"Pseudo-MPEC" for ZTF00V9 = ZTF00Vv = ZTF00Y5
Created 2018 Sep 8 20:03:38 UT using Find_Orb
Click here for an explanation of pseudo-MPECs
TLEs are available for this and other objects on these pages. Be warned that, for reasons discussed below, the TLEs for this particular object may not be all that good.
This Zwicky Transient Facility object was found first as ZTF00V9, then recovered two days (and two orbits) later as ZTF00Vv. The orbital elements matched well enough to make the linkage "obvious", but a straightforward linkage resulted in mean residuals of 103 arcseconds.
Including solar radiation pressure got a much more reasonable orbit, with a truly huge area/mass ratio of about 95 m^2/kg. If the object really is about a meter across, as its brightness suggests, it would have a mass of about ten grams. It could be a piece of insulation, for example.
The object was found a third time on 2018 September 2, with further data six days later from Marco Micheli at (J04) in Tenerife. As shown below, you can't really fit all the arcs, though they fit pairwise nicely. There are almost certainly some "sideways" forces, and inconsistent area presented to the sun, that are not being modeled here. The exact value depends on which arcs you use, but the area/mass ratio is still somewhere around 90 m^2/kg.
Deepening the mystery, ZTF found ZTF00Y9 = ZTF00Yp = ZTF00ah and ZTF00hf = ZTF00YB at roughly the same time, and they're also small, lightweight bits in roughly one-day orbits.
Predicting the path of this object is a bit like trying to predict where a plastic bag will go when it's being blown down the street. You know it'll mostly go with the wind, but it'll do some unpredictable moves as well. (Which is why I'm now referring to these objects as "ETBOs", for "Empty Trash Bag Objects". As of 2018 September 21, ZTF has found four of them, with area/mass ratios of about 20 to 100 m^2/kg.) This happens to match reasonably well with the area/mass ratio of some aluminized plastic insulation, and that's probably what these are.
So don't take the ephemerides or TLEs (for any ETBO) too seriously. Not only are there probably significant errors; I don't even have a way to evaluate how great those errors might be (could be arcseconds, could be several degrees). I often compute TLEs for such objects that are good enough to identify the object a few weeks later, but they usually get away from me eventually.
I've since learned that such objects are fairly well-known in the SSA (Space Situational Awareness) community, and have been referred to as HAMRs (High Area/Mass Ratio objects). I wish I'd known that before coming up with my own term, but I think we're stuck with ETBOs now.
Astrometry:
ZTF00V9 C2018 08 19.31259 22 31 35.41 +00 58 34.9 UNEOCPI41
ZTF00V9 C2018 08 19.31293 22 31 39.87 +00 59 01.2 UNEOCPI41
ZTF00V9 C2018 08 19.35747 22 41 45.04 +01 55 58.5 18.69gUNEOCPI41
ZTF00V9 C2018 08 19.35781 22 41 49.64 +01 56 24.4 18.69gUNEOCPI41
ZTF00V9 C2018 08 19.37902 22 46 47.70 +02 23 14.9 UNEOCPI41
ZTF00V9 C2018 08 19.37936 22 46 52.49 +02 23 39.3 UNEOCPI41
ZTF00Vv C2018 08 21.37456 22 55 51.13 +02 53 10.2 UNEOCPI41
ZTF00Vv C2018 08 21.37491 22 55 56.12 +02 53 35.6 UNEOCPI41
ZTF00Vv C2018 08 21.40331 23 03 00.64 +03 27 26.0 18.87gUNEOCPI41
ZTF00Vv C2018 08 21.40366 23 03 06.06 +03 27 52.2 18.87gUNEOCPI41
ZTF00Vv C2018 08 21.40518 23 03 29.58 +03 29 39.1 18.52gUNEOCPI41
ZTF00Vv C2018 08 21.40553 23 03 34.93 +03 30 05.3 18.52gUNEOCPI41
ZTF00Y5 C2018 09 02.27366 23 33 18.90 +04 03 01.5 x17.32RUNEOCPI41
ZTF00Y5 C2018 09 02.27400 23 33 24.24 +04 03 18.5 x17.32RUNEOCPI41
ZTF00Y5 C2018 09 02.27517 23 33 41.86 +04 04 17.0 x17.09RUNEOCPI41
ZTF00Y5 C2018 09 02.27552 23 33 46.87 +04 04 34.0 x17.09RUNEOCPI41
ZTF00Y5 FC2018 09 02.36535 23 58 01.77 +05 15 25.4 x I41
ZTF00Y5 FC2018 09 02.36569 23 58 08.06 +05 15 42.2 x I41
ZTF00Yq C2018 09 04.30934 23 53 14.51 +04 50 40.8 FixDup x17.83gUNEOCPI41
ZTF00Yq C2018 09 04.30934 23 53 14.51 +04 50 40.8 Duplicat!17.83gUNEOCPI41
ZTF00Yq C2018 09 04.30969 23 53 20.47 +04 50 58.0 x17.83gUNEOCPI41
ZTF00Yq C2018 09 04.35109 00 05 11.80 +05 19 56.1 x17.23RUNEOCPI41
ZTF00Y5 C2018 09 08.23516823 26 16.412+04 51 47.41 17.0 GV J04
ZTF00Y5 C2018 09 08.23524323 26 17.630+04 51 49.99 17.1 GV J04
ZTF00Y5 C2018 09 08.23531523 26 18.770+04 51 52.16 17.1 GV J04
ZTF00Y5 C2018 09 08.23538623 26 19.984+04 51 53.71 17.0 GV J04
ZTF00Y5 C2018 09 08.23545623 26 21.106+04 51 56.08 17.1 GV J04
ZTF00Y5 C2018 09 08.23559723 26 23.414+04 51 59.90 17.1 GV J04
ZTF00Y5 C2018 09 08.23566823 26 24.556+04 52 02.16 17.2 GV J04
ZTF00Y5 C2018 09 08.23573823 26 25.704+04 52 04.69 17.0 GV J04
ZTF00Y5 C2018 09 08.23580823 26 26.843+04 52 06.33 17.1 GV J04
ZTF00Y5 C2018 09 08.23587923 26 28.000+04 52 07.80 17.0 GV J04
ZTF00Y5 C2018 09 08.23594923 26 29.124+04 52 09.68 17.1 GV J04
Station data:
(I41) Palomar Mountain--ZTF (N33.357340 W116.859780) US/California.
Observer A. U. Tomatic. Measurer Q.-Z. Ye.
(J04) ESA Optical Ground Station, Tenerife (N28.300924 W16.511830) Canary
Islands (Spain). Observer D. Abreu. Measurers M. Micheli, D. Koschny, A.
Knöfel, E. Schwab, M. Busch. 1.0-m f/4.4 reflector + CCD.
Orbital elements: ZTF00V9 = ZTF00Vv = ZTF00Y5
Perigee 2018 Sep 7.664998 +/- 0.00838 TT = 15:57:35 (JD 2458369.164998)
Epoch 2018 Sep 8.0 TT; AMR 106.86 +/- 2.68 m2/kg Gray
M 121.438708 +/- 3.0 (J2000 equator)
n 362.501110446 +/- 0.0548 Peri. 220.040294 +/- 0.8
a 42046.57372 +/- 4.24 Node 310.628383 +/- 0.25
e 0.78617234 +/- 0.000769 Incl. 9.900860 +/- 0.14
P1430.04m/0.993d H 33.6 G 0.15 U 10.8
q 8990.720276 +/- 31.5 Q 75102.42718 +/- 39.3
23 of 33 observations 2018 Aug. 19-Sept. 8; mean residual 17".001
Residuals in arcseconds: 180819 I41 16.2- 7.18+ 180821 I41 7.93- 4.19+ 180908 J04 9.47- 3.36- 180819 I41 16.9- 7.29+ 180902 I41( 565+ 83.9+) 180908 J04 7.48- 2.49- 180819 I41 16.8+ 7.60- 180902 I41( 576+ 85.5+) 180908 J04 6.01- 1.96- 180819 I41 14.8+ 7.94- 180902 I41( 602+ 91.1+) 180908 J04 3.22- 2.02- 180819 I41 36.6- 36.8- 180902 I41( 606+ 92.3+) 180908 J04 1.60- 1.25- 180819 I41 38.8- 38.7- 180902 I41(3255+ 548+) 180908 J04 2.39+ .631- 180821 I41 44.3+ 29.5+ 180902 I41(3271+ 552+) 180908 J04 4.09+ .016+ 180821 I41 42.9+ 29.6+ 180904 I41(2208+ 301+) 180908 J04 6.10+ .956+ 180821 I41 .373- 5.68+ 180904 I41(2208+ 301+) 180908 J04 7.97+ 1.01+ 180821 I41 1.13- 6.53+ 180904 I41(2223+ 305+) 180908 J04 9.89+ .865+ 180821 I41 5.67- 3.35+ 180904 I41(3881+ 542+) 180908 J04 11.5+ 1.16+ Ephemerides (geocentric): Date (UTC) HH RA Dec delta elong mag " sig PA ---- -- -- -- ------------- ----------- ------ ----- --- ---- --- 2018 09 08 00 22 33 44.998 +04 39 13.90 69629 166.9 17.8 518 92 2018 09 08 01 22 46 46.183 +05 08 39.86 72131 168.1 17.8 395 93 2018 09 08 02 22 59 03.826 +05 35 26.72 73866 168.4 17.8 319 94 2018 09 08 03 23 10 55.645 +06 00 16.86 74866 168.1 17.9 279 92 2018 09 08 04 23 22 36.352 +06 23 41.76 75147 167.1 17.9 273 89 2018 09 08 05 23 34 19.429 +06 46 06.05 74713 165.5 18.0 299 86 2018 09 08 06 23 46 18.576 +07 07 49.94 73559 163.6 18.0 360 83 2018 09 08 07 23 58 49.208 +07 29 10.81 71663 161.3 18.0 463 81 2018 09 08 08 00 12 10.411 +07 50 24.14 68990 158.6 18.0 620 81 2018 09 08 09 00 26 48.030 +08 11 43.72 65488 155.6 18.0 853 81 2018 09 08 10 00 43 20.212 +08 33 20.39 61079 151.9 18.0 1202 81 2018 09 08 11 01 02 48.683 +08 55 16.86 55649 147.5 17.9 1750 83 2018 09 08 12 01 27 04.961 +09 17 08.92 49026 142.0 17.8 2684 84 2018 09 08 13 02 00 03.138 +09 36 49.88 40944 134.2 17.6 4512 86 2018 09 08 14 02 52 05.289 +09 43 50.76 30957 121.9 17.3 9158 89 2018 09 08 15 04 46 32.234 +08 16 55.94 18376 94.3 17.1 510' 95 2018 09 08 16 13 24 28.001 -09 15 52.15 9441 37.3 19?? 25d 93 2018 09 08 17 18 54 16.185 -04 17 44.16 22480 116.9 16.8 260' 82 2018 09 08 18 20 17 14.835 -00 53 18.90 34213 137.2 17.1 6218 83 2018 09 08 19 21 00 19.389 +00 57 25.35 43566 147.5 17.3 3376 84 2018 09 08 20 21 29 15.034 +02 10 44.95 51176 154.2 17.5 2097 86 2018 09 08 21 21 51 16.395 +03 05 05.22 57420 159.0 17.6 1400 87 2018 09 08 22 22 09 20.786 +03 48 17.35 62533 162.6 17.7 978 89 2018 09 08 23 22 24 57.057 +04 24 20.22 66664 165.3 17.7 707 91 2018 09 09 00 22 38 56.248 +04 55 30.11 69914 167.2 17.8 528 92 2018 09 09 01 22 51 50.901 +05 23 11.74 72354 168.3 17.8 411 93 2018 09 09 02 23 04 03.737 +05 48 21.51 74029 168.6 17.8 340 93 2018 09 09 03 23 15 52.078 +06 11 39.14 74971 168.2 17.9 305 92 2018 09 09 04 23 27 30.420 +06 33 34.02 75194 167.1 17.9 304 89 2018 09 09 05 23 39 12.154 +06 54 28.96 74703 165.6 18.0 335 86 2018 09 09 06 23 51 10.996 +07 14 42.46 73490 163.6 18.0 404 84 2018 09 09 07 00 03 42.500 +07 34 30.04 71533 161.3 18.0 515 82 2018 09 09 08 00 17 06.060 +07 54 04.94 68796 158.6 18.0 682 81 2018 09 09 09 00 31 48.111 +08 13 37.98 65224 155.5 18.0 929 82 2018 09 09 10 00 48 27.931 +08 33 15.59 60737 151.8 17.9 1300 82 2018 09 09 11 01 08 09.562 +08 52 53.12 55217 147.3 17.9 1884 83 2018 09 09 12 01 32 49.838 +09 11 51.92 48487 141.6 17.7 2884 85 2018 09 09 13 02 06 37.570 +09 27 29.63 40268 133.7 17.6 4870 87 2018 09 09 14 03 00 50.723 +09 27 05.14 30093 120.8 17.3 168' 90 2018 09 09 15 05 05 28.965 +07 30 42.61 17262 90.6 17.1 601' 95 2018 09 09 16 14 25 32.801 -09 31 17.30 10082 50.7 18?? 22d 91 2018 09 09 17 19 09 00.102 -03 25 22.47 23542 119.6 16.8 239' 82 2018 09 09 18 20 26 07.444 -00 16 12.90 35071 138.5 17.1 5941 83 2018 09 09 19 21 07 24.721 +01 27 11.98 44273 148.3 17.4 3277 84 2018 09 09 20 21 35 30.984 +02 36 01.00 51766 154.8 17.5 2055 86 2018 09 09 21 21 57 04.558 +03 27 07.10 57916 159.5 17.6 1383 88 2018 09 09 22 22 14 51.387 +04 07 46.22 62947 163.0 17.7 975 90 2018 09 09 23 22 30 15.722 +04 41 40.76 67005 165.7 17.7 712 91 2018 09 10 00 22 44 06.422 +05 10 58.10 70189 167.5 17.8 540 93 2018 09 10 01 22 56 54.882 +05 36 57.62 72567 168.6 17.8 428 93