Sunday11 July 20043:26pm MDT2004-07-11 UTC 2126 back top next  

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

Today's issue status: done

FridayJulyTuesdayIndex

Cover: An animation of small object 2004 MC from Peter Birtwhistle created from observations he and Juan Lacruz performed at Great Shefford Observatory in England on the night of June 16th, an occasion recorded here. Motion is toward the lower left.

Details: 2004 MC. 2004 June 16 2229-2245 UT. Mag. +19.1. Two sets of 10x30s exposures, total exposure 5 mins. each. Binned 2x2. Motion 1.3"/min. in p.a. 159°. Field 22'x25', north up. 03.m f/6.3 Schmidt-Cassegrain + CCD, P. Birtwhistle & J. Lacruz (J95).
Small objects – panel 1/2 Major News for 11 July 2004 back top next  

Small objects   Follow-up for 5-11 July

The Minor Planet Center reports that, due to computer problems overnight, “the DOU MPEC preparation routine did not even begin running. This morning's DOU MPEC is therefore abandoned.” And so A/CC's small objects report is brief due to having six instead of seven days' data, and having little data from the six Daily Orbit Update MPECs.

Four small near-Earth asteroids (defined at right) were tracked by nine observatories this past week. No NEOs of any size were announced as discovered, and the NEO Confirmation Page was all but empty. This lull can be attributed to short nights in the northern hemisphere, some bad weather, smoke in the southwestern U.S., and maybe some survey down time. Arizona wildfire fighting is being helped by the onset of “monsoon season,” but that itself will now interfere on and off with the most productive NEO discovery activities for the next several weeks.

2004 MO4 flew by Earth at 10.4 lunar distances (LD) last Thursday, 2004 LK was at 29.9 LD Wednesday, and 2003 YN107 was at 23.3 LD yesterday. No small NEA close flybys are predicted for next week.

<< 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 11 July 2004 back top next  

Small object observation summary for 5-11 July

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 MO4
Amor
32 m/yd25.1524.924.6 2004-M450.02326 AUNecessary, visibility ends 3 Aug.
A break of more than five days ended when 2004 MO4 was observed on 4 and 5 July by Great Shefford Obs., on 5 and 7 July by CINEOS (its discoverer), on 6 July by Desert Moon Obs., on 7 July by Sandlot Obs., and on 8 July by Reedy Creek Obs. It has an MOID of 0.027 AU with Mars, and flew past Earth at 10.4 lunar distances (LD) on July 8th.
2004 LK
Amor
99 m/yd22.6822.722.7 2004-L220.06874 AUUseful, visibility ends 10 Oct.
2004 LK was observed on 9 July by Mt. John Obs., adding 21.99 days to what had been a 7.91-day observing arc. This object flew past Earth at 29.9 LD on 7 July.
2004 MO3
Apollo
119 m/yd22.2722.422.3 2004-M390.01127 AUUseful, visibility ends 19 Aug.
2004 MO3 was observed on 4 July by Eschenberg Obs. and on 7 July by Table Mountain Obs. It has an MOID of 0.024 AU with Mars.
2004 MS1
Apollo
121 m/yd22.2422.322.1 2004-M290.00606 AUNecessary, visibility ends 12 Aug.
2004 MS1 was observed July 9th by Francisquito Obs., adding 9.24 days to an observing arc that had been 11.64 days long.

  Small object observation cross index   [table top]
ObjectObserved by MPC code
2004 LK474
2004 MO3151 & 673
2004 MO4428, 448, 599, H36 & J95
2004 MS1G70
CodeObservatoryObjects observed (days)
151Eschenberg Obs., Switzerland2004 MO3
428Reedy Creek Obs., Queensland, Australia2004 MO4
448Desert Moon Obs., New Mexico2004 MO4
474Mt. John Obs., New Zealand2004 LK
599CINEOS, Italy2004 MO4(2)
673Table Mountain Obs., southern California2004 MO3
G70Francisquito Obs., southern California2004 MS1
H36Sandlot Obs., Kansas2004 MO4
J95Great Shefford Obs., England2004 MO4(2)
News briefs – panel 1/1 Major News for 11 July 2004 back top next  
News briefs

Occultation news:  David Dunham has updated his pages here and here on the 2-3 July meeting of the International Occultation Timing Association (IOTA) in southern California to include links to some of the presentations (mostly large PowerPoint files) and results from stellar occultations by Main Belt asteroids observable nearby June 30th to July 6th. Successfully observed were occultations by 64 Angelina, 522 Helga, and 559 Nanon, while 524 Fidelio was missed and 491 Carina was seen by just one observer due to “the largest prediction error relative to the claimed accuracy in recent memory.”

For the July 6th morning occultation by 491 Carina, Dunham reports “the largest deployment for an asteroidal occultation by one observer.” He put “4 telescopes and cameras at about 5-mile intervals for 16 miles.” However, one telescope was clamped wrong, another was removed by a farm worker (recovered later), and then the prediction for the ground path proved to be wrong.

Bits & pieces:  The July edition of Distant EKOs is now available. It gives abstracts and links to two papers on size distribution of Edgeworth Kuiper Belt objects (EKBOs), and has abstracts on EKBO/Centaur spectral studies and the observation of several particular objects, including detection of water ice on large EKBO 2004 DW. An abstract about Spitzer observations of 29P/Schwassmann-Wachmann 1 tentatively reports “a rotation period in excess of 60 days” and detection of olivine. There is also information about planetary disks around other stars such as tau Ceti, the mathematics behind EKBO binary formation, and three doctoral/masters dissertations.

An Associated Press wire story yesterday reported that the fight against wildfires close to telescopes on Mt. Graham continued to be aided by weather. AP tells today of more precipation, however “lightning started a new blaze Saturday in the steep terrain on the mountain's south side,” and the two original fires, the Gibson and the Nutall, today merged into one.

Risk monitoring - panel 1/1 Major News for 11 July 2004 back top next  
Risk monitoring Friday 11 July Tuesday

At last check today Sunday, there has been no news to report in risk monitoring since Thursday.

Summary Risk Table - sources checked at 1926 UTC, 11 Jul

Object

Assessment

Years

VI
PS
cum
PS
max
T
S
Arc 
days
 2004 MP7JPL 7/82087-20871-3.94-3.94011.343
NEODyS 7/1R E M O V E D
 2004 MO7 NEODyS 6/302012-208067-4.34-5.2003.869
JPL 6/302016-208811-4.83-5.4803.869
 2004 ME6JPL 6/282017-209943-5.64-6.3500.873
 NEODyS 6/272044-20637-7.29-7.7600.873
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.
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