3.9e-07	-3.40	-3.66	0	JPL: "Analysis based on 15 observations spanning 1.9611 days (2007-Sep-10.28811 to 2007-Sep-12.24924)." Diameter approximately 0.344 km. from mean, weighted H=20.0.
2007 RV9	NEODyS	1421	2011-2089	97	1.92e-07	-3.51	-3.74	0	NEODyS: "Based on 15 optical observations (of which 0 are rejected as outliers) from 2007/09/10.289 to 2007/09/12.250."

2007 RU9	JPL	1421	2013-2105	55	4.2e-06	-2.50	-2.71	0	JPL: "Analysis based on 26 observations spanning 2.0776 days (2007-Sep-10.28596 to 2007-Sep-12.36356)." Diameter approximately 0.231 km. from mean, weighted H=20.8.
2007 RU9	NEODyS	1421	2013-2086	56	3.55e-06	-2.56	-2.78	0	NEODyS: "Based on 28 optical observations (of which 2 are rejected as outliers) from 2007/09/10.287 to 2007/09/12.364."

2007 RT12	JPL	2055	2015-2073	25	1.2e-08	-7.12	-7.50	0	JPL: "Analysis based on 15 observations spanning 1.0317 days (2007-Sep-12.38131 to 2007-Sep-13.41303)." Diameter approximately 0.058 km. from mean, weighted H=23.8.

2007 RT9	JPL	1421	2028-2105	27	2.3e-08	-5.13	-5.86	0	JPL: "Analysis based on 19 observations spanning 2.0284 days (2007-Sep-10.28434 to 2007-Sep-12.31272)." Diameter approximately 0.351 km. from mean, weighted H=19.9.
2007 RT9	NEODyS	1421	2022-2088	47	3.35e-08	-4.91	-5.86	0	NEODyS: "Based on 19 optical observations (of which 0 are rejected as outliers) from 2007/09/10.285 to 2007/09/12.313."

2007 RR9	JPL	1421	R E M O V E D						JPL: Risk listing removed at 1251 UTC.
2007 RR9	NEODyS	1421	R E M O V E D

2007 RF2	JPL	1421	R E M O V E D						JPL: Risk listing removed at 0958 UTC.

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 an 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" for more about this.

Chronology on 13 September '07

Times are UTC for when the items were noted or added by Major News.

2055	Noted that JPL has posted 2007 RT12 as an impact risk - see above Grabbed MPEC 2007-R71 - 2007 RP15 - see above
1731	Grabbed MPEC 2007-R70 - 2007 RV12 - see above
1712	Grabbed MPEC 2007-R64 - 2007 RP12 - see above Grabbed MPEC 2007-R65 - 2007 RQ12 - see above Grabbed MPEC 2007-R66 - 2007 RR12 - see above Grabbed MPEC 2007-R67 - 2007 RS12 - see above Grabbed MPEC 2007-R68 - 2007 RT12 - see above Grabbed MPEC 2007-R69 - 2007 RU12 - see above
1711	Added link to news story, "Meteorite Chunk Sale Could Go Sky High" - see above Added link to news story, "Aurigid Shower Dazzles Airborne Observers" - see above
1631	Grabbed MPEC 2007-R63 - 2004 DM44 - see above
1425	Added MOS paper, "Albedos and diameters of three Mars Trojan asteroids" - see above Added MOS paper, "Composition of the L5 Mars Trojans: Neighbors, not Siblings" - see above Added MOS paper, "Discovery of Gas Accretion Onto Stars in 13 Myr old h and chi Persei" - see above Added MOS paper, "Thermal Waves in Irradiated Protoplanetary Disks" - see above
1421	Noted that JPL has removed 2007 RF2 as an impact risk - see above Noted that JPL has removed 2007 RR9 as an impact risk - see above Noted that NEODyS has removed 2007 RR9 as an impact risk - see above Noted that JPL has posted 2007 RT9 as an impact risk - see above Noted that NEODyS has updated its 2007 RT9 risk assessment - see above Noted that JPL has updated its 2007 RU9 risk assessment - see above Noted that NEODyS has updated its 2007 RU9 risk assessment - see above Noted that JPL has posted 2007 RV9 as an impact risk - see above Noted that NEODyS has updated its 2007 RV9 risk assessment - see above Grabbed MPEC 2007-R62 - Daily Orbit Update - see above

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