DBPS Anomaly

[bigmasterdrago]

I've been making ephemerides for close pass minor planets using the single MP search feature after getting info online. I tried using the DBPS just now for tomorrow night and came up with a list that does not include rocks from other sources. In particular 2021 RM5 and 2021 RF2. It includes only those below. Even when I broaden the magnitude to put them within reach, they are not included.

   

All of the 2010 rocks listed are from WISE discoveries with no orbits found, and short 10-14 day arcs. Except for 2010 OT146. Not sure where they even come from in the DBPS as I'm unable to find them in any lists of elements at Lowell, JPL or the MPC even after updating the MPC NEA Today and MPC NEA. Also doing a search for 2010 OG150 at https://minorplanetcenter.net/db_search   claims unknown object! I'm just at a loss when using the DBPS. Any guidelines would be helpful.

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And why 2003 QQ47, 2011 YQ10 & 1991 TF3 are not listed at https://cneos.jpl.nasa.gov/ca/ nor at https://spaceweather.com/ I can only guess is that the minimum distances are over 30LD.

[theskyhound]

Hello,

Its difficult for me to speak for 2021 RM5 and 2021 RF2 because I don 't have the orbits you are using. But I suspect that they are either not close enough or not bright enough at the exact moment in time that it is searching at. I'd check the magnitude parameters for these two asteroids too. If they are not set correctly then they won;t be bright enough.

To be honest, the Visual Edition DPS wasn't meant to do this sort of thing, so it doesn't have a means of specifying an exact time. Keep in mind that the date you specified is for the evening. I don't really know what you are trying to accomplish... it may be better to use the ephemeris instead.

[PMSchu]

Hi BMD,

I ran your DBPS with the parameters & results shown here: [attachment=2023]
& retreived 10 objects.

When I reduced the approach distance to <0.05 AU & removed the min brightness constraint, this was the result: [attachment=2024]
This is what I typically get; however, I don't normally see the objects detected by WISE.

When I removed the faint magnitude constraint, this was the result: [attachment=2025]
& retreived 444 objects, again with the WISE detections at the top of the list.

I don't know when or how these objects were included in the ST4 MP database. It may have been a while ago & they just remained there like 2010 CA261, which is now listed as 'Lost'. The search at MPC returns 'No Match'. It appears to have been 'Disappeared'. Maybe the other WISE objects have been treated similarly, I don't know.

I know that you are looking for fast movers, but since the duration of this fast motion can be so short, it seems better to search for MPs that come closer. They're more likely to move fast at close approach. Since they can also brighten, limiting the faint mag could elimnate good candidates too. When I calculate the ephemeris of the candidates that come within 0.05 AU, they frequently brighten by 4 or more magnitudes during the pass, so one that's 20 mag when you search, could become 15-16 mag in the future. Of course some that are 24 mag will only reach 20 mag too - the usual situation.

 You seem to reference many more online resources than I do. Take a look at the OL .stx file that I uploaded in the 2021 Rg19 thread to see what I mean about the rapid change  in brightness.

Hope this helps,

Phil S.

[bigmasterdrago]

It's clear from your search that the mag parameters, as Technoking mentioned, is what may have caused the loss of those two rocks. But when using Horizons or other ephemeris generating software, they were within the mag zone. I did notice the inclusion of those 2010 rocks that only had a 10-14 day arc in WISE data. Again lost rocks that I only found in a DBPS but no other. Thanks both of you.

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And one other mention. Those 2010 rocks were "no matching bodies found" using Horizons, Lowell, MPC, etc.

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Generally, I find the rapid brightness change caused primarily by illumination %. Although tonight 2021 RF2 remains near mag estimate 17.6 from 22:00CDT until dropping below my horizon after 3am after a close pass for me ~00:30 . Beginning high in the south and dropping to 30° in the SW. Phase% changes very little.

On the other hand, 2021 RM5 climbs out of the SE at mag ~19 peaking ~40° @~2am. Again remaining at a steady 93% phase. Both of these rocks are moving under 25"/min and beyond my reach visually.