Tuesday24 August 20048:22pm MDT2004-08-25 UTC 0222 last
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The Asteroid/Comet Connection's
daily news journal about
asteroids, comets, and meteors

Today's issue status: done

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Cover: This frame from an animation (919Kb GIF from ORSA@work) by Pasquale Tricarico using the Linux version of ORSA shows the view from 2004 FU162 at its closest approach to Earth — 2.02 Earth radii (ER=6378.137 km.) at 1535 TDT (10:35am EDT) on March 31st. This tiny object flew inside the equatorial geostationary satellite ring (5.6 ER) and through the GPS constellation (3.17 ER), but well above the altitudes at which low Earth orbit and polar orbit satellites travel. And where was the Moon in relation to the object? “Almost exactly one lunar distance” away at closest, he says

Small objects – panel 1/2 Major News for 24 August 2004 back top next  

Small objects
Discovery & follow-up for 16-22 August

During the week of 16-22 August the count of known small asteroids (defined at right) that are actively listed by the Minor Planet Center and/or JPL went past 600, a milestone on the way to discovering many thousands.

Two were discovered during the week, one each by the Catalina Sky Survey (CSS) in Arizona and the associated Siding Spring Survey (SSS) in New South Wales, Australia, and a third was announced from LINEAR in New Mexico back at the end March. Four other small asteroids were tracked, and one was reported from late June. Ten observatories participated in the week's work

There was one fairly close Earth flyby during the week, with 2004 PR92 at 11.8 lunar distances (LD) on Friday. Two objects discovered that day by Spacewatch FMO Project online volunteers and announced on Monday (after the period, see news) come close this week — 2004 QR4 at 6.2 LD on Monday and 2004 QO5 at 13.3 LD on Friday. But these don't sound so close after hearing Sunday's news of 2004 FU162's passage at 0.033 LD in March.

<< 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, visibilities, and campaigns are from the European Spaceguard Central Node (SCN). And flyby distances and times are from the JPL Close Approach Table. All data from 24 Aug. 2004. 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 24 August 2004 back top next  

Small object observation summary for 16-22 August

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.


Object
Estimated
diameter
JPL
H
MPC
H
Discovery
H in MPEC
Earth
MOID
European Spaceguard Central Node
priority/visibility/campaign
2004 FU162
Aten
has VIs
6 m/yd28.6828.728.7 2004-Q220.000072 AU
NEW: 2004 FU162 was discovered on 31 March by LINEAR in observations spanning only 44 minutes and was not otherwise confirmed. Nevertheless, it was announced in MPEC 2004-Q22 of 22 Aug. as told about in A/CC news of 22 and 23 Aug. It has an MOID of 0.021 AU with Venus and on March 31st came within two Earth radii of Earth, the closest asteroid passage ever observed by telescope.
2004 PR92
Apollo
34 m/yd25.0025.125.2 2004-P510.025967 AUUrgent, visibility ends 25 Aug.
2004 PR92 was observed on 13 Aug. by Sormano Obs., on 15 and 18 Aug. by KLENOT, on 16 and 18 Aug. by Powell Obs., on 18 Aug. by Sandlot Obs., and on 18 and 19 Aug. by Great Shefford Obs.. This object passed Earth at 11.8 lunar distances on 20 Aug.
2004 PG20
Amor
42 m/yd24.5324.524.6 2004-P370.047827 AUNecessary, visibility ends 19 Sept.
2004 PG20 was observed on 16 and 19 Aug. by KLENOT and on 18 Aug. by Powell Obs.
2004 QB3
Aten
43 m/yd24.4624.424.4 2004-Q260.020237 AUUrgent, visibility ends 5 Sept.
NEW: 2004 QB3 was discovered on 21 Aug. by the Catalina Sky Survey (CSS), was confirmed on 22 Aug. by Table Mountain Obs. and Grasslands Obs., and was announced in MPEC 2004-Q26 of 22 Aug. It has an MOID of 0.037 AU with Venus.
2004 PJ
Amor
96 m/yd22.7323.123.0 2004-P210.060154 AUUseful, visibility ends 19 Sept.
2004 PJ was observed on 15 and 18 Aug. by KLENOT. It has an MOID of 0.042 AU with Mars.
2004 PF20
Amor
108 m/yd22.4822.622.5 2004-P360.110665 AUUseful, visibility ends 25 Sept.
2004 PF20 was observed on 15 and 18 Aug. by KLENOT and on 18 Aug. by Powell Obs.
2004 QA2
Amor
118 m/yd22.2922.322.1 2004-Q210.029314 AUUrgent, visibility ends 6 Oct. / campaign
NEW: 2004 QA2 was discovered on 20 Aug. by the Southern Sky Survey (SSS), was confirmed on 21 Aug. by Reedy Creek Obs., and was announced in MPEC 2004-Q21 of 21 Aug. It was listed on 22 Aug. by JPL with impact solutions that were removed on the 24th when the next observations became available (after the period of this report, see below).
2004 MO3
Apollo
124 m/yd22.1822.322.3 2004-M390.011269 AU
2004 MO3 was reported this past week as observed on 27 and 28 June by Parma Obs., within the existing observation arc. It has an MOID of 0.024 AU with Mars.

  Small object observation cross index   [table top]
ObjectObserved by MPC code
2004 FU162704
2004 MO3A56
2004 PF20246 & 649
2004 PG20246 & 649
2004 PJ246
2004 PR92246, 587, 649, H36 & J95
2004 QA2428 & E12
2004 QB3651, 673 & 703
CodeObservatoryObjects observed (days)
246KLENOT2004 PF20(2), 2004 PG20(2), 2004 PJ(2) & 2004 PR92(2)
428Reedy Creek Obs.2004 QA2
587Sormano Obs.2004 PR92
649Powell Obs.2004 PF20, 2004 PG20 & 2004 PR92(2)
651Grasslands Obs.2004 QB3
673Table Mountain Obs.2004 QB3
703Catalina Sky Survey (CSS)2004 QB3
704LINEAR2004 FU162
A56Parma Obs.2004 MO3(2)
E12Southern Sky Survey (SSS)2004 QA2
H36Sandlot Obs.2004 PR92
J95Great Shefford Obs.2004 PR92(2)
News briefs – panel 1/1 Major News for 24 August 2004 previous
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News briefs

2004 FU162 update:  Some news sites are carrying a brief Asian News International wire story that mistakenly states 2004 FU162 “was reportedly seen by astronomers last week.” It was observed March 31st. For more about 2004 FU162, see news yesterday and Sunday, links above for an animation by Pasquale Tricarico of 2004 FU162's flight through the Earth's artificial satellite system as seen from FU162, and a risk assessment update below.

Meteor news:  The University of Arizona has a news release today telling that “meteorites, particularly iron meteorites, may have been critical to the evolution of life on Earth [as they] could have provided more phosphorus than naturally occurs on Earth — enough phosphorus to give rise to biomolecules which eventually assembled into living, replicating organisms” And so life “requires an asteroid belt where planetesimals can grow to a critical size — around 500 kilometers in diameter — and a mechanism to disrupt these bodies and deliver them to the inner solar system.” The item is accompanied by a painting by Jim Scotti of the Earth-Moon system a year after formation.

Bits & pieces:  We asked Pasquale Tricarico about the orbital stability of recently discovered 2004 PY42 (see news thread, “Unusual object”). He says:  “The minimum orbit intersection distance (MOID) with Uranus is 1.66 AU, while the MOID with Saturn is 1.77 AU. Jupiter and Neptune are probably too far away for big perturbations, and the object seems (from a quick check of the next 400 years) to be pretty stable, with a near-MOID close encounter with Uranus around June 2039, and a close encounter with Saturn in late 2196, at about 2.7 AU.”

Sky & Telescope has an article today about the early stellar flyby theory for explaining the odd orbit of 2003 VB12 (aka "Sedna"), and concludes: “Either star-encounter scenario implies that many more such objects await discovery.” See news (“Stellar influences”) for more info and links.

The Colorado Denver Post has an August 22nd editorial, “Hubble plan lacks details,” that follows up on the recent media-celebrated “let's go save Hubble” pronouncement from the NASA Administrator. “[When] we put the plan under a microscope, we discovered it was, well, microscopic.”

Risk monitoring - panel 1/1 Major News for 24 August 2004 previous
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Risk monitoring 24 August

JPL has posted 2004 QJ7, which was announced today in MPEC 2004-Q39 as discovered and followed for 3.61 hours yesterday by the Siding Spring Survey (SSS), and confirmed today with the Australian National University 1m telescope at Siding Spring Observatory.

The Tuesday Daily Orbit Update MPEC (DOU) has observations of 2004 QA2 from Saturday morning from Grasslands Observatory in Arizona, and today JPL removed its few impact solutions for this small object.

The DOU has observations of 2004 QZ2 from KLENOT in the Czech Republic very early this morning. Today NEODyS cut from 20 impact solutions beginning in 2011 to just two lower-rated solutions in 2056 and 2068, while JPL cut from 63 to one, in the year 2091. This demonstrates how much and how quickly preliminary risk assessments can change with just a little additional observation.

JPL today very slightly revised its 2004 FU162 risk assessment without new observations. The solution count grew, but having so many impact solutions is not unusual when there is so little observing data. If this tiny object ever enters Earth's atmosphere, it will destruct harmlessly at high altitude while putting on a big show (links to more info above).

Summary Risk Table - sources checked at 0220 UTC, 25 Aug

Object

Assessment

Years

VI
PS
cum
PS
max
T
S
Arc 
days
 2004 QZ2 NEODyS 8/242056-20682-5.60-5.6603.601
JPL 8/242091-20911-4.82-4.8203.601
 2004 QY2 NEODyS 8/232008-207776-1.71-2.6002.042
JPL 8/232007-209981-1.77-2.2202.042
 2004 QJ7JPL 8/242009-2103107-3.23-3.9500.965
 2004 QA2JPL 8/24R E M O V E D
 2004 PU42JPL 8/172071-210318-5.23-5.8503.772
 NEODyS 8/152071-20776-6.23-6.5203.772
 2004 PP97 NEODyS 8/172029-20757-4.04-4.5500.987
JPL 8/172023-210335-3.51-4.1100.987
 2004 FU162JPL 8/242006-2104824-5.38-6.3700.031
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.

The European Spaceguard Central Node today posted observing campaigns for the terrible two's — 2004 QA2, 2004 QY2, and 2004 QZ2, and also for 2004 PP97, which “surprisingly has not been observed in the past week!” and “is very likely to be lost” if not caught immediately.

NEODyS Pisa was put back online overnight. See news last week about computer problems there.

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