From pluto at projectpluto.com Thu Nov 7 17:10:39 2019 From: pluto at projectpluto.com (Bill Gray) Date: Thu, 7 Nov 2019 17:10:39 -0500 Subject: [neo_followup] A00001 = close-ish NEO Message-ID: Sorry, meant to post here as well : Hello all, ISON has found an interesting NEO. It shouldn't be difficult to follow up (assuming it's done quickly; it's fading), except that the NEOCP doesn't use earth/lunar perturbations. Often, that actually is not a big problem. Here, it is. If you use Scout or Find_Orb ephemerides, you'll get a correct position, one that ought to be right to within about ten arcseconds. Use the MPC position, and you'll be off by about a quarter degree. Also, note that the ISON astrometry doesn't specify a magnitude band. This object may be a bit fainter than the ephemerides suggest. -- Bill From planetaryscience at yahoo.com Sat Nov 23 12:37:49 2019 From: planetaryscience at yahoo.com (Sam Deen) Date: Sat, 23 Nov 2019 17:37:49 +0000 (UTC) Subject: [neo_followup] A10i6zC = geocentric transfer debris, probably related to ztf01nf References: <1287821163.4463772.1574530669953.ref@mail.yahoo.com> Message-ID: <1287821163.4463772.1574530669953@mail.yahoo.com> Hi all, the object A10i6zC on the NEOCP is pretty obviously an artsat: Perigee 2019 Nov 20.909404 +/- 0.0275 TT = 21:49:32 (JD 2458808.409404) Epoch 2019 Nov 21.0 TT = JDT 2458808.5 AutoNEOCP M 33.13518455 +/- 8 (J2000 equator) n 365.74775320 +/- 15.3 Peri. 193.14340 +/- 0.7 a 41797.3801 +/- 1165 Node 41.26207 +/- 0.21 e 0.6862850 +/- 0.0149 Incl. 32.72596 +/- 0.15 P1417.34m/0.984d H 32.7 G 0.15 U 14.6 q 13112.4616 +/- 1008 Q 70482.2986 +/- 1379 >From 5 observations 2019 Nov. 21 (46.9 min); mean residual 0".16and based on the orbit, I figured I'd check if it was any one of the many geocentric transfer debris we know of. The best fit I could find was ztf01nf, discovered around this time last year: www.projectpluto.com/pluto/mpecs/ztf01nf.htm Perigee 2018 Nov 14.679965 +/- 0.00239 TT = 16:19:09 (JD 2458437.179965) Epoch 2018 Nov 15.0 TT = JDT 2458437.5 Gray M 120.40721599 +/- 0.58 (J2000 equator) n 376.23157195 +/- 1 Peri. 200.98066 +/- 0.06 a 41017.2633 +/- 72.9 Node 37.37637 +/- 0.0018 e 0.7805021 +/- 0.000384 Incl. 32.97280 +/- 0.0054 P1377.85m/0.957d H 34.4 G 0.15 U 12.7 q 9003.20195 +/- 28.5 Q 73031.3248 +/- 121 >From 6 observations 2018 Nov. 15 (3.2 hr); mean residual 0".417the main problem with the linkage is that the eccentricity seems to have inexplicably decreased while keeping the semimajor axis roughly the same. Otherwise, the linkage seems pretty solid. ~Sam -------------- next part -------------- An HTML attachment was scrubbed... URL: From pluto at projectpluto.com Sat Nov 23 13:44:06 2019 From: pluto at projectpluto.com (Bill Gray) Date: Sat, 23 Nov 2019 13:44:06 -0500 Subject: [neo_followup] A10i6zC = geocentric transfer debris, probably related to ztf01nf In-Reply-To: <1287821163.4463772.1574530669953@mail.yahoo.com> References: <1287821163.4463772.1574530669953.ref@mail.yahoo.com> <1287821163.4463772.1574530669953@mail.yahoo.com> Message-ID: Hi Sam, all, On 11/23/19 12:37 PM, Sam Deen wrote: > the object A10i6zC on the NEOCP is pretty obviously an artsat: Yup, kinda puzzling that it's still on NEOCP. I assume MPC will remove it soon as "not a minor planet". I ran the object through Sat_ID, of course, though without any success in matching it to a known object that way. > Perigee 2019 Nov 20.909404 +/- 0.0275 TT = 21:49:32 (JD 2458808.409404) > Epoch 2019 Nov 21.0 TT = JDT 2458808.5 AutoNEOCP > M 33.13518455 +/- 8 (J2000 equator) > n 365.74775320 +/- 15.3 Peri. 193.14340 +/- 0.7 > a 41797.3801 +/- 1165 Node 41.26207 +/- 0.21 > e 0.6862850 +/- 0.0149 Incl. 32.72596 +/- 0.15 > P1417.34m/0.984dH 32.7 G 0.15 U 14.6 > q 13112.4616 +/- 1008 Q 70482.2986 +/- 1379 > From 5 observations 2019 Nov. 21 (46.9 min); mean residual 0".16 > > and based on the orbit, I figured I'd check if it was any one of the many geocentric transfer debris we know of. The best fit I could find was ztf01nf, discovered around this time last year: You may be on to something there. It is _very_ difficult to say, though. If this is an "empty trash bag object", its current orbit would be a somewhat scrambled version of what it was a year ago. There is, for example, no real chance of linking the two (unless, _maybe_, more data comes up.) However, as an ETBO, the change in eccentricity would be easy to explain. ETBOs tend to change quickly in inclination and eccentricity. (Which can make it nearly impossible to link apparition A to apparition B, unless the two apparitions are closely spaced enough that the orbits still look vaguely similar.) But it's hard for solar radiation pressure to add to or subtract from the total energy, i.e., the semimajor axis. It seems that anything it gains on half the orbit (withthe sun "at its back"), it loses on the other half of the orbit ("going into a headwind"). -- Bill > www.projectpluto.com/pluto/mpecs/ztf01nf.htm > > Perigee 2018 Nov 14.679965 +/- 0.00239 TT = 16:19:09 (JD 2458437.179965) > Epoch 2018 Nov 15.0 TT = JDT 2458437.5 Gray > M 120.40721599 +/- 0.58 (J2000 equator) > n 376.23157195 +/- 1 Peri. 200.98066 +/- 0.06 > a 41017.2633 +/- 72.9 Node 37.37637 +/- 0.0018 > e 0.7805021 +/- 0.000384 Incl. 32.97280 +/- 0.0054 > P1377.85m/0.957dH 34.4 G 0.15 U 12.7 > q 9003.20195 +/- 28.5 Q 73031.3248 +/- 121 > From 6 observations 2018 Nov. 15 (3.2 hr); mean residual 0".417 > > the main problem with the linkage is that the eccentricity seems to have inexplicably decreased while keeping the semimajor axis roughly the same. Otherwise, the linkage seems pretty solid. > > ~Sam >