Sunday12 September 20047:23pm MDT2004-09-13 UTC 0123 last
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small object 2004 QB3 
caught 3 Sept. 2004 at Jornada Obs.

The Asteroid/Comet Connection's
daily news journal about
asteroids, comets, and meteors

Today's issue status: done


Cover: This composite, manipulated at A/CC from a FITS file provided by David Dixon at Jornada Observatory in New Mexico, shows faint small object 2004 QB3 on September 3rd (report). The image, he writes, is “cropped from a stack of forty 50-second images. [The] NEO was moving about 1.9 arcsec./min. and was at about 21.8V in magnitude. The telescope I used is a Meade 0.4 m SCT that has been the primary instrument at Jornada for about two years. This May I sent the Apogee Instruments CCD camera that had been on the telescope back to Apogee to have it rebuilt as one of their new Alta models with a much faster digitization and download speed, and is working out nicely for track-and-stack astrometry.

Small objects – panel 1/2 Major News for 12 Sept. 2004 back top next  

Small objects
Discovery & follow-up for 6-12 September 2004

The discoveries of six small asteroids were announced this past week (“small” is defined at right), all found by LINEAR, a Massachusetts operation with telescopes in New Mexico. One of these objects, 2004 RU109, was discovered yesterday morning and will make the sixth closest Earth flyby this year, coming slightly inside the Earth-Moon system at 1542 UTC tomorrow (11:42am EDT). And this, the smallest of asteroids observed this week, was listed today by JPL with six low-rated impact solutions (see below).

As detailed in the following observation summary, three other discoveries flew past at between 14.7 and 18.5 lunar distances, two on the day of their discovery and one two days earlier.

Beginning with the period of 9-15 August, this is the third week that six discoveries were announced, which is the most since mid-June when eight small asteroids were announced. Another three were tracked, including two that were much in need of follow-up, and 17 observing facilities participated in this grand work.

<< previous report | skip table | Small objects table >>

What’s so big about “small objects?” If an asteroid’s orbit brings it to within 0.05 astronomical units (AU) of Earth's orbit, it is categorized as “potentially hazardous” unless it has an absolute magnitude H greater than 22.0, which corresponds to a diameter on the order of 135 meters/yards. Larger H means less bright, thus smaller size. And 0.05 AU is about 19.5 times the distance between Earth and Moon (0.00256 AU). To be discovered and tracked, such objects usually must come close (a few are Earth’s nearest neighbors, coming closer than the Moon). They are exposed pieces of distant asteroid populations, and they have within their own population tomorrow’s meteors. And their discovery and follow-up represents today’s best amateur and professional asteroid observing work. Diameter & Earth MOID: In the following observation summary table, the stated diameters are rough best estimates from a standard but very inexact H-to-size formula using H (absolute magnitude, or brightness) from the JPL NEO Orbital Elements page, source also for Earth MOID (minimum orbital intersection distance). Current Minor Planet Center H is also given, along with the original H from each object's discovery MPEC. Other sources: Planetary MOIDs are from Lowell Observatory. Priorities and visibilities are from the European Spaceguard Central Node (SCN). And flyby distances and times are from the JPL Close Approach Table. See also the Sormano Observatory SAEL (H>22.0 and Earth MOID<0.015 AU), and NEODyS listings have yet another H calculation.
Small objects – panel 2/2 (table) Major News for 12 Sept. 2004 back top next  

Small object observation summary for 6-12 Sept. 2004

H = absolute magnitude (brightness), from which size is roughly estimated   —   m/yd = meters/yards   —   [cross index]
All objects had observations reported last week. Those on a light-blue background had observations from only before the week.

European Spaceguard Central Node
2004 RU109
has VIs
17 m/yd26.4826.426.5 2004-R630.001226 AU   blank = not yet listed
NEW: 2004 RU109 was discovered on 11 Sept. by LINEAR, was confirmed on 11 Sept. by Great Shefford Obs. and KLENOT, and on 12 Sept. by Great Shefford Obs. (1.76 hours after its first observation), Three Buttes Obs., Robert Hutsebaut using a Rent-A-Scope telescope, Grasslands Obs., and Sandlot Obs., and was announced in MPEC 2004-R63 of 12 Sept. It has an MOID of 0.013 AU with Mars, and will pass 0.96 lunar distance (LD) from Earth at 1542 UTC on 13 Sept.
2004 PG20
41 m/yd24.5624.624.6 2004-P370.047714 AUNecessary, visibility ends 19 Sept.
2004 PG20 was observed on 9 Sept. by Linz Obs. Not observed since August 19th (see report), this work added 21.875 days to what had been a 9.681-day observation arc.
2004 RW2
46 m/yd24.3424.524.5 2004-R300.037696 AUUrgent, visibility ends 21 Sept.
NEW: 2004 RW2 flew past Earth at 14.7 LD on 6 Sept., the day it was discovered by LINEAR. The discovery was confirmed that day by KLENOT, and on 7 Sept. by Powell Obs. (reporting 16 positions spanning almost three hours), Table Mountain Obs., LINEAR, Grasslands Obs., and Farpoint Obs., and was announced in MPEC 2004-R30 of 7 Sept. This object was also observed on 7 Sept. by LINEAR and Roeser Obs., and on 8 and 9 Sept. by Great Shefford Obs.
2004 RC80
48 m/yd24.2324.324.6 2004-R510.043497 AU
NEW: 2004 RC80 was discovered on 9 Sept. by LINEAR, the day it flew past Earth at 18.5 LD, was confirmed on 9 Sept. by KLENOT and Great Shefford Obs., and on 10 Sept. by LINEAR, and was announced in MPEC 2004-R51 of 10 Sept. Further Sept. 10th observations from LINEAR were also reported.
2004 RC11
70 m/yd23.4123.623.6 2004-R460.005009 AUNecessary, visibility ends 23 Oct.
NEW: 2004 RC11 was discovered on 8 Sept. by LINEAR, was confirmed on 8 Sept. by KLENOT, and on 9 Sept. by Uccle Obs. and Farpoint Obs., and was announced in MPEC 2004-R46 of 9 Sept. This object was also observed on 9 Sept. by Jim Bedient using a Rent-A-Scope telescope and by Sabino Canyon Obs., on 10 Sept. by Great Shefford Obs., and on 11 Sept. by KLENOT. It has an MOID of 0.022 AU with Mars.
2004 RB11
73 m/yd23.3323.724.0 2004-R450.036578 AUUseful, visibility ends 21 Nov.
NEW: 2004 RB11 flew past Earth at 16.6 LD on Sept. 6th and was discovered on the 8th by LINEAR, was confirmed that day by Gnosca Obs. and KLENOT, and on 9 Sept. by Farpoint Obs. and Sabino Canyon Obs., and was announced in MPEC 2004-R45 of 9 Sept. This object was also observed on 9 and 10 Sept. by LINEAR, on 10 and 12 Sept. by Great Shefford Obs., and on 11 Sept. by KLENOT.
2004 QF14
99 m/yd22.6624.224.2 2004-Q460.017958 AUUseful, visibility ends 8 Oct.
2004 QF14 was observed on 5 Sept. by KLENOT, on 10 Sept. by Farpoint Obs., and on 11 Sept. by LINEAR and Desert Moon Obs.
2004 PF20
108 m/yd22.4822.522.5 2004-P360.110547 AUNecessary, visibility ends 25 Sept.
2004 PF20 was observed on 8 Sept. by Jornada Obs. This more than doubled the observing arc length, taking it from 14.616 to 29.827 days.
2004 RE84
149 m/yd21.7822.222.6 2004-R550.019411 AU
NEW: 2004 RE84 was discovered on 10 Sept. by LINEAR, was confirmed on 10 Sept. by KLENOT, Table Mountain Obs., and Sandlot Obs., and was announced in MPEC 2004-R55 of 11 Sept. This object was also observed on 11 Sept. by LINEAR. It has an MOID of 0.028 AU with Venus.

  Small object observation cross index   [table top]
ObjectObserved by MPC code
2004 PF20715
2004 PG20540
2004 QF14246, 448, 704 & 734
2004 RB11143, 246, 704, 734, 854 & J95
2004 RC11012, 246, 704, 734, 854, H06 & J95
2004 RC80246, 704 & J95
2004 RE84246, 673, 704 & H36
2004 RU109246, 651, 704, G90, H06, H36 & J95
2004 RW2163, 246, 649, 651, 673, 704, 734 & J95
CodeObservatoryObjects observed (days)
012Uccle Obs.2004 RC11
143Gnosca Obs.2004 RB11
163Roeser Obs.2004 RW2
246KLENOT2004 QF14, 2004 RB11(2), 2004 RC11(2), 2004 RC80, 2004 RE84, 2004 RU109 & 2004 RW2
448Desert Moon Obs.2004 QF14
540Linz Obs.2004 PG20
649Powell Obs.2004 RW2
651Grasslands Obs.2004 RU109 & 2004 RW2
673Table Mountain Obs.2004 RE84 & 2004 RW2
704LINEAR2004 QF14, 2004 RB11(3), 2004 RC11, 2004 RC80(3), 2004 RE84(2), 2004 RU109 & 2004 RW2(3)
715Jornada Obs.2004 PF20
734Farpoint Obs.2004 QF14, 2004 RB11, 2004 RC11 & 2004 RW2
854Sabino Canyon Obs.2004 RB11 & 2004 RC11
G90Three Buttes Obs.2004 RU109
H06New Mexico Skies
 – Jim Bedient
 – Robert Hutsebaut
2004 RC11
2004 RU109
H36Sandlot Obs.2004 RE84 & 2004 RU109
J95Great Shefford Obs.2004 RB11(2), 2004 RC11, 2004 RC80, 2004 RU109(2) & 2004 RW2(2)
News briefs – panel 1/1 Major News for 12 Sept. 2004 previous
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News briefs

Amateur NEO discovery:  Announced today in MPEC 2004-R61, 2004 RS109 is the year's fourth NEO discovered from an amateur observatory, found Friday night at Crni Vrh Observatory in Slovenia by Herman Mikuz, who also shares credit for this year's first amateur discovery, 2004 FF29, back in March (see news and image).

PHO recovery:  MPEC 2004-R66 reports the recovery of PHO 2003 KN18 [link|alt] with the Spacewatch 1.8m telescope in Arizona. This half-kilometer object was discovered with Spacewatch's 0.9m telescope in May 2003 and was briefly listed with impact solutions.

Risk monitoring - panel 1/1 Major News for 12 Sept. 2004 previous
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Risk monitoring 12 Sept.

JPL has posted 2004 RU109, which was announced today in MPEC 2004-R63 as discovered yesterday morning by LINEAR in New Mexico. This small object has been added to Sormano Observatory's SAEL list with an Earth flyby tomorrow at 0.002465 AU. That is just under one lunar distance and the sixth-closest known passage so far this year. See above for more about this small object.

The Sunday Daily Orbit Update MPEC (DOU) carries observation of 2004 RF84 from LINEAR yesterday morning and from Great Shefford Observatory in England this morning. Today NEODyS posted this kilometer-size object, and JPL cuts its impact solution count from 166 to 25 while also lowering overall risk ratings.

The DOU also reports observation of 2004 RJ84 yesterday morning by LINEAR and this morning by Great Shefford. Today JPL removed all of its solutions for this object, which it estimated to be on the order of 638 meters/yards wide.

Summary Risk Table - sources checked at 0120 UTC, 13 Sep




 2004 RU109JPL 9/122038-20536-6.33-6.7001.069
 2004 RJ9 NEODyS 9/102049-20491-6.16-6.1603.796
JPL 9/102049-20942-6.06-6.0903.796
 2004 RJ84JPL 9/12R E M O V E D
 2004 RF84 NEODyS 9/122026-208019-4.48-5.0801.906
JPL 9/122034-210025-4.24-4.9401.906
VI = count of "virtual impactors" (impact solutions)
See A/CC's Consolidated Risk Tables for more and maybe
  newer details, and check the monitors' links for latest info.
Note that only objects recently in view are shown here.   [ top ]
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