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June
2005
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18 June 2005 - Saturday
Risk monitoring: JPL has posted 2005 MC with impact solutions. The discovery of this mile-size object was announced in MPEC 2005-M17 today. Eric Christensen found it Thursday morning while at the Catalina Sky Survey (CSS) 0.68m telescope and followed it up yesterday and this morning with the Mt. Lemmon Survey (MLS) 1.5m telescope, both in the mountains north of Tucson, Arizona. Also confirming the discovery were Robert Hutsebaut in Belgium remotely operating a Rent-A-Scope 0.25m telescope at New Mexico Skies yesterday morning and Gary Hug with the Farpoint Observatory 0.7m telescope in Kansas this morning.
Today's Daily Orbit Update MPEC reports MLS observation of 2004 MN4 yesterday morning, and today NEODyS very slightly changed its risk assessment.
June
2005
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17 June 2005 - Friday
Comet & meteor news: A/CC was alerted today to a June 14th news release about how comets that have fragmented into Earth-crossing meteoroid streams and asteroidal-looking remnants may be responsible for most meteor showers. Peter Jenniskens and Esko Lyytinen report that there are now two good examples: potentially hazardous object 2003 WY25, which has been associated with comet D/1819 W1 (Blanpain) and a spectacular 1956 Phoenicid meteor shower, and unusual object 2003 EH1, which is associated with C/1490 Y1 and the Quadrantid shower (see news and image). Other showers may include the Geminids and Daytime Arietids/delta-Aquariids. They comment that it "may not be unnatural" if NASA's Deep Impact mission breaks comet 9P/Tempel 1 "into fragments, creating a cloud of meteoroids" on July 4th. See a link at the bottom of the news release for a PDF preprint of the article to be published in the Astronomical Journal.
There is also an alert from the IAU's Pro-Amat Working Group, which Jenniskens chairs, advising of possible meteors resulting from C/2005 JQ5 (Catalina), not from passages in recent years (last century), but from passages in the period 1300-1500 AD, according to a study by Lyytinen and Jenniskens.
“ For the period June 14 - June 24, a low level of activity may radiate from (for June 17.0) RA = 244.3, Decl. = -9.9 (J2000.0) with Vinf = 19.05 km/s (or Vg = 15.44 km/s). This is near the star psi-Scorpii, just above the ecliptic plane and near the antihelion source direction. To discriminate from sporadic meteors, orbits may need to be determined. A test [of] particles from the 1302 trail near Earth orbit at the current Epoch was found to have orbital elements a = 2.76 AU, q = 0.8417 AU, Node = 86.067 degrees (J2000.0), w = 233.79 degrees, i = 4.94 degrees. ”
They caution that, "It is not known if this comet was active that long ago, nor how much dust it may have ejected." And they predict that, "When the comet is near Earth in 2085, the dust ejected in the return of 2005 will also be close to Earth path that year and the shower may be more prominent." (A/CC has recent news about this comet located temporarily here as, until recently, it had a 2085 impact solution.)
In regard to the most recent comet fragmentation, news of which A/CC reported below, MPEC 2005-M11 today carries the first astrometry of C/2005 K2 (LINEAR) as two separate objects, C/2005 K2-A and C/2005 K2-B.
Also today, MPEC 2005-M12 announces the redesignation of a Centaur-classified object as C/2004 PY42 (CINEOS), which was caught acting cometary at a very distant 12.4 AU from the Sun. Given as observors are Steve Tegler and Bill Romanishin at the 1.8m Vatican Advanced Technology Telescope (VATT) on 7 and 8 June, and Anne Descour this morning at the Spacewatch 1.8m telescope, which had been last to observe it on September 13th. The present MPC orbit calculation has C/2004 PY42 coming away from perihelion at 11.788 AU, between Saturn and Uranus, on April 24th of 2001, and heading toward aphelion at 20.472 AU, out beyond Uranus. This object was discovered by CINEOS (Campo Imperatore Near Earth Objects Survey) in Italy last August 10th, as A/CC noted at the time (see "Unusual object"), and was soon found by Reiner Stoss in NEAT's archives from June and August 2002 (see news).
Risk monitoring: Yesterday's Daily Orbit Update (DOU) carried no observations of objects with impact solutions. Today's DOU reports observation of 2004 MN4 from Pla D'Arguines Observatory in Spain last night, and NEODyS has very slightly changed its risk assessment.
June
2005
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15 June 2005 - Wednesday
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Comet news: Another comet has split, and Ernesto Guido informs A/CC that he and Giovanni Sostero in Italy sent the following discovery message to the CBAT (Central Bureau for Astronomical Telegrams) about C/2005 K2 (LINEAR):
“ G. Sostero and E. Guido (CARA collaboration, http://cara.uai.it) report the detection of a secondary condensation within the coma of C/2005 K2 (LINEAR). The images, obtained in remote mode through a 0.25m f/3.4 reflector + CCD from the "New Mexico Skies" Observatory, reveals the component at the following offsets from the main nucleus 2005 Jun. 13.1560, delta A.R. = -1.91s, delta Decl.= -22.2" (R almost 17.1); Jun.14.1525, -2.74s, -29.8" (R almost 16.9). ”
This work was done remotely with Rent-A-Scope at New Mexico Skies. At right is the June 14th discovery imagery (click to see full size), and you can see the June 13th imagery from Sostero and Guido's C/2005 K2 page, where there are more images and info. Other observers are also credited with reporting the development, as detailed in a CBAT document not available to the public.
MPEC 2005-L65 yesterday announced the discovery of P/2005 L4 (Christensen), one more distant comet found by the Catalina Sky Survey team, this time by Eric Christensen at the Mt. Lemmon Survey telescope in Arizona. It shows his earliest observations on the morning of June 13th but also reports observations on 3, 8, and 12 June from the Spacewatch 0.9m telescope in Arizona. The first preliminary calculation has perihelion this coming August 24th at 2.36550 AU, out past Mars.
Risk monitoring: Late in the day (still afternoon in Pasadena), JPL today very slightly raised its risk assessment for 2004 MN4 based on some of the observations reported in Daily Orbit Update (DOU) MPECs during the last two weeks. Today's DOU, and DOUs for the last two days, carried no observations of objects with impact solutions.