2021-09-29, 04:44 PM
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.
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.