Enroute for 57 months and still 16 months away from the Jupiter system, the Galileo spacecraft on this day 13 years ago caught the flash of the last known of 20-plus fragments that hit Jupiter from comet Shoemaker-Levy 9. These images in green light are, from left to right, 2-1/3 seconds apart. Credit: NASA JPL/Galileo.
Contents on 22 July '07
- Minor-Object News -- two items
- Minor-Object Science -- one paper
- IAU Minor Planet Center
- Impact Risk Monitoring -- one object reported
- Consolidated Risk Tables - CRT page
- Ephemerides for risk-rated objects
- Ephemerides for small asteroids
Navigation tips: Use the << and >> arrows on the menus for each regular section (Observers, Risks, etc.) to move to the previous and next day's news for that section. Use the Index menu item to access specific days this year through a calendar interface. And use the all-up news archive to access news from any time since A/CC began in early 2002. To keep track of what's new each day, watch the Chronology section.
Minor-Object News on 22 July '07
- Asteroid discoveries (updated): Late today UTC the Minor Planet Center announced the discoveries of two asteroids. One of these, 2007 OG3 (see below), has now been posted by JPL as a very low-rated impact risk -- see details below. This object was discovered three mornings ago by the Catalina Sky Survey in Arizona and confirmed early yesterday and today from the central U.S.
The other discovery (see below) is classified as small, estimated from standard formula to be very roughly 40 meters in diameter. JPL reports that 2007 OH3 passed Earth at about 13.3 lunar distances two days ago, which was a little more than three hours before it was discovered by LINEAR in New Mexico. Confirmation observations came from Europe, the South Pacific, and the east-central U.S. and California. This is only the third small-asteroid discovery so far this month.
- Bits & pieces: When nights are short, as they are now in the northern hemisphere where most NEO observing is done, and when you are clouded out, which is common this time of year in the U.S. southwest from where most NEO discoveries are made, there is still useful work to be done in the archives. In the last two days only two MPECs have been issued for individual objects. One came from the work of Rob Matson, who backtracked this year's discovery, 2007 GD49, to find it in the archives from the JPL NEAT program's Air Force telescope on Haleakala in Hawaii from April and May four years ago (see link). This is his second MPEC for July, after 2007 LV (link), which he found in images from NEAT's Mt. Palomar telescope from April-May 2002. So far this year there have been eight other MPECs issued with Matson's archival astrometry, and his work has also been published in two MPECs for comets discovered in SOHO online images.
Great Shefford Observatory has posted an animation of the challenging observation of comet C/2007 O1 (LINEAR) from two 17- and 16-frame stacks of 16-sec. exposures from June 17th.
From the weight of publicly available papers it sure seems like there is a lot more science being published these days about disks around other stars than about studying objects from the disk closest to home, comprised of our own Main Belt and Kuiper Belt as well as zodiacal dust and "the scattered disk" (Centaurs, comets, etc.). But it is all completely interrelated, and a good way to get up to speed on the terminology used and the state of current knowledge about exo-disks is to visit Paul Kalas's Circumstellar Disk Learning Site. He was the lead author on the "blue needle" disk that got much news coverage on July 19th. See more below about the related science paper.
Minor-Object Science on 22 July '07
- "Discovery of extreme asymmetry in the debris disk surrounding HD 15115" by Kalas, Paul with Michael P. Fitzgerald & James R. Graham, abstract & PDF at arXiv.org April 2007 - Quote: "We report the first scattered light detection of a dusty debris disk surrounding the F2V star HD 15115 using the Hubble Space Telescope in the optical, and Keck adaptive optics in the near-infrared. The most remarkable property of the HD 15115 disk relative to other debris disks is its extreme length asymmetry. The east side of the disk is detected to ~315 AU radius, whereas the west side of the disk has radius >550 AU." - Note: See also related news releases and news media reports on July 19th.
NEOCP Activity on 22 July '07
The MPC's NEO Confirmation Page has 4 listings: 1 new, 3 updated
When last checked at 2259 UTC today, the Minor Planet Center's NEO discovery Confirmation Page (NEOCP) had one new and three updated listings. Of these, two were "one nighters." Major News counted a total of nine objects listed on the NEOCP at some point on this day.
New MPECs on 22 July '07
Minor Planet Electronic Circulars
There were four MPECs issued this day from the International Astronomical Union's Minor Planet Center in Cambridge, Massachusetts.
- MPEC 2007-O36 time-stamped "06:07 UT" - Daily Orbit Update - see below
- MPEC 2007-O37 time-stamped "16:21 UT" - 2005 OE3 - see below
- MPEC 2007-O38 time-stamped "18:35 UT" - 2007 OG3 - see below
- MPEC 2007-O39 time-stamped "18:37 UT" - 2007 OH3
MPEC 2007-O39 - "18:37 UT" - 2007 OH3
- K07O03H 2007 OH3 (small asteroid, H=24.6 ~41m) was discovered at 0521 UT 20 July by LINEAR, which observed it at July 20.22-27p5. The discovery was confirmed by Farra d'Isonzo Obs. (July 20.90-91p2 & 20.00-02p2), Remanzacco Obs. (July 20.92-97p5, 21.04p1 & 22.01-02p2), Cordell-Lorenz Obs. (July 21.26p2 & 22.23-28p5), Jim Young via Table Mtn. Obs. (July 21.28-30p4), Astronomical Research Obs. (ARO) (July 21.29-30p3), Farpoint Obs. (July 21.37p3), Alter Satzberg Obs. (July 21.96-98p3), Mt. John Obs. (July 22.39p3), and the Siding Spring Survey (SSS) (July 22.48p2).
MPEC 2007-O38 - "18:35 UT" - 2007 OG3
- K07O03G 2007 OG3 (risk-listed, H=18.6 ~645m) was discovered at 1047 UT 19 July by the Catalina Sky Survey (CSS), which observed it at July 19.45-47p7. The discovery was confirmed by ARO (July 21.38p3 & 22.38p3) and Farpoint Obs. (July 21.39-40p4).
MPEC 2007-O37 - "16:21 UT" - 2005 OE3
- K05O03E 2005 OE3 (H=20.2 ~309m) from Young/Table Mtn. (July 19.46-48p3 & 20.46-48p3)
- K07O00X 2007 OX (arc=3 days, H=21.1 ~204m) from Wildberg Obs. (July 18.99-00p2) and ARO (July 21.33p3)
- K07N00Q 2007 NQ (arc=10 days, H=19.5 ~426m) from Santa Mama Obs. (July 20.86-90p3)
- K07M24B 2007 MB24 (i=47.7°, arc=26 days, H=18.3 ~741m) from New Millennium Obs. (July 19.96-00p9)
- K07L32R 2007 LR32 (arc=57 days, H=17.3 ~1.17 km) from New Millennium Obs. (July 20.01-07p11)
- K07L00V 2007 LV (arc=2 opp, H=18.2 ~776m) from SSS (July 21.55-56p4)
- K07DA3T 2007 DT103 (arc=144 days, H=18.6 ~645m) from Simeis Astrophysical Obs. (July 19.81-83p21)
- K07C26K 2007 CK26 (arc=2 opp, H=19.1 ~513m) from Santa Mama Obs. (July 20.96-97p3)
- K04S09T 2004 ST9 (arc=2 opp, H=18.0 ~851m) from New Millennium Obs. (July 19.96-00p10)
- K03SM2W 2003 SW222 (arc=3 opp, H=17.2 ~1.23 km) from ARO (July 21.31-32p3)
- K03M09T 2003 MT9 (q=0.200 AU, Q=4.874 AU, arc=2 opp, H=18.6 ~645m) from North Obs. (July 18.93-94p3), Santa Mama Obs. (July 19.87-90p4 & 20.93-94p4), and Lumezzane Obs. (July 20.96p4)
- K01R17V 2001 RV17 (arc=2 opp, H=20.3 ~295m) from Lumezzane Obs. (July 20.94-95p4)
- K01F90D 2001 FD90 (arc=3 opp, H=19.1 ~513m) from ARO (July 21.32-34p3)
- J99V22G 1999 VG22 (arc=5 opp, H=18.7 ~616m) from ARO (July 21.29-32p3)
- D6818 136818 1997 MW1 from New Millennium Obs. (July 19.92-95p4)
- 86324 86324 1999 WA2 from Galaxy Blues Obs. (July 22.10-14p2 & 22.18p1)
- 85275 85275 1994 LY from New Millennium Obs. (July 19.90-99p11)
- 24443 24443 2000 OG from CAST Obs. (July 19.89p1)
Observers on 22 July '07
Nineteen observing facilities appeared in this day's MPECs.
|B03||Alter Satzberg Obs. in Austria, 1 in MPEC 2007-O39 -- 2007 OH3|
|H55||Astronomical Research Obs. in Illinois, 6 in MPECs 2007-O36, 2007-O38 & 2007-O39 -- 2007 OH3, 2007 OG3, 2007 OX, 2003 SW222, 2001 FD90, 1999 VG22|
|235||CAST Obs., 1 in MPEC 2007-O36 -- 24443|
|703||Catalina Sky Survey in Arizona, 1 in MPEC 2007-O38 -- 2007 OG3|
|850||Cordell-Lorenz Obs. in Tennessee, 1 in MPEC 2007-O39 -- 2007 OH3|
|734||Farpoint Obs. in Kansas, 2 in MPECs 2007-O38 & 2007-O39 -- 2007 OH3, 2007 OG3|
|595||Farra d'Isonzo Obs. in Italy, 1 in MPEC 2007-O39 -- 2007 OH3|
|H89||Galaxy Blues Obs. in Ontario, 1 in MPEC 2007-O36 -- 86324|
|704||LINEAR in New Mexico, 1 in MPEC 2007-O39 -- 2007 OH3|
|130||Lumezzane Obs. in Italy, 2 in MPEC 2007-O36 -- 2003 MT9, 2001 RV17|
|474||Mt. John Obs. in New Zealand, 1 in MPEC 2007-O39 -- 2007 OH3|
|A24||New Millennium Obs. in Italy, 5 in MPEC 2007-O36 -- 2007 MB24, 2007 LR32, 2004 ST9, 136818, 85275|
|J69||North Obs. in England, 1 in MPEC 2007-O36 -- 2003 MT9|
|473||Remanzacco Obs. in Italy, 1 in MPEC 2007-O39 -- 2007 OH3|
|B38||Santa Mama Obs. in Italy, 3 in MPEC 2007-O36 -- 2007 NQ, 2007 CK26, 2003 MT9|
|E12||Siding Spring Survey in New South Wales, 2 in MPECs 2007-O36 & 2007-O39 -- 2007 OH3, 2007 LV|
|094||Simeis Astrophysical Obs. in Ukraine, 1 in MPEC 2007-O36 -- 2007 DT103|
|6735||Jim Young via Table Mtn. Obs. in southern California, 2 in MPECs 2007-O37 & 2007-O39 -- 2007 OH3, 2005 OE3|
|198||Wildberg Obs. in Germany, 1 in MPEC 2007-O36 -- 2007 OX|
Impact Risk Monitoring on 22 July '07
Notes for Today's Latest Risk Assessments
|2007 OG3||JPL||2259||2040||1||7.4e-10||-6.67||-6.67||0||JPL: "Analysis based on 17 observations spanning 2.9331 days (2007-Jul-19.44939 to 2007-Jul-22.382539)." Diameter approximately 0.390 km. from mean, weighted H=19.7.|
An impact solution, also known as a "virtual impactor" (VI), is not a prediction but rather a possibility derived from an orbit calculation that cannot be eliminated yet based on the existing data. Elimination can come quickly with just a little further observation or may take weeks or months, sometimes years. Once superceded or eliminated, a former impact solution has zero relevance to an object's risk. See Jon Giorgini's "Understanding Risk Pages" for more about this.
Chronology on 22 July '07
Times are UTC for when the items were noted or added by Major News.
|2259||Noted that JPL has posted 2007 OG3 as an impact risk - see above|
|2131||Added news report, "Asteroid discoveries (updated)"|
|2059||Grabbed MPEC 2007-O38 - 2007 OG3 - see above|
Grabbed MPEC 2007-O39 - 2007 OH3 - see above
|1824||Added MOS paper, "Discovery of extreme asymmetry in the debris disk surrounding HD 15115" - see above|
Added news report, "Bits & pieces"
|1719||Grabbed MPEC 2007-O37 - 2005 OE3 - see above|
|1438||Grabbed MPEC 2007-O36 - Daily Orbit Update - see above|