Damocloids are a class of such as 5335 Damocles and 1996 PW that have Halley-type or long-period highly typical of periodic such as Halley's Comet, but without showing a cometary coma or Comet tail. David Jewitt defines a damocloid as an object with a Jupiter Tisserand invariant (TJ) of 2 or less, while Akimasa Nakamura defines this group with the following orbital elements:
However, this definition that does not focus on Jupiter excludes objects such as , , and .
Using the Tisserand's parameter with respect to Jupiter of 2 or less, there are currently 220 damocloid candidates . Of these objects, 189 have orbital greater than 30 days providing reasonably decent orbits. Their average radius is eight kilometers assuming an albedo of 0.04. The albedos of four damocloids have been measured, and they are among the darkest objects known in the Solar System. Damocloids are reddish in color, but not as red as many Kuiper-belt objects or centaurs. Other damocloids include: , , , , and 20461 Dioretsa.
Retrograde objects such as Halley's Comet and damocloid 343158 Marsyas can have relative velocities to Earth of .
Origin
List
this list from the [[JPL SBDB]] contains 20 numbered and 268 unnumbered bodies that meet Akimasa Nakamura's criteria for being classified as a damocloid, that is, either a retrograde orbit, or the following orbital elements: q < 5.2 AU, a > 8.0 AU, and e > 0.75 ''(also see )''. Tisserand's parameter with respect to Jupiter (TJupiter) is also given. Akimasa Nakamura's criteria and a TJupiter of less than two are largely equivalent as only a few listed bodies do not meet the defined TJupiter threshold. Most damocloids are also listed on MPC's list of other unusual minor planets. The orbital data is sourced from JPL-numbered and -unnumbered element files. The list includes A/-designated objects (introduced in 2017) that were mistakenly identified as a comet, but are actually minor planets. However it excludes hyperbolic bodies such as A/2019 G4 as well as 1I/ʻOumuamua and 2I/Borisov, two interstellar objects.
5335 Damocles 11.85 0.866 61.6 CEN — 1.158 1.59 22.11 — 9.37 0.774 35 CEN — 1.948 2.12 16.63 unusual 20461 Dioretsa 23.88 0.901 160.4 CEN −1.534 2.37 45.39 unusual 53.66 0.954 119.3 TNO −0.844 2.46 104.86 unusual 14.23 0.76 3.3 CEN — 2.513 — 3.42 25.04 unusual 8.12 0.562 170.3 CEN −1.397 3.56 12.69 unusual 278.33 0.966 140.7 TNO −2.903 9.42 547.23 — 11.58 0.442 105.1 CEN −0.246 6.47 16.7 — 343158 Marsyas 2.53 0.807 154.4 NEO 1.317 0.49 4.57 — (434620) 2005 VD 6.67 0.251 172.9 CEN −1.394 5 8.34 unusual 10.9 0.401 165.5 CEN −2.090 6.53 15.27 — 191.63 0.954 125.3 TNO −2.069 8.74 374.53 — 471325 Taowu 35.7 0.33 110.2 TNO −1.560 23.9 47.5 — 514107 Kaʻepaokaʻawela 5.13 0.378 163.1 other −0.745 3.19 7.07 — 24.54 0.615 93.6 CEN −0.005 9.45 39.62 — 71.46 0.853 144 TNO −3.061 10.53 132.38 — 54.3 0.798 161.7 TNO −3.601 10.96 97.63 — 42.03 0.497 103.4 TNO −1.021 21.15 62.92 — 246.87 0.954 176 TNO −4.117 11.46 482.29 — 83.6 0.841 137.9 TNO −3.151 13.26 153.94 — 8.17 0.468 151.5 CEN −1.309 4.35 11.99 — 1996 PW 265.49 0.991 30.1 TNO — 1.708 2.49 528.5 unusual — 26.49 0.943 59.4 CEN — 0.960 1.51 51.47 — — 11.24 0.815 23.7 CEN — 2.023 — 2.08 20.41 unusual — 15.13 0.907 42.5 CEN — 1.404 1.41 28.85 — — 17.77 0.948 19.5 NEO — 1.405 0.93 34.62 — — 52.32 0.956 68.2 TNO — 0.790 2.31 102.33 unusual — 10.77 0.793 129.3 CEN −0.627 2.23 19.31 unusual — 23.66 0.9 158.6 CEN −1.510 2.37 44.95 unusual — 90.21 0.963 45.6 TNO — 1.630 3.34 177.07 unusual — 75.23 0.965 17.6 TNO — 1.965 2.62 147.84 unusual — 564.68 0.995 58.5 TNO — 1.069 2.67 1126.68 unusual — 33.1 0.895 18.9 TNO — 2.283 — 3.46 62.74 — — 14.39 0.846 26.8 CEN — 1.946 2.22 26.56 unusual — 33.28 0.849 4.7 TNO — 2.818 — 5.02 61.55 — — 100.43 0.977 165.6 TNO −1.781 2.36 198.5 unusual — 10.45 0.873 4 CEN — 1.879 1.33 19.57 — — 11.56 0.882 9.2 CEN — 1.838 1.37 21.76 — — 11.29 0.831 35.6 CEN — 1.794 1.91 20.67 unusual — 5.87 0.478 130.5 CEN −0.327 3.07 8.67 — 2005 OE 63.24 0.952 67.5 TNO — 0.901 3.05 123.43 unusual — 13.54 0.892 23.2 CEN — 1.727 1.47 25.61 — — 29.41 0.905 91.5 CEN 0.124 2.79 56.03 unusual — 9.16 0.584 110.3 CEN −0.180 3.81 14.51 unusual — 17.78 0.908 14.2 CEN — 1.797 1.64 33.91 — — 838.42 0.995 112.4 TNO −0.948 4.1 1672.73 unusual — 9.6 0.803 165.3 CEN −1.024 1.89 17.31 unusual — 29.57 0.936 9 CEN — 1.829 1.88 57.26 — — 42.12 0.939 150.2 TNO −1.571 2.56 81.68 unusual — 32.19 0.885 172.1 TNO −2.133 3.7 60.67 — — 25.68 0.921 133.5 CEN −0.992 2.04 49.32 unusual — 9.67 0.76 164.7 CEN −1.172 2.32 17.02 unusual — 19.52 0.832 4.2 CEN — 2.409 — 3.28 35.77 unusual — 8.58 0.811 11 CEN — 2.081 — 1.62 15.54 — — 445.81 0.994 76.5 TNO — 0.484 2.66 888.96 unusual — 21.29 0.926 10.6 CEN — 1.747 1.58 41 — — 24.35 0.941 7.2 CEN — 1.664 1.43 47.27 — — 5.44 0.39 108.3 other 0.364 3.32 7.57 — — 30.34 0.914 28.8 TNO — 1.889 2.61 58.07 unusual — 19.35 0.836 17.4 CEN — 2.288 — 3.17 35.53 unusual — 5.69 0.617 96 CEN 0.742 2.18 9.2 — — 14.01 0.878 60.2 CEN — 1.151 1.7 26.31 unusual — 23.54 0.917 69.9 CEN — 0.804 1.95 45.13 unusual — 48.87 0.954 107.4 TNO −0.440 2.23 95.5 — — 11.52 0.855 86.4 CEN — 0.548 1.67 21.37 unusual — 20.04 0.923 22.8 CEN — 1.653 1.55 38.54 — — 12.47 0.833 137.8 CEN −0.852 2.08 22.87 unusual — 13.26 0.902 18 CEN — 1.706 1.3 25.21 — — 31.3 0.955 8.7 TNO — 1.603 1.41 61.2 — — 20.16 0.919 147.8 CEN −1.052 1.63 38.7 — 10.7 0.792 26.2 CEN — 2.057 — 2.22 19.17 — — 378.15 0.984 143.9 TNO −2.454 6.11 750.19 — — 31.72 0.91 146.1 TNO −1.538 2.86 60.57 unusual — 10.96 0.88 8.1 CEN — 1.842 1.32 20.6 — — 31.63 0.952 156.6 TNO −1.215 1.5 61.75 — — 21.61 0.9 41.4 CEN — 1.574 2.16 41.06 — — 10.89 0.827 8.8 CEN — 2.083 — 1.88 19.91 — — 23.07 0.927 18.6 CEN — 1.726 1.69 44.45 — — 2.09 0.093 92 Asteroid belt 2.449 — 1.89 2.28 — — 49.39 0.946 29.2 TNO — 1.844 2.65 96.14 unusual — 62.46 0.941 105.2 TNO −0.533 3.69 121.23 unusual — 173.9 0.969 99.9 TNO −0.462 5.39 342.42 unusual — 14.45 0.897 121.6 CEN −0.414 1.5 27.4 — — 24.22 0.898 16.9 CEN — 2.033 — 2.47 45.96 — — 70.08 0.963 53.4 TNO — 1.262 2.63 137.54 unusual — 14.6 0.762 41.6 CEN — 1.979 3.48 25.72 unusual — 44.84 0.932 18.7 TNO — 2.138 — 3.07 86.62 unusual — 10.02 0.793 15.1 CEN — 2.153 — 2.08 17.96 — — 6.28 0.783 123.8 CEN 0.069 1.36 11.19 — — 2169.28 0.999 64.7 TNO — 0.699 1.72 4336.84 unusual — 14.86 0.805 25.6 CEN — 2.160 — 2.9 26.81 — — 26.98 0.924 143.9 CEN −1.219 2.06 51.89 unusual — 17.29 0.891 15.2 CEN — 1.901 1.89 32.7 — — 26.1 0.918 118.8 CEN −0.657 2.14 50.06 unusual — 28.67 0.903 25.8 CEN — 1.996 2.78 54.56 — 18.82 0.905 27.7 CEN — 1.711 1.79 35.85 — — 13.18 0.78 121.4 CEN −0.643 2.9 23.46 unusual — 22.91 0.939 11.3 CEN — 1.646 1.4 44.41 — — 11.34 0.864 4.5 CEN — 1.940 1.54 21.15 — — 21.06 0.924 3.7 CEN — 1.780 1.6 40.52 — — 15.75 0.4 153.4 CEN −2.522 9.45 22.06 — — 21.26 0.473 100.5 CEN −0.404 11.2 31.33 — — 288.79 0.989 110.4 TNO −0.745 3.12 574.45 unusual — 19.58 0.884 109.3 CEN −0.334 2.28 36.88 unusual — 8.1 0.798 16.2 CEN — 2.087 — 1.64 14.56 — — 8.94 0.78 23.9 CEN — 2.081 — 1.96 15.92 — — 18.56 0.778 24.6 CEN — 2.439 — 4.12 33 unusual — 37.66 0.945 141.6 TNO −1.239 2.06 73.26 unusual — 45.16 0.969 1.2 TNO — 1.582 1.42 88.9 — — 62.79 0.959 146.7 TNO −1.555 2.55 123.03 unusual — 484.17 0.99 70.9 TNO — 0.906 4.89 963.46 unusual — 11.14 0.864 5.3 CEN — 1.934 1.51 20.76 — — 9.58 0.86 5.1 CEN — 1.920 1.34 17.83 — — 13.44 0.884 8 CEN — 1.877 1.56 25.32 — — 29.89 0.882 160 CEN −1.950 3.53 56.26 — — 10.57 0.83 8.5 CEN — 2.066 — 1.8 19.34 — — 6.31 0.478 106.9 CEN 0.262 3.29 9.33 unusual — 9.29 0.588 136.1 CEN −0.996 3.83 14.74 unusual — 59.15 0.974 101.8 TNO −0.225 1.55 116.75 — — 958.56 0.991 98.6 TNO −0.528 8.37 1908.74 — — 10.31 0.848 5.9 CEN — 1.989 1.57 19.05 — — 58.04 0.951 97.1 TNO −0.164 2.82 113.27 unusual — 11.99 0.863 72.9 CEN — 0.883 1.64 22.34 — — 5.68 0.466 175.1 CEN −0.926 3.03 8.33 — — 81.49 0.969 154.7 TNO −1.708 2.54 160.45 unusual — 17.05 0.791 15.4 CEN — 2.442 — 3.57 30.54 unusual — 12.58 0.786 130.4 CEN −0.831 2.69 22.47 unusual — 11.01 0.836 11.3 CEN — 2.039 — 1.81 20.22 — — 19.84 0.92 5.2 CEN — 1.783 1.58 38.1 — — 34.03 0.91 14.3 TNO — 2.206 — 3.06 65 — — 8.17 0.752 61.3 CEN — 1.430 2.03 14.31 unusual — 32.9 0.869 170.8 TNO −2.297 4.31 61.48 — — 12.72 0.886 9.6 CEN — 1.841 1.45 23.99 — — 13.47 0.893 4.4 CEN — 1.831 1.44 25.5 — — 8.99 0.854 6.5 CEN — 1.938 1.31 16.68 — — 13.22 0.894 5.6 CEN — 1.814 1.4 25.03 — — 9.24 0.844 9.5 CEN — 1.971 1.44 17.04 — — 10.38 0.842 6.8 CEN — 2.013 — 1.64 19.12 — — 19.98 0.928 8.8 CEN — 1.708 1.45 38.52 — — 13.16 0.889 9.8 CEN — 1.832 1.46 24.86 — — 7 0.291 95.9 CEN 0.514 4.97 9.04 unusual — 44.84 0.9 92.4 TNO 0.010 4.5 85.18 unusual — 21.37 0.941 93.7 NEO 0.155 1.25 41.48 — — 12.18 0.865 15.8 CEN — 1.903 1.64 22.72 — — 8.26 0.76 18.1 CEN — 2.187 — 1.98 14.53 — — 12.33 0.867 9.1 CEN — 1.937 1.64 23.02 — — 18.81 0.918 3.8 CEN — 1.781 1.54 36.07 — — 28.84 0.903 128.6 CEN −1.078 2.79 54.89 unusual — 12.4 0.889 7.1 CEN — 1.821 1.37 23.43 — — 11.6 0.874 1.5 CEN — 1.898 1.46 21.75 — — 22.47 0.72 169.3 CEN −2.602 6.29 38.64 — — 13.86 0.71 171 CEN −1.895 4.02 23.7 unusual — 9.58 0.756 7.4 CEN — 2.304 — 2.34 16.83 — — 8.37 0.841 9.2 CEN — 1.976 1.33 15.41 — — 71.97 0.955 101.5 TNO −0.368 3.26 140.67 unusual — 21.94 0.835 139.9 CEN −1.491 3.62 40.26 unusual — 12.79 0.875 7.1 CEN — 1.916 1.61 23.97 — — 8.66 0.712 94.4 CEN 0.462 2.49 14.83 unusual — 9.35 0.808 0.3 CEN — 2.136 — 1.8 16.91 — — 16.73 0.877 8.3 CEN — 2.013 — 2.05 31.4 — — 23.96 0.928 7.2 CEN — 1.800 1.72 46.2 — — 456.59 0.989 156.1 TNO −2.506 4.96 908.23 unusual — 11.98 0.886 8.2 CEN — 1.828 1.37 22.58 — — 80.6 0.966 91.7 TNO 0.002 2.76 158.45 unusual — 20.2 0.764 1.6 CEN — 2.797 — 4.76 35.64 unusual — 14.21 0.902 37.9 CEN — 1.492 1.39 27.03 — — 54.15 0.956 91.2 TNO 0.057 2.39 105.91 unusual — 14.52 0.882 14.1 CEN — 1.886 1.72 27.32 — — 8.07 0.836 10.5 CEN — 1.989 1.32 14.82 — — 10.93 0.805 13.4 CEN — 2.150 — 2.13 19.73 — — 144.42 0.965 58 TNO — 1.501 5.05 283.78 unusual — 14.47 0.853 159.2 CEN −1.267 2.13 26.81 unusual — 36.44 0.902 157.5 TNO −1.967 3.57 69.32 unusual — 19.35 0.83 118.2 CEN −0.748 3.28 35.42 unusual — 63.07 0.957 22.2 TNO — 1.945 2.69 123.45 unusual — 29.1 0.936 12.2 CEN — 1.810 1.87 56.32 — — 47.63 0.937 129.7 TNO −1.245 3.01 92.25 unusual — 7.2 0.538 167.1 CEN −1.209 3.32 11.07 unusual — 66.61 0.959 171 TNO −1.922 2.72 130.49 unusual — 10.77 0.875 0.6 CEN — 1.877 1.35 20.19 — — 21.02 0.935 14.1 CEN — 1.633 1.37 40.67 — — 23.25 0.938 11.8 CEN — 1.657 1.44 45.06 — — 13.78 0.918 17.2 NEO — 1.614 1.14 26.42 — — 10.72 0.831 10.5 CEN — 2.054 — 1.81 19.63 — — 13.03 0.66 152.3 CEN −1.706 4.43 21.63 — — 2016 LS 13.34 0.606 114.3 CEN −0.660 5.26 21.42 unusual — 13.9 0.76 21.9 CEN — 2.344 — 3.33 24.46 unusual — 31.02 0.906 105.2 TNO −0.373 2.9 59.13 unusual — 8.54 0.828 4.9 CEN — 2.040 — 1.47 15.61 — 9.2 0.551 92.4 CEN 0.475 4.13 14.27 unusual — 7.39 0.554 138.3 CEN −0.778 3.3 11.49 unusual — 35.69 0.948 87.2 TNO — 0.226 1.85 69.52 — — 3.61 0.526 117.8 Asteroid belt 0.780 1.71 5.51 — — 29.62 0.95 2.3 CEN — 1.662 1.48 57.77 — — 30.39 0.862 11.2 TNO — 2.576 — 4.2 56.59 — — 24.86 0.937 1.4 CEN — 1.741 1.58 48.14 — — 8.47 0.83 2.3 CEN — 2.036 — 1.44 15.5 — — 10.3 0.834 4.6 CEN — 2.051 — 1.7 18.89 — — 11.15 0.85 148.5 CEN −0.847 1.67 20.62 unusual — 14.35 0.882 53 CEN — 1.304 1.69 27 unusual — 10.29 0.81 34.4 CEN — 1.868 1.96 18.63 — — 5.45 0.407 139.8 other −0.474 3.24 7.67 — — 28.69 0.883 137.2 CEN −1.435 3.35 54.03 unusual — 17.57 0.904 19.9 CEN — 1.776 1.69 33.45 — — 186.35 0.984 152.4 TNO −1.852 2.95 369.75 unusual — 24.65 0.946 11.2 CEN — 1.596 1.33 47.97 — — 33.15 0.92 83.4 TNO — 0.383 2.64 63.66 — — 43.25 0.947 74.9 TNO — 0.603 2.29 84.22 unusual — 32.78 0.883 160.9 TNO −2.063 3.82 61.74 unusual — 67.32 0.953 65.8 TNO — 0.974 3.19 131.45 unusual — 1311.87 0.997 55.8 TNO — 1.475 4.46 2619.28 unusual — 14.6 0.622 101.3 CEN −0.156 5.52 23.67 — — 58.9 0.971 94.8 TNO −0.046 1.73 116.07 unusual — 17.38 0.925 71.8 CEN — 0.733 1.31 33.44 — — 34.55 0.857 148.8 TNO −2.121 4.94 64.16 unusual 9.02 0.801 5.1 CEN — 2.147 — 1.79 16.25 — — 11.62 0.782 87.1 CEN — 0.542 2.53 20.71 unusual — 9.66 0.792 113.3 CEN −0.119 2.01 17.3 unusual — 239.43 0.992 152.1 TNO −1.464 1.85 477.02 unusual — 34.08 0.954 2.5 TNO — 1.684 1.56 66.6 — — 125.75 0.975 144.2 TNO −1.729 3.14 248.36 unusual — 30.06 0.747 90.5 CEN 0.147 7.61 52.5 — — 317.81 0.996 108.3 NEO −0.416 1.24 634.38 — — 8.92 0.766 27.9 CEN — 2.072 — 2.09 15.76 unusual — 152.42 0.972 89 TNO — 0.080 4.26 300.57 unusual — 12.93 0.872 63 CEN — 1.105 1.66 24.21 — — 32 0.925 81.3 TNO — 0.446 2.39 61.62 unusual — 95.81 0.983 68.2 TNO — 0.635 1.6 190.02 — — 93.93 0.961 46.9 TNO — 1.672 3.71 184.15 unusual — 370.07 0.99 68.3 TNO — 0.909 3.83 736.31 unusual — 8.95 0.808 1.2 CEN — 2.127 — 1.72 16.19 — — 19.51 0.862 74.1 CEN — 0.804 2.69 36.33 unusual — 154.08 0.981 91 TNO −0.002 2.97 305.19 unusual — 8.15 0.788 170.9 CEN −0.881 1.72 14.57 unusual — A/2018 V3 121.44 0.989 165 TNO −1.339 1.34 241.54 — — 7.25 0.694 152.3 CEN −0.787 2.22 12.27 unusual — (594872) 2019 CR 14.46 0.594 160.3 CEN −2.166 5.87 23.04 — 24.2 0.956 139.6 NEO −0.754 1.08 47.32 — — A/2019 G2 699.85 0.997 159.2 TNO −1.746 2.29 1397.41 — — A/2019 G3 17.15 0.834 156.8 CEN −1.540 2.85 31.45 — — 8.79 0.555 134.3 CEN −0.918 3.91 13.66 unusual — 11.67 0.702 108.3 CEN −0.224 3.48 19.86 unusual — 12.42 0.765 14.8 CEN — 2.342 — 2.91 21.93 — — A/2019 O2 57.37 0.831 93.3 TNO −0.121 9.68 105.05 — — A/2019 O4 32.88 0.889 115.1 TNO −0.817 3.64 62.12 — — 25.11 0.92 113 CEN −0.465 2.01 48.22 unusual — A/2019 Q2 59.68 0.979 159 NEO −1.205 1.26 118.11 — — A/2019 T1 38.24 0.888 120.9 TNO −1.143 4.28 72.2 — — 37.39 0.931 22 TNO — 1.948 2.56 72.22 unusual — A/2020 A1 25.94 0.936 149 CEN −1.152 1.67 50.2 — — A/2020 B1 52.32 0.967 18.5 TNO — 1.641 1.75 102.88 — — 7.69 0.922 165.5 NEO −0.237 0.6 14.79 — — 2020 EP 10.5 0.764 76.4 CEN — 0.927 2.48 18.51 unusual — 14.4 0.773 28.6 CEN — 2.216 — 3.27 25.52 unusual — A/2020 H9 341.71 0.992 137.9 TNO −1.458 2.58 680.84 — — 16.6 0.709 147.3 CEN −1.808 4.84 28.36 unusual — 13.07 0.872 38.7 CEN — 1.612 1.68 24.47 unusual — 7.94 0.502 106.1 CEN 0.061 3.95 11.94 unusual — 34.88 0.88 103.8 TNO −0.440 4.2 65.57 unusual — 56.08 0.955 82.5 TNO — 0.349 2.54 109.62 unusual — A/2020 M4 5092.51 0.999 160.1 TNO −2.843 5.95 10179.07 — — 6.24 0.376 166.6 CEN −1.139 3.89 8.58 unusual — 6.9 0.684 155.8 CEN −0.779 2.18 11.63 unusual — 28.37 0.894 79.5 CEN — 0.565 3 53.75 unusual — 674.79 0.993 76.8 TNO — 0.627 4.82 1344.75 unusual — 19.13 0.875 80.5 CEN — 0.579 2.39 35.88 — — 18.18 0.856 77.4 CEN — 0.709 2.62 33.74 unusual — 17.52 0.884 5.7 CEN — 2.003 — 2.03 33.02 unusual — 20.44 0.878 105.6 CEN −0.254 2.49 38.4 unusual — 7.73 0.773 161.2 CEN −0.791 1.75 13.71 unusual — 23.54 0.918 32.5 CEN — 1.647 1.94 45.14 — — 501.83 0.967 169.3 TNO −4.896 16.49 987.16 — — 7.6 0.435 160.4 CEN −1.366 4.29 10.91 unusual — 35.41 0.889 148.6 TNO −1.892 3.93 66.88 unusual — 22.12 0.82 10.8 CEN — 2.555 — 3.99 40.25 unusual — A/2021 E2 216.27 0.989 167.5 TNO −1.802 2.29 430.26 — — A/2021 E4 733.1 0.994 116.4 TNO −1.181 4.68 1461.53 — — 10.81 0.792 54.9 CEN — 1.492 2.24 19.37 — — 86.21 0.96 125.1 TNO −1.252 3.46 168.96 unusual — 24.64 0.944 2.3 CEN — 1.652 1.39 47.89 — — 25.64 0.869 129 CEN −1.179 3.36 47.92 — — 8.412 0.5885 63.78 CEN — 1.53 3.461 13.36 unusual — 6.322 0.6159 71.35 CEN — 1.38 2.428 10.22 unusual — 321.1 0.9859 84.79 TNO — 0.255 4.524 637.62 unusual — 105.8 0.9619 103.18 TNO −0.513 4.025 207.49 unusual —
See also
Notes
External links
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