Thursday22 April 20046:14pm MDT2004-04-23 UTC 0014 back top next  

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


Today's issue status: done
yesterdayApriltomorrowIndex
  • News briefs – FMOP discovery, namings, Mt. Graham controversy, comet news, dark skies & Arecibo upgrade
  • Risk monitoring – JPL has removed 2004 GA1
    panel 2 – JPL has posted 2004 HE12, 2004 HF12 & 2004 HK12

Cover: With stacking in color channels to indicate motion, Bill Yeung shows here the faint Jupiter Trojan asteroid, 2004 HS1, that he discovered at opposition three nights ago and confirmed the following night. The brighter object is coincidentally Main Belter 6743 Liu, which was in the April 8th "cover" image.

Details: 18"+ST10XME CCD, 10 mins. exposure, no filter used. 2004 HS1 motion 0.13 deg/day or 0.325 arcsec/min, PA = 288.49°. 6743 Liu motion 0.28 deg/day or 0.7 arcsec/min, PA = 273.66°.

News briefs – panel 1/1 Major News for 22 April 2004 back top next  
News briefs

FMOP discovery:  An object discovered today by Spacewatch FMO Project online volunteer Richard Broad of Brisbane, Austrailia is currently on the NEO Confirmation Page (NEOCP) as SW40DJ, "moving very fast at 11.5 deg/day and it is also faint."

Namings:  The Arizona Prescott Daily Courier has an article from yesterday, "Prescott is home to top hunter of asteroids." It reports that Paul Comba has discovered 1,150 asteroids, all since his 70th birthday (1996), and says "the Minor Planet Center that catalogs and assigns numbers to asteroids is so far behind on its work that Comba has been able to name only 351 of them."

Mt. Graham controversy:  The University of Minnesota is a partner in the Mt. Graham International Observatory (MGIO) in southeastern Arizona. And the campus newspaper, Minnesota Daily, has eight articles and an editorial in yesterday and today's editions telling about disputes involving the university, astronomers, Apaches, and environmentalists.

Comet news:  The German Comet Section page this morning posted what may be the first post-perihelion image of comet C/2004 F4 (Bradfield), made this morning by Michael Jaeger in Austria at "70 min prior sunrise." Space.com has posted a guide for dawn viewing of C/2004 F4 with the unaided eye 23-25 April.

Dark skies:  Astronomy.com has an article from yesterday, "National Dark Sky Week, April 19-26."

Arecibo upgrade:  A Cornell University news release yesterday tells about new equipment that makes Arecibo "incredibly more sensitive" for radio astronomy by going from single-pixel to seven-pixel measurements, but said nothing about planetary radar. A/CC asked Mike Nolan there about this. He said today that "For asteroids, it doesn't help. The Arecibo diffraction limit at 13cm is 2 arcminutes, so more pixels doesn't buy you anything. One could imagine doing comet work at that resolution, but ALFA is not at a wavelength that's of any interest for minor planets. Its range is 20-25cm, while the radar is at 13 and the observable comet OH line is at 18cm."

Risk monitoring - panel 1/2 Major News for 22 April 2004 back top next  
Risk monitoring 22 April

The Thursday Daily Orbit Update MPEC (DOU) carries observations of 2004 GA1 from discoverer Reedy Creek Observatory in Australia on the 20th, and from Sandlot Observatory in Kansas and Hunters Hill Observatory in Australia yesterday. And today JPL eliminated its last impact solution for this kilometer-size asteroid.

Sandlot also caught 2004 GE2 yesterday morning and today JPL very slightly lowered its risk assessment for the one remaining impact solution for this object.

The DOU has observations of 2004 HD2 from LINEAR in New Mexico yesterday morning and Great Shefford Observatory in England last night. Today JPL slightly raised its low risk ratings for this object.

And the Siding Spring Survey in Australia, discoverer of 2004 HW, reported a set of positions for that kilometer-size object spanning 1.57 hours. Today JPL cuts its impact solution count for 2004 HW from 271 to just nine (five beyond the NEODyS 2080 time horizon), and lowered its overall risk ratings. And

Summary Risk Table - sources checked at 2359 UTC, 22 Apr

Object

Assessment

Years

VI
PS
cum
PS
max
T
S
Arc 
days
 2004 HZ NEODyS 4/212008-207778-4.49-5.0701.039
JPL 4/212008-2101132-4.69-5.1001.039
 2004 HW NEODyS 4/222045-20563-6.16-6.3902.054
JPL 4/222017-21029-3.80-4.1102.054
 2004 HQ1 NEODyS 4/222071-20804-5.97-6.1202.814
JPL 4/222071-210112-4.96-5.1902.814
 2004 HMJPL 4/222101-21042-5.14-5.1405.634
 2004 HK12JPL 4/222008-2103220-3.91-4.3301.168
 2004 HF12JPL 4/222070-20701-6.10-6.1002.018
 2004 HE12JPL 4/222013-2104139-2.82-3.5402.016
 2004 HD2JPL 4/222086-21003-5.22-5.4901.794
 2004 GE2JPL 4/222100-21001-4.98-4.9709.029
 2004 GA1JPL 4/22R E M O V E D
NEODyS 4/19R E M O V E D
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.

NEODyS cuts its solution count from 19 to three and significantly lowered its overall risk ratings for 2004 HW.

more risk monitoring >>

Risk monitoring - panel 2/2 Major News for 22 April 2004 back top next  

<< continued from panel 1

The DOU has observations of 2004 HM from Sandlot yesterday morning and Begues Observatory in Spain last night. JPL's updated assessment very slightly raises its low ratings for this object.

2004 HQ1 is reported from Great Shefford last night. JPL has cut its solution count from 34 to 12 and very slightly lowered its risk ratings for 2004 HQ1 and a later NEODyS update has left its assessment almost unchanged.

The Minor Planet Center Last Observation page is showing that the one object of current concern missing from today's DOU, 2004 HZ, was caught yesterday by KLENOT in the Czech Republic.


Updates: A/CC's 1935 UTC update reported JPL's new risk assessment for 2004 HQ1 and new posting of objects 2004 HE12, HF12, and HK12. A 2024 UTC update reported the new NEODyS assessment for 2004 HQ1 and JPL's new assessment for 2004 HM.

1935 UTC update:  JPL has posted three objects of four newly announced so far today. 2004 HE12 was discovered by Anne Descour early Tuesday with the Spacewatch 1.8m telescope in Arizona (MPEC 2004-H45), while LINEAR discovered 2004 HF12 at about the same time (MPEC 2004-H46) and 2004 HK12 yesterday morning (MPEC 2004-H48).

2004 HF12, which has only one very-low rated impact solution in the year 2070, is estimated by JPL at about 300 meters/yards wide. 2004 HK12, estimated to be somewhat smaller, has 220 solutions, which isn't unusual for a highly preliminary risk assessment based on observations spanning only 28 hours. And 2004 HE12 comes in at 650 meters wide, or about 0.4 mile, a number that comes from an inexact but standard formula for converting an object's brightness to diameter.

Confirming were Table Mountain Observatory and the Spacewatch 0.9 telescope for 2004 HE12, Table Mountain, Great Shefford, and Sabino Canyon Observatory for 2004 HF12, and KLENOT and Hunters Hill for 2004 HK12.

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