Sunday4 July 20048:19pm MDT2004-07-05 UTC 0219 back top next  

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

Today's issue status: done


Cover: Small object 2004 LA10 caught early on June 28th by Peter Birtwhistle at Great Shefford Observatory in England, seen in a stack of 45 14-second exposures made over a 27-minute period, with a gap to avoid interference from a bright star. See below for a more difficult capture. 2004 LA10 was one of the few small asteroids followed this past week, and was the subject of the June 20th cover about discovery confirmation.

Details: 2004 LA10. 2004 June 28 0141-0208 UT. Mag +19.4. 45x14 second exposures (total exposure 10m30s). Binned 2x2 and enlarged x2. Motion 14"/min in p.a. 88°. Field 10'x10', North up, 0.30m f/6.3 Schmidt-Cassegrain+CCD.
Interlaced stacking – panel 1/1 Major News for 4 July 2004 back top next  
The red line shows 2004 LA10's movement 24 June 2004 in the exposures used in the animation. Frame 1 000420-002115 UT. Frame 2 000455-002140 UT. Both frames 12x10s, total exposure 2 mins each. Binned 2x2 and enlarged x2. Ephemeris Mag +19.1, Motion 17"/min in p.a. 86°. Field 5'x5', north up, 0.3m f/6.3 Schmidt-Cassegrain+CCD.
Blink pair from interlaced stacking 
for 2004 LA10 by Peter Birtwhistle 
at Great Shefford Obs.

Interlaced stacking
By Peter Birtwhistle

2004 LA10 was moving through a very dense part of the Milky Way in central Aquila, 1/2° NE of star cluster NGC 6760 on June 24.0 UT, and 45 ten-second exposures were taken to try and detect this 19th-magnitude object moving at 17"/min. Twenty-one of the images were unusable, as the object passed close to field stars.

Finding such a faint object in a rich starfield can be very difficult, and, to help identification, the 24 images were stacked, not in two consecutive sets (1-12 and 13-24), but in ‘interlaced’ sets (1,3,5,... and 2,4,6,...). This has the effect of putting the object very close to the same position on both stacks, in this case with just 28 seconds of time between the two, helping the eye to be able to pick out the moving object.

Small objects – panel 1/2 Major News for 4 July 2004 back top next  

Small objects
Discovery & follow-up for 28 June–4 July

With the full Moon and short nights in the northern hemisphere, seven observatories (six northern and one Australian) still managed to track five small asteroids this past week, although not 2004 ME6, the only one with impact solutions (“small” is defined at right).

Since last Monday, only eight minor object discoveries have been announced. Six were distant, and discovered back in February-March. Another, an NEO announced June 29th but not seen since June 20th, was found to have impact solutions, as did the the remaining discovery, a smallish asteroid (H=21.7) announced June 29th (see June 30th). No H>22.0 asteroids were announced.

For close approaches by small asteroids, the Minor Planet Center has 2004 MC as having been at 3.66 lunar distances (LD) of Earth at 2004 June 29.51. JPL is showing that 2004 LK, which hasn't been reported since June 17th, will be at 29.9 LD on July 7th, 2004 MO4 will be at 10.4 LD on July 8th, and co-orbital candidate 2003 YN107 will be at 23.3 LD on July 10th.

<< 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 samplings of distant asteroid populations, 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 except as noted. See also the Sormano Observatory SAEL list of asteroids with H>22.0 and Earth MOID<0.015 AU.
Small objects – panel 2/2 (table) Major News for 4 July 2004 back top next  

Small object observation summary for 28 June–4 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.

European Spaceguard Central Node
2004 LA10
34 m/yd24.9725.124.7 2004-L660.02988 AUNecessary, visibility ends 13 July
2004 LA10 was observed on 28 June by Great Shefford Obs. (see "cover" above). It has an MOID of 0.009 AU with Mars.
2004 MO4
35 m/yd24.9224.624.6 2004-M450.02326 AUUrgent, visibility ends 3 Aug.
2004 MO4 was observed on 29 June by Powell Obs., and was reported this past week as having been observed on 25 June by CINEOS and by Tim Spahr at Whipple Obs. Also this past week, the CINEOS 2004 MO4 discovery observations of 22 June were restated with new times. This object has an MOID of 0.027 AU with Mars, and will will be at 10.4 lunar distances (LD) on July 8th.
2004 LB1
78 m/yd23.1823.223.1 2004-L300.03331 AUUrgent, visibility ends 9 July
2004 LB1 was reported this past week as observed on 19 June by Wykrota Obs.
2004 MC
79 m/yd23.1623.323.3 2004-M070.00749 AUNecessary, visibility ends 27 July
2004 MC was observed on 20 June by Wykrota Obs., on 26-30 June by Reedy Creek Obs., and on 27 June by Camarillo Obs. This object has an MOID of 0.031 AU with Mars and, although not listed in the JPL Close Approach tables, the Minor Planet Center Closest Approaches page says it was at 3.7 LD at 2004 June 29.51.
2004 MO3
119 m/yd22.2722.422.3 2004-M390.01128 AUUseful, visibility ends 19 Aug.
2004 MO3 was observed on 27 June by Camarillo Obs., on 28 June by Great Shefford Obs., on 2 July by Desert Moon Obs., and on 3 July by La Canada Obs. It has an MOID of 0.024 AU with Mars.
2004 MS1
121 m/yd22.2322.222.1 2004-M290.00605 AUUseful, visibility ends 12 Aug.
2004 MS1 was observed overnight 29-30 June by Modra Obs.

  Small object observation cross index   [table top]
ObjectObserved by MPC code
2004 LA10J95
2004 LB1859
2004 MC428, 670 & 859
2004 MO3448, 670, J87 & J95
2004 MO4599, 649 & 696
2004 MS1118
CodeObservatoryObjects observed (days)
118Modra Obs.2004 MS1
428Reedy Creek Obs.2004 MC(5)
448Desert Moon Obs.2004 MO3
599CINEOS2004 MO4
649Powell Obs.2004 MO4
670Camarillo Obs.2004 MC & 2004 MO3
696Tim Spahr at Whipple Obs.2004 MO4
859Wykrota Obs.2004 LB1 & 2004 MC
J87La Canada Obs.2004 MO3
J95Great Shefford Obs.2004 LA10 & 2004 MO3
News briefs – panel 1/1 Major News for 4 July 2004 back top next  
News briefs

Distant object news:  MPEC 2004-N19 yesterday reported that Reiner Stoss (Index) had located the large distant object 2003 UR292 in the NEAT/Palomar archives from 6, 11, and 17 October 2001 and 5-6 October 2002. In a copyrighted note, Brian Marsden comments that resulting orbital computations “indicate the strong likelihood of close encounters with Neptune, well inside its sphere of influence, within a few millennia of the present time.”

Meteor news:  Sandia National Labs has posted movies of bright meteors caught over Albuquerque, New Mexico with its all-sky camera yesterday morning at 4:04 and 5:18 MDT (414Kb and 494Kb).

A UPI story at the Washington Times dated July 2nd reports that the New Zealand couple whose house was hit by a meteor last month (news thread) have refused “an American bidding $24,000 NZ (USD15,000) and a Korean $50,000 NZ (USD32,000).”

Bits & pieces:  IAUC 8351 of May 31st has been made public with analysis of comet C/2001 Q4 (NEAT) rotation, coming up with 23.2 +/- 0.25 hours, and, from around the time of perihelion, also describes Q4's dust shells (see the May 28th “cover” for an animation of the shells).

If our own Solar System doesn't have enough minor objects for you, then check out the tau Ceti system, which Astrobiology Magazine reported July 2nd has far too many. With “ten times as much material in the form of asteroids and comets as our own solar system [any planets there] would not support life as we know it due to the inevitable large number of devastating collisions.” This conclusion comes from work done with the far infrared (submillimeter) 15m James Clerk Maxwell Telescope (JCMT).

Tau Ceti, only 12 light years away, is the nearest sun-like star [and] is the first star to be found to have a disk of dust and comets around it similar in size and shape to the disk of comets and asteroids that orbits the Sun. ”

Update: The news release that this report came from was posted July 6th by the U.K. Particle Physics and Astronomy Research Council (PPARC).

Risk monitoring - panel 1/1 Major News for 4 July 2004 back top next  
Risk monitoring Thursday 4 July

The Friday, July 2nd, Daily Orbit Update MPEC (DOU) had observation of 2004 MP7 Wednesday morning from discoverer Goodricke-Pigott Observatory in Arizona, and Thursday morning from New Mexico Skies. And Friday JPL slightly raised its low risk assessment for this object.

2004 MP7 was the only object that has impact solutions and is currently in view that was reported in Friday's DOU, and none were reported in the Saturday and Sunday DOUs.

Summary Risk Table - sources checked at 0014 UTC, 5 Jul




 2004 MP7JPL 7/22087-20871-4.12-4.1205.082
 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.   [ top ]
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