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Centaur
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NEO Asteroid Recovered - New Parameters Determined
      #5617559 - 01/11/13 04:29 PM

Asteroid 2012 DA14 has been recovered and new parameters have been determined. Last night I e-mailed Italian professor Aldo Vitagliano, the creator of the Solex astronomical numerical integration program. This morning he sent me the newly updated vectors of the 45-meter asteroid for inclusion in Solex.

His new nominal solution indicates that the closest approach to the Earth’s center will occur at exactly the same time as the previous best estimate: 2013 FEB 15 at 19:25:49 TD (19:24:42 UT). However, the distance to the Earth’s center at that time is now estimated to be 34,112 km rather than the earlier estimate of 34,373 km. The point on Earth where the asteroid will be in the zenith at that time is in the Indian Ocean west of Sumatra at E 96.595° & S 6.238°. The previous estimate was E 97.153° & S 6.360°.

In both cases, the estimated greatest brilliance for the point on Earth closest to the asteroid is magnitude +7.0. Interestingly, both the current and previous estimates for Perth, Australia at the moment of closest approach to the Earth’s center are magnitude +6.9. Even though Perth will be a little further from the asteroid, from Perth’s perspective the asteroid will be nearer to opposition from the Sun which increases the illumination.

Aldo notes that while the new parameters are hardly different from the previous ones, the uncertainties have been dramatically reduced. He says that the chance of an impact with Earth in 2040 is now zero. He indicates that another close approach without impact will occur in 2046.

I've updated my related graphics at: www.CurtRenz.com/asteroids

Edited by Centaur (01/11/13 07:30 PM)


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Mark9473
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Re: NEO Asteroid Recovered - New Parameters Determined new [Re: Centaur]
      #5622651 - 01/14/13 01:04 PM

I see that I'm not too far from the zenith line (Europe) but unfortunately the object will be almost mag 11 when it culminates. It rises for me at magnitude 7.6 and would be mag 8 at 25 degree altitude. Will be nice to chase it down with binoculars.

Do you know a site that plots a topocentric star chart of its track against the stars? I used JPL's Horizon's website for an ephemeris but that's just a list of numbers.

Alternatively, would you know if the currently available orbital elements allow a correct trajectory to be calculated shortly after closest approach or does this additionally require a calculation of the effects of Earth's gravity on the changing orbital elements?


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Centaur
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Re: NEO Asteroid Recovered - New Parameters Determined new [Re: Mark9473]
      #5622868 - 01/14/13 03:17 PM

Quote:

I see that I'm not too far from the zenith line (Europe) but unfortunately the object will be almost mag 11 when it culminates. It rises for me at magnitude 7.6 and would be mag 8 at 25 degree altitude. Will be nice to chase it down with binoculars.

Do you know a site that plots a topocentric star chart of its track against the stars? I used JPL's Horizon's website for an ephemeris but that's just a list of numbers.

Alternatively, would you know if the currently available orbital elements allow a correct trajectory to be calculated shortly after closest approach or does this additionally require a calculation of the effects of Earth's gravity on the changing orbital elements?




Mark, regarding a publicly available topocentric star chart for this asteroid, I know of none. That does not mean they do not exist. I have the ability to create them for my own use with my self-made software. But I am not doing that for this comet for four reasons. First, I’ll be on the opposite side of the world. Second, the position jumps will be huge in just minutes. Third, the orbital parameters could still be changed a bit as the rendezvous approaches. And fourth, I have no problem consulting “just a list of numbers”. Those numbers can be used to draw positions on a star chart. Just be certain that the list of numbers is based on numerical integration and not osculating orbital elements for an epoch earlier than the closest approach.

The diagram I created of an “overhead” view of the orbits utilizes three different osculation epochs from the Solex numerical integration program. They are for the moment of closest approach and 120 days on either side. Of course that could also be done for the hours following the closest approach. I specifically requested revised orbital parameters from the creator of Solex to enter into my copy of his program. He is Cloudy Nights message board member Aldo Vitagliano who participates with his real name. Here’s a link to another Cloudy Night’s thread in which he was discussing this asteroid: http://www.cloudynights.com/ubbthreads/showflat.php/Cat/0/Number/5570752/page...


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Mark9473
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Re: NEO Asteroid Recovered - New Parameters Determined new [Re: Centaur]
      #5623031 - 01/14/13 04:36 PM

Thanks Curt. Guess I'll run the Horizons website again just a few days before the event, and then plot a chart myself as you suggested.

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