Monday5 April 200410:10pm MDT2004-04-06 UTC 0410 back top next  


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


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Cover: Two of the fast-moving small objects caught by Peter Birtwhistle at Great Shefford Observatory in England the week before last, 2004 FA5 at right and 2004 FN8, the smallest object observed for two weeks (see below). Stacking several dozen frames on object motion causes stars to appear as strings of beads.

Details: — Left, 2004 FN8. 2004 Mar 25 2302-2326 UT. Mag +19.1. Stacked for motion of 23"/min in p.a. 171°. 66x8s exposure (8m 48s total). — Right, 2004 FA5 2004 Mar 23 0101-0117 UT. Mag +19.1. Stacked for motion of 34"/min in p.a. 18°. 44x6s exposure (4m 24s total). — Both binned 2x2 and enlarged x2, N up. 0.30m f/6.3 Schmidt-Cassegrain + CCD. P Birtwhistle (J95).
Small objects – panel 1/2 Major News for 5 April 2004 back top next  

Small objects
Discovery & follow-up 29 March – 4 April

This past week, as the Moon brightened, six discoveries of small objects were announced. These asteroids have absolute magnitude (brightness) H calculated at greater than 22.0, roughly estimated at 135 meters/yards wide or less. This compares with seven discovery announcements the previous week, and 13 the week before that. Four of this week's were discovered by LINEAR in New Mexico. One, 2004 FH29, was found with the Siding Spring Survey 0.5m Uppsala Schmidt telescope in Australia, which may have been this program's first discovery with that telescope [it was]. And the other, 2004 FC18, was discovered by FMO Project online volunteer Michael C. Begam while reviewing images from the Spacewatch 0.9m telescope in Arizona (see A/CC's report). Another nine small asteroids were tracked, and observations of four more were reported from the previous week. Two of these four, 1998 XN17 and 2002 FT6, were one-night recoveries by Tim Spahr working with the Whipple Observatory 1.2m telescope in Arizona.

Twenty-three observatories (see below) participated in this work, including the USAF Academy Observatory, and several carried much of the load.

For close flybys by small objects last week, the Sormano Observatory SAEL has just one within ten lunar distances (LD), 2004 FG29 at 0.0155 AU (a bit over 6 LD). And this week the only one predicted happens today, 2004 FH29 at 0.020 AU (7.8 LD).

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

If an asteroid's orbit brings it to within 0.05 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 is dimmer, thus smaller. And 0.05 astronomical units (AU) is about 19.5 times the distance between Earth and Moon (0.00256 AU).

Notes: Diameters in the following observation summary table are rough best estimates from a standard but very inexact H-to-size formula using H (absolute magnitude) from the JPL NEO Orbital Elements page, source also for Earth MOID (minimum orbital intersection). Other planetary MOIDs are from Lowell Observatory. Current Minor Planet Center H is also given, along with the original H from each object's discovery MPEC. Priorities and visibilities are from the European Spaceguard Central Node (SCN). NEO orbital elements, H values, and MOIDs are from today, Monday the 5th.

Small objects – panel 2/2 (table) Major News for 5 April 2004 back top next  

Small object observation summary for 29 March–4 April

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 FN8
Apollo
13 m/yd27.0827.126.9 2004-F580.00953 AUUrgent, visibility ends 13 Apr.
2004 FN8 was observed on 29 March by Tenagra II Obs. and Mt. John Obs. It has an MOID of 0.044 AU with Mars. See the cover image above.
2004 FM32
Apollo
16 m/yd26.6027.227.2 2004-G010.00221 AU
NEW: 2004 FM32 was discovered on 30 March by LINEAR, was confirmed on 31 March by LINEAR, and on 1 April by Powell Obs. and Table Mountain Obs., and was announced in MPEC 2004-G01 of 1 April. This object was also observed on 1 April by Tenagra II Obs.
2004 FY15
Apollo
20 m/yd26.1126.126.1 2004-F660.00132 AU
2004 FY15 was reported this last week as observed on 27 March by Mt. John Obs. It has an MOID of 0.035 AU with Mars.
2004 FG29
Aten
24 m/yd25.7826.026.4 2004-F860.00968 AU
NEW: 2004 FG29 was discovered on 29 March by LINEAR, was confirmed on 29 March by Great Shefford Obs., and on 30 March by Powell Obs. and Table Mountain Obs., and was announced in MPEC 2004-F86 of 30 March. This object was also observed on 30 March by LINEAR and Mt. John Obs. and on 31 March by Great Shefford Obs. and Tenagra II Obs.
2004 FB16
Amor
32 m/yd25.1225.725.7 2004-F680.05057 AUUrgent, visibility ends 12 Apr.
2004 FB16 was observed on 29 March by Mt. John Obs.
2004 FM4
Apollo
41 m/yd24.5925.124.1 2004-F460.01084 AUNecessary, visibility ends 10 Apr.
2004 FM4 was observed on 29 and 31 March with the Australian National University (ANU) 1.0m telescope. This object has an MOID of 0.010 AU with Mars.
2004 FC18
Apollo
46 m/yd24.3224.424.5 2004-F780.01981 AU
NEW: 2004 FC18 was discovered on 27 March with the Spacewatch 0.9m telescope by FMOP online volunteer Michael C. Begam (see A/CC report). It was confirmed on 29 March by Desert Moon Obs. and Sabino Canyon Obs., and was announced in MPEC 2004-F78 of 29 March. This object was also observed on 29 March by Tenagra II Obs., the Spacewatch 1.8m telescope, Great Shefford Obs., and KLENOT, on 30 March with the Spacewatch 1.8m telescope, KLENOT, and Great Shefford Obs., and on 1 April by Powell Obs.
2004 FK2
Amor
49 m/yd24.1824.324.6 2004-F380.03680 AUNecessary, visibility ends 18 Apr.
2004 FK2 was observed on 29 March by Great Shefford Obs.
2004 FJ31
Apollo
54 m/yd23.9924.424.4 2004-F950.02212 AU
NEW: 2004 FJ31 was discovered on 29 March by LINEAR, was confirmed on 30 March by LINEAR, and on 31 March by Great Shefford Obs., Powell Obs., Table Mountain Obs., and Sabino Canyon Obs., and was announced in MPEC 2004-F95 of 31 March. It hasn't been reported since.
2004 FH29
Apollo
57 m/yd23.8724.023.7 2004-F870.01527 AU
NEW: 2004 FH29 was discovered on 29 March with the SSS 0.5m telescope, was confirmed on 29 and 30 March with the ANU 1.0m telescope, and on 30 March by Mt. John Obs., and was announced in MPEC 2004-F87 of 30 March. This object was also observed March 30th through April 2nd with the ANU 1.0m telescope, by Mt. John Obs. on March 30th and April 1st, and by Tenagra II Obs. on April 1st.
2004 EU22
Apollo
62 m/yd23.6723.723.7 2004-F220.00800 AUUseful, visibility ends 25 May
2004 EU22 was observed on 17 March by Schiaparelli Obs., on 19 March by the USAF Academy Obs., on 28 March by Camarillo Obs. and Guidestar Obs., on 30 March by LINEAR, Crni Vrh Obs., and Tentlingen Obs., and on 31 March by LINEAR.
2004 FB18
Amor
64 m/yd23.6123.923.5 2004-F760.05852 AUNecessary, visibility ends 23 Jun.
NEW: 2004 FB18 was discovered on 28 March by LINEAR, was confirmed on 28 March by Starkenburg Obs. and KLENOT, and was announced in MPEC 2004-F76 of 29 March. This object was also observed on 28 March by Ondrejov Obs., on 29 March by Wykrota Obs., LINEAR, and KLENOT, on 30 March by Desert Moon Obs., LINEAR, and the ANU 1.0m telescope, on 31 March by LINEAR and Mt. John Obs., and on 1 April by Tenagra II Obs.
2004 FE4
Amor
78 m/yd23.1923.723.5 2004-F450.07566 AUNecessary, visibility ends 24 Apr.
2004 FE4 was observed on 29 and 30 March by Mt. John Obs.
2004 FA
Apollo
82 m/yd23.0723.223.4 2004-F100.01667 AU
2004 FA was reported this last week as observed on 19 March by Hobbs Obs.
2004 FP4
Amor
94 m/yd22.7923.323.3 2004-F470.05302 AUNecessary, visibility ends 19 Jul.
2004 FP4 was observed on 28 March by LINEAR, on 29 March by KLENOT, and on 1 April by Tenagra II Obs. It has an MOID of 0.009 AU with Mars.
1998 XN17
Aten
112 m/yd22.4122.822.7 1998-Y190.05555 AU
Recovery: 1998 XN17 was reported this last week as observed on 24 March by Tim Spahr from Whipple Obs., the first it has been reported since 27 March 2003.
2002 FT6
Aten
120 m/yd22.2522.622.7 2002-F730.04081 AU
Recovery: 2002 FT6 was reported this last week as picked up 24 March by Tim Spahr using the Whipple Obs. 1.2m telescope. It had been last seen on 3 April 2003.
2004 EH1
Apollo
132 m/yd22.0522.322.3 2004-E460.03660 AUUrgent, visibility ends 16 Apr.
2004 EH1 was observed on 28 March by KLENOT, on 29 March by Tenagra II Obs. and the ANU 1.0m telescope, on 30 March by Great Shefford Obs., and on 2 April with the ANU 1.0m telescope.
2004 EK1
Apollo
141 m/yd21.9122.122.1 2004-E480.03506 AUNecessary, visibility ends 13 May
2004 EK1 was observed on 1 April by Tenagra II Obs.

  Small object observation cross index   [table top]
ObjectObserved by MPC code
1998 XN17696
2002 FT6696
2004 EH1246, 413, 926 & J95
2004 EK1926
2004 EU22106, 204, 670, 704, 712, A16 & A17
2004 FA750
2004 FB16474
2004 FB18246, 413, 448, 474, 557, 611, 704, 859 & 926
2004 FC18246, 291, 448, 649, 854, 926 & J95
2004 FE4474
2004 FG29474, 649, 673, 704, 926 & J95
2004 FH29413, 474, 926 & E12
2004 FJ31649, 673, 704, 854 & J95
2004 FK2J95
2004 FM4413
2004 FM32649, 673, 704 & 926
2004 FN8474 & 926
2004 FP4246, 704 & 926
2004 FY15474
CodeObservatoryObjects observed (days)
106Crni Vrh Obs.2004 EU22
204Schiaparelli Obs.2004 EU22
246KLENOT2004 EH1, 2004 FB18, 2004 FC18(2) & 2004 FP4
291Spacewatch 1.8m telescope2004 FC18(2)
413Australian National University 1.0m telescope2004 EH1(2), 2004 FB18, 2004 FH29(6) & 2004 FM4(2)
448Desert Moon Obs.2004 FB18 & 2004 FC18
474Mt. John Obs.2004 FB16, 2004 FB18, 2004 FE4(2), 2004 FG29, 2004 FH29(3), 2004 FN8 & 2004 FY15
557Ondrejov Obs.2004 FB18
611Starkenburg Obs.2004 FB18
649Powell Obs.2004 FC18, 2004 FG29, 2004 FJ31 & 2004 FM32
670Camarillo Obs.2004 EU22
673Table Mountain Obs.2004 FG29, 2004 FJ31 & 2004 FM32
696Whipple Obs.1998 XN17 & 2002 FT6
704LINEAR2004 EU22(2), 2004 FB18(3), 2004 FG29(2), 2004 FJ31(2), 2004 FM32(2) & 2004 FP4
712USAF Academy Obs.2004 EU22
750Hobbs Obs.2004 FA
854Sabino Canyon Obs.2004 FC18 & 2004 FJ31
859Wykrota Obs.2004 FB18
926Tenagra II Obs.2004 EH1, 2004 EK1, 2004 FB18, 2004 FC18, 2004 FG29, 2004 FH29, 2004 FM32, 2004 FN8 & 2004 FP4
A16Tentlingen Obs.2004 EU22
A17Guidestar Obs.2004 EU22
E12Siding Spring Survey (SSS) 0.5m telescope2004 FH29
J95Great Shefford Obs.2004 EH1, 2004 FC18(2), 2004 FG29(2), 2004 FJ31 & 2004 FK2
News briefs – panel 1/1 Major News for 5 April 2004 back top next  
News briefs

Rosetta status:  The Rosetta mission has posted its sixth status report, dated April 3rd, "Ongoing Commissioing Activities," when the spacecraft was about 27.5 lunar distances from Earth. The NASA/JPL Microwave Instrument for the Rosetta Orbiter (MIRO) was activated and practiced a "a very complex pointing profile resulting in a triple-spiral scanning of the planet Venus." JPL has a MIRO site for this far-infrared sub/millimeter instrument, but with outdated info about which comet and asteroids will be visited.

Meteor news:  The Australian Townsville Bulletin reports tomorrow that "James Cook University astronomy centre director Associate Professor Graeme White said eye witness accounts put one impact site about 60 nautical miles north-northeast of Mount Isa" and is "Keen to hear from anyone who may be able to fly by the area." This continues a news thread from April 2nd ("Meteor news").

The Georgia Savannah Morning News has an article today telling about "Bulloch County farmer holding out for big bucks for not-so-big rock," having refused an offer of $25,000 for the meteorite (photo) found while bean picking. See also A/CC's brief report about the meteorite find.

Risk monitoring - panel 1/1 Major News for 5 April 2004 back top next  
Risk monitoring 5 April

The Monday Daily Orbit Update MPEC (DOU) carries no observations of objects with impact solutions. The Sunday DOU had observation of 2004 FE31 from the 2.5m Isaac Newton Telescope at La Palma in the Canary Islands early on the 3rd. Yesterday NEODyS cut its impact solution count and slightly lowered its overall risk ratings for this object, while JPL added many solutions and raised its ratings for 2004 FE31 over a period extending 23 years beyond the NEODyS time horizon.

Summary Risk Table - sources checked at 0014 UTC, 6 Apr

Object

Assessment

Years

VI
PS
cum
PS
max
T
S
Arc 
days
 2004 FU4NEODyS 4/2R E M O V E D
JPL 4/22085-20851-3.07-3.07013.259
 2004 FE31 NEODyS 4/42014-208013-3.13-3.3004.695
JPL 4/42012-210353-2.96-3.1004.695
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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