The Asteroid/Comet Connection's
daily news journal about
asteroids, comets, and meteors
Today's issue status: done
Details: P/2004 F1, 2004.03.19 0:07 28x60 sec. J. Lacruz La Canada J87.
|Small objects – panel 1/2||Major News for 22 March 2004|
All the small objects that were tracked this last week — asteroids with absolute magnitude (brightness) H greater than 22.0 — were also newly announced in this period, beginning with 2004 EH1, which was announced Monday the 15th and was discovered the day before, to 2004 FE4, which had trumpets sounded yesterday, the 21st. Thirteen total. Two were discovered with the Spacewatch 0.9m telescope in Arizona and one by the Catalina Sky Survey (CSS), also in Arizona, and the other ten all by LINEAR in New Mexico.
Among this baker's dozen was 2004 FH, which made news headlines with the closest-ever observed Earth flyby on Thursday. It was the only intruder into the Earth-Moon system, but others got close. The Sormano Observatory SAEL shows 2004 FY3 at 2.1 lunar distances (LD) on March 17th, 2004 FY1 at 3.1 LD on Saturday, and 2004 EU22 at 5.1 LD on the 15th and 2004 EL20 at 5.7 LD the next day. And JPL shows that 2004 FA will fly by at 6.6 LD next Friday.
In addition to current observing, this last week also had positions reported for three H>22.0 objects from David Tholen's University of Hawaii team at Mauna Kea in October 2003.
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
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). All data used for the table is from Monday the 22nd, as some data was incomplete or unavailable on Sunday.
|News briefs – panel 1/1||Major News for 22 March 2004|
Manitoba event: A fireball was seen over Manitoba last night at about 7:30pm local, with reports specifically mentioning Regina and Oakbank. A CBC item today says "Dozens of people from central Manitoba to central Saskatchewan called the RCMP." See also Canoe today. RCMP officers describe the fireball as turquoise and split into pieces.
Planetary defense: Space.com has an article today, with the headline, "Asteroid Scare Prompts NASA to Formalize Response."
The plan [for notifying top officials], which has existed on an informal basis for months but was not known to all the key scientists involved, could be put out for review this summer and finalized by the end of the year. The blueprint will be limited to spelling out lines of communication within NASA.
FMO found & lost: The Spacewatch FMO Project reports that online volunteer Robert Klein in Maryland found an object October 20th moving at 18 degrees/day. With only two long trails to measure, it didn't reach the MPC NEO Confirmation page.
Observatory news: The Baxter Bulletin in "Petit Jean Mountain observatory celebrates its first anniversary" today reports that the Sherrod brothers have closed one observatory and are building a third, notes the scientific value of amateur astronomers' work, and has some drama: "the 1,700-pound telescope at Petit Jean has been struck by lightning twice and was narrowly missed by a tornado once."
If an object is large enough for gravity to round its shape, then it is no longer just a structure ruled by mechanical strength, like a rock, a building, or a mountain — instead, it is a wholly different kind of structure that we call a planet.
This keeps planetary status for Pluto and gives it to 1 Ceres and several distant objects (and big satellites?).
|Risk monitoring - panel 1/1||Major News for 22 March 2004|
The Monday Daily Orbit Update MPEC (DOU), which includes observations that would have been in Sunday's "abandoned" DOU, reports observation of 2004 FZ1 from LINEAR in New Mexico early Saturday, from Sandlot Observatory in Kansas early yesterday and this morning, and from Tenagra II Observatory in Arizona yesterday morning. Today NEODyS removed its impact solutions for this object.
The DOU also includes positions for 2004 FH from Sormano Observatory in Italy from the 18th, within the existing observation arc.
JPL has posted 2004 FU4, which was announced today in MPEC 2004-F49 as discovered Saturday morning by LINEAR and confirmed early yesterday by Sandlot Observatory and this morning by Tenagra II Observatory. JPL puts the diameter estimate at about 870 meters/yards wide.
Update: Before 7pm in Pasadena but after midnight UT, JPL has updated its risk assessment for 2004 FH based on observations reported in the Saturday and Monday DOUs, and is now down to a single very low-rated virtual impactor in 2098.