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The Asteroid/Comet Connection's news journal about asteroids, comets & meteors   –   21 Sept. 2005

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21
Sept.
2005

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21 September 2005 - Wednesday

Editor's note, Oct. 8th:  I didn't realize it at the time, but September 21st's reporting would be the last regular A/CC narrative news edition. This reporting began three and a half years ago, in March 2002 and was daily until late last year. News editions have grown less frequent and less complete this year as my available time has shrunk to now nearly zero. Thanks again to everyone who has supported this news activity.
      If observers and others continue to find the CRT pages to be of real use, this semi-automated reporting of risk monitoring activities should be able to continue indefinitely. Some changes and enhancements should also make it more useful in the absence of an accompanying news narration.

Call for observation:  This isn't quite within A/CC's usual topic range, although Hyperion may be a captured minor object. Travis Fisher forwards the following message posted to a discussion group at UnmannedSpaceflight.com by Emily Lakdawalla, science and technology coordinator for the Planetary Society, concerning Cassini's September 26th flyby:

I was talking with Amanda Hendrix at JPL today about the upcoming icy satellite encounters, and she asked me if I had any way of getting in touch with amateur observers. They are looking for people to do photometric observations of Hyperion for several days on either side of the flyby. She said "Ground-based observing will help to constrain the current state of rotation of Hyperion, whose spin axis changes. The visual magnitude of Hyperion is 16.5, so serious photometry would require at least a 24-inch telescope."
      Gulp. That's a big telescope, and short notice, with the encounter only 6 days away. I'm not an observer so I don't know how to get in touch with lots of amateurs with big scopes except for the couple of people I know personally.

Cassini's Hyperion page says, "Its eccentric orbit makes it subject to gravitational forces from Saturn, which causes its rotational period to vary from one orbit to the next." See also JPL's July 11th news release about the previous Hyperion flyby.

Controversy:  The September 13th New York Times had an article, posted at CNET's News.com: "One find, two astronomers: An ethical brawl," about controversy over the discovery of 2003 EL61 (see A/CC's July 29th news brief about the discovery). Readers may remember a stunt somewhat similar to what is alleged to have happened, only done in good fun at A/CC's instigation, back when Mike Brown and Chad Trujillo's 90377 Sedna (2003 VB12) discovery was announced in March 2004.
      The discussion of this issue on the mailing lists has been characterized to A/CC by one neutral observer as "extremely heated with an increasing tendency to declare Ortiz et al. as guilty, especially after the IP evidence popped up. Supporters of both sides have been presenting extreme black-and-white views, and little consideration has been given to alternative scenarios to explain the facts, especially by those who voted for 'guilty,' while a lot of consideration was given to negative speculation. It was just like the villagers in Monthy Python's 'Holy Grail' crying 'A witch, we've got a witch!'"
      Last Thursday evening, Jaime Nomen forwarded a message from Jose Luis Ortiz to the Minor Planet Mailing list (MPML). Released to MPML subscribers on Saturday, it said that, "The detailed timeline of our find was given to Daniel Green, director of CBAT long before any controversy." He then repeated the timeline, noting the crucial point of how the discoverers happened upon Mike Brown's pointing information by doing an ordinary Google search on the publicly announced "K40506A" temporary designation.
      Ortiz says in his message that he will post the details to his Web page "in the next few days," and A/CC will provide that link when it becomes available.

Special FMO   by Marco Langbroek
The author reported about FMOP discovery 2005 QQ87 on September 4th. Since then observations were reported in the Daily Orbit Update MPECs of the 11th and 13th from Mt. John Observatory in New Zealand on the 9th and 10th, and from David Tholen's team on Mauna Kea in Hawaii on the 9th.

Checking with the improved orbit data (MPEC 2005-R57), 2005 QQ87 still appears to be in resonance, its period tightly coupled to that of Earth, making annual close approaches (even slightly closer for the nominal value of this new orbit) during the next two to three decades. Again, this is for the nominal orbit, which still has large uncertainties.
      The search area for 2006 still remains large (several tens of degrees in RA and dec), making it difficult but not impossible, since the object should be bright. If the big surveys put effort into covering this area in late August next year, recovery is certainly possible, though not certain, I should say.
      I also note that the new H value suggest 2005 QQ87 could be slighty larger than initial results suggested, about 100 meters.

Risk monitoring:  A week ago Tuesday, on September 13th, observation of 2005 RQ6 was reported from the day before from Mt. John Observatory in New Zealand and North Ryde Observatory in New South Wales. With this, NEODyS and JPL removed the few impact solutions they had just posted for this half-kilometer object.
      On the 16th, the discovery of 2005 RD34 was announced in MPEC 2005-S04. It was posted that day by JPL as a risk, and the next day by NEODyS. This object, estimated by JPL at 300 meters wide, was discovered on the morning of the 15th by the Catalina Sky Survey in Arizona and confirmed the next morning from Table Mountain Observatory in southern California. Both risk monitors removed it on the 18th after the next observation was reported, from Great Shefford Observatory in England early the day before.
      With the bright Moon, there wasn't a lot of other risk monitoring news since A/CC's last news wrap on the 12th, but 2005 RR6 was reported on the 14th from the Spacewatch 1.8m telescope in Arizona on the morning of the 13th and on the 17th from Great Shefford early that day. On the 17th NEODyS removed this object, estimated at 660 meters wide, and JPL lowered its ratings for a single impact solution. It's rare for risk-listed objects like 2005 RR6 to be discovered with very large telescopes. See the next news item below to learn about the circumstances.
      A/CC's latest risk monitoring details, and links to more information, are posted on the CRT page, and updates are flagged via the A/CC RSS news feed (details below).

2005 RR6's discovery   by David Tholen
As A/CC reported on September 11th, 2005 RR6 was discovered by Fabrizio Bernardi. He is a postdoc employed in David Tholen's small solar elongation NEO search program, and who was working at Japan's 8.2m Subaru telescope on Mauna Kea in Hawaii at the time. Here is more of the story:

There is a bit of a story behind RR6. Murphy was determined to prevent us from securing the discovery. Our first exposure had the object in the gutter between CCDs of the SuPrime-Cam mosaic CCD camera. Our second exposure had the object on top of a star so bright that it saturated and bled along the columns of the CCD. Only in the third exposure was the object in the clear. Fortunately, subtraction of the second and third images, after alignment, suppressed the field star enough to where we could see the asteroid trail straddling the saturated bleed columns. Formal astrometry wasn't possible, but we could eyeball the beginning of the trail to perhaps half an arcsec.
      On our second night, fog set in just around the time that our observations were to start. Although the fog did eventually drop, there was trouble opening the dome. No observations were possible.
      By the third night, the MPC had already considered the object as hopeless. Their ephemeris uncertainty plots had the uncertainty region as large as 10 degrees. That, however, assumes a default astrometric uncertainty of 1.0 arcsec, and we do considerably better than that. I had estimated that we could recover the object in two SuPrime-Cam fields, if it was no closer than 0.15 AU from Earth, and less than four fields if it was no closer than 0.10 AU. Recovery did occur that night, and early enough so that we could schedule another set of observations as twilight came up, thereby giving us a little bit of parallax to work with.
      So, we recovered an object moving 230 arcsec per hour almost 3000 minutes after an 8 minute arc. Not bad.

As of last Saturday, 2005 RR6 has one low-rated impact solution remaining. See above.

[ previous news: 12 September 2005 ]
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