Although some work was done on 16 nights in August, many sessions were interrupted by cloud with just a couple of nights judged as good. Most of the NEOs followed were observed on single nights only, the exception being Apollo 2006 ON1 with three nights.
Apollo 2006 QV89 was observed while it was on the NEOCP and is interesting because its minimum orbital intersection distance with the Earth (MOID) is currently given as 0.00001 AU or about 1,000 miles. At the time of writing (Sep 5th) it is listed with a 1 in ~800 chance of collision with Earth in 2019, so just as well it is only about 30 metres in diameter... Further positions in the coming days are desirable.
On Aug 29th positions for 6Q0B44E were obtained, discovered by the Catalina survey the day before and subsequently found to be in an unstable 80 day orbit around the Earth. It is still unclear whether this is an artificial satellite re-captured by the Earth similar to the Apollo 12 S-IVB third stage J002E3 back in 2003 or whether it is a very small (1-5 metre diameter) NEO temporarily captured by Earth. As noted by Bill Gray, with the current data, it looks as if this object probably entered the Earth/Moon system sometime between about 2000 and 2003, though dates as far back as 1991 are quite possible. Paul Chodas (JPL) comments that it will stay in Earth orbit for at least three more years.
Tuesday, 5 September 2006
Tuesday, 1 August 2006
2006 July notes
With the summer monsoon having taken hold in the southern USA, stopping the big surveys from operating for most of the month, time was spent catching some NEOs at their second and subsequent oppositions.
Working with Roger Dymock we also went after some more normal main belt minor planets on the FUAP (Follow Up Astrometric Program) target list at http://asteroidi.uai.it/ which is maintained by Sergio Foglia on behalf of the UAI Minor Planets Section. This site lists minor planets of mag +18.5 or brighter that are in need of observation, whether newly discovered and under-observed, or awaiting recovery at their second or subsequent oppositions.
The last week of the month saw a flurry of NEO discoveries from the surveys in a brief respite from their bad weather, with several objects at mag 16-17.
Working with Roger Dymock we also went after some more normal main belt minor planets on the FUAP (Follow Up Astrometric Program) target list at http://asteroidi.uai.it/ which is maintained by Sergio Foglia on behalf of the UAI Minor Planets Section. This site lists minor planets of mag +18.5 or brighter that are in need of observation, whether newly discovered and under-observed, or awaiting recovery at their second or subsequent oppositions.
The last week of the month saw a flurry of NEO discoveries from the surveys in a brief respite from their bad weather, with several objects at mag 16-17.
Wednesday, 28 June 2006
2006 June notes: 2006 KZ112 and 2006 MU6
Several objects were followed over a period of a couple of weeks during the month, including 2006 KZ112 which has an interesting 'Encke like' orbit (2006 KZ112: q=0.29, e=0.89, i=38, P=4.0, Encke: q=0.33, e=0.85, i=12, P=3.3).
Of the other objects observed, 2006 MU6 was picked up on June 27 after being discovered by Spacewatch on June 20th and is a possible Mars Trojan (though the uncertainties on the orbital elements are still large). Already very faint it is predicted to fade quickly.
Of the other objects observed, 2006 MU6 was picked up on June 27 after being discovered by Spacewatch on June 20th and is a possible Mars Trojan (though the uncertainties on the orbital elements are still large). Already very faint it is predicted to fade quickly.
Saturday, 3 June 2006
2006 May notes: 2006 JE, 2006 GY2, 2006 HX57, 2006 JV26 and 2006 JF42
May was on the way to being my worst month since Nov 2003 until the unsettled spell finally ended on 27 May and four of the last five nights were clear.
The month had started well with some fast movers - 2006 JE was a LINEAR discovery that I managed to confirm when it was on the NEOCP, about 1/2 degree off track and moving at 94"/min. A much easier target because it was over 4 mags brighter at +14.0 but travelling at about the same speed was 2006 GY2 on May 15.9, just a few hours before it passed 7 lunar distances from Earth and the same time as it was being observed from Arecibo and Goldstone and found to be a binary with components of 400 m and 80 m diameter. 2006 HX57 was observed on May 6.0 at mag 16.5, moving at 92"/min and also 2006 JV26 on May 8.9 at mag 16.5 and moving at 290"/min, less than 3 lunar distances away.
An interesting object discovered on May 11 by the Catalina Sky Survey was 2006 JF42, observed from May 15-31, deep in the glow of evening twilight. It has a very short period of only 201 days (shorter than Venus) but with an eccentric orbit taking it from 0.28 AU at perihelion to 1.06 AU at aphelion, with the most favourable viewing circumstances being when aphelion occurs around May 21, when it would be placed in the opposition region of the sky south of the ecliptic. This year aphelion was only two weeks later but the best elongation achieved was only 96 degrees.
The month had started well with some fast movers - 2006 JE was a LINEAR discovery that I managed to confirm when it was on the NEOCP, about 1/2 degree off track and moving at 94"/min. A much easier target because it was over 4 mags brighter at +14.0 but travelling at about the same speed was 2006 GY2 on May 15.9, just a few hours before it passed 7 lunar distances from Earth and the same time as it was being observed from Arecibo and Goldstone and found to be a binary with components of 400 m and 80 m diameter. 2006 HX57 was observed on May 6.0 at mag 16.5, moving at 92"/min and also 2006 JV26 on May 8.9 at mag 16.5 and moving at 290"/min, less than 3 lunar distances away.
An interesting object discovered on May 11 by the Catalina Sky Survey was 2006 JF42, observed from May 15-31, deep in the glow of evening twilight. It has a very short period of only 201 days (shorter than Venus) but with an eccentric orbit taking it from 0.28 AU at perihelion to 1.06 AU at aphelion, with the most favourable viewing circumstances being when aphelion occurs around May 21, when it would be placed in the opposition region of the sky south of the ecliptic. This year aphelion was only two weeks later but the best elongation achieved was only 96 degrees.
Friday, 5 May 2006
2006 April notes: Integral, 2006 GA, 2006 GC, Comet 73P/Schwassmann-Wachmann
April was a much better month than the last few, with 19 usable nights.
The artificial satellite Integral wandered into the field of component 73P-N/Schwassmann-Wachmann on the morning of April 12th, moving at about 230"/min. Not knowing whether it was a close approaching NEO or a very unusual artificial satellite I followed it for 50 minutes until it ran into bright twilight, which was long enough to work out an orbit for it and to pick it up again 2 nights later. Thanks go to Tony Beresford and Mike McCants for identifying it for me.
A couple of NEOs were followed for several weeks (2006 GA & 2006 GC) but most were observed for much shorter arcs. A fair proportion of the early mornings during the month were spent imaging over 30 of the components of 73P as it approached the Earth.
The artificial satellite Integral wandered into the field of component 73P-N/Schwassmann-Wachmann on the morning of April 12th, moving at about 230"/min. Not knowing whether it was a close approaching NEO or a very unusual artificial satellite I followed it for 50 minutes until it ran into bright twilight, which was long enough to work out an orbit for it and to pick it up again 2 nights later. Thanks go to Tony Beresford and Mike McCants for identifying it for me.
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| Artificial Satellite Integral passes through the field of view of faint fragments of comet 73P/Schwassmann-Wachmann |
A couple of NEOs were followed for several weeks (2006 GA & 2006 GC) but most were observed for much shorter arcs. A fair proportion of the early mornings during the month were spent imaging over 30 of the components of 73P as it approached the Earth.
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