Archive for September, 2010

MPC statistic for September 2010

The new monthly MPC circular released – MPC 71889- 72344.

ISON-NM statistic for the previous month (August 22 – September 16):

Number of measurements: 9502

Measured objects: 2232

Discovered objects: 6 (2010 RF34; 2010 RZ79; 2010 RN80*; 2010 RU164; 2010 RF166; 2010 RO166)

Sky coverage: 610 sq. degrees

Observing nights**: 16

* – interested object (NEO)

** – include partial nights

Another interesting discovery of Solar System object

Today another interesting discovery made by the now-defunct WISE (Wide-Field Infrared Survey Explorer) became known. Measurements of the newly discovered object were made January 30 and 31, 2010. The object having the preliminary designation 2010 BK118, had a preliminary orbit, the so-called V?is?l? orbit, named for the Finnish astronomer, Yrj? V?is?l?, who developed the method.

Objects having this type of orbit are not included in the common catalogs of orbital elements of Solar System objects such as MPCORB or ASTORB. To obtain a full orbit, a third night of observations is needed, but it didn’t happen; the object was lost…September 19, 2010 the American sky survey, LINEAR (Lincoln Near-Earth Asteroid Research), discovered a rather bright object (~19th mag. at time of discovery) with an unusual orbit, receiving the preliminary designation BV17485. After confirmation of the object by several observatories around the world and establishing a preliminary orbit, scientists were able to tie it to the orbit of the object lost at the beginning of the year – 2010 BK118. After which the so-called “observation arc”, that is, the period of time between the first and last observations, exceeded 7.5 months, which allowed for sufficient accuracy in calculating the orbit. It became apparent that this was a unique object. The semi-major axis of its orbit is equal to 293.76 a.u. – a total of 9 of all the known objects on the Solar System have a larger semi-major axis. However, all these objects orbit in “normal” prograde orbits. 2010 BK188 orbits backwards, i.e. it has a rare retrograde orbit. The large eccentricity of the orbit (0.98) of this object is characteristic of such distant record-makers – for all objects having a semi-major axis of more than 200 a.u., the eccentricity of the orbit is greater than 0.82.

It is worth noting that one of the known objects – 2010NV1, by the way, discovered in 2010, also by the cosmic telescope WISE after the initial discovery of 2010 BK118, had similar orbital parameters. But the semi-major axis of 2010 BK118 is larger by 20 a.u. Additionally, the perihelion distance, the minimum distance that the object approaches the Sun, is less than 3.3 a.u. – 2010 BK118 passes close to Jupiter at the same time as 2010 NV1 to Saturn.

On both objects there was no sign of cometary activity found, possibility its appearance is prevented by its veery distant location from the Sun. The orbital period of these objects around the center of the Solar System exceeds 5000 and 4500 years correspondingly. and they both belong to the so-called population of scattered disk objects (SDO), but they differ in their extremely small perihelion distance.

Orbit Viewer

Halley’s comet was observed by ancient Greeks?

I would like to share with the reader a short analysis of an article in the Journal of Cosmology about the possible connection of the so-called Comet of the 78th Olympiad observed by the ancient Greeks in 466 B.C. and the comet which today is known as Halley’s comet. The article was interesting to me, but quite frankly, the original didn’t have much credibility. There was not a word about how scientists calculated the position of the comet 2500 years ago, nor any technical description.
I tried to get similar results with the help of the JPL HORIZONS system. Taking the osculating elements of the comet for 239 B.C. (SAO/-239), I used back integration of the position of the comet 227 years ago (JPL DE406).
Actually, it seems that Comet Halley passed by the Earth in 466 B.C. Its minimum distance from the Earth was at the end of June – beginning of July, passing at a distance of 0.48 A.U. (71.8 million km). The comet was visible to the unaided eye from June to August. At the beginning and end of the first two summer months, the Moon didn’t interfere with finding the comet in the dark skies of Chalcis. My estimate of the brightness of the comet is a little higher than that of Graham and Hintz (Graham et al., Journal of Cosmology 2010, Vol. 9). Its maximum brightness would have been mag. 2, but that, of course, is a complex issue and here the fact that we are working with 2500 year-old data plays a major role, in other words, some 33 orbits of the comet around the Sun in which each time the comet approached the Sun, it lost more and more material.
At the beginning of June, Halley was visible low in the pre-dawn sky. By the end of June, the comet had moved to the evening sky and it was visible low above the horizon, not more than 10 degrees. Since it had decreased in brightness, it had already became a difficult object to observe. From this information, I support the hypothesis that the ancient Greeks observed only the “young” (of course by man’s reckoning) Comet Halley. There would still be 2244 years until its “discovery”…

(Russian) Сайту обсерватории ISON-NM полгода

New TNO finded on Hubble archive images

Astronomers from Harvard-Smithsonian Center for Astrophysics, using clever techniques to cull the data archives of Hubble Space Telescope have added 14 new Trans-Neptunian objects to the catalog. Their method promises to turn up hundreds more. The team developed software to analyze hundreds of Hubble images hunting for such streaks. After promising candidates were flagged, the images were visually examined to confirm or refute each discovery. Most TNOs are located near the ecliptic — a line in the sky marking the plane of the solar system (since the solar system formed from a disk of material). Therefore, the team searched within 5 degrees of the ecliptic to increase their chance of success. They found 14 objects, including one binary. All were very faint, with most
measuring magnitude 25m-27m.  The newfound TNOs range from 25 to 60 miles (40-100 km) across. Perhaps this is the most smallest TNO objects, discovered at this time.

September 2010
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