MPEC 2017-U181: COMET C/2017 U1 (PANSTARRS)
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M.P.E.C. 2017-U181 Issued 2017 Oct. 25, 03:53 UT The Minor Planet Electronic Circulars contain information on unusual minor planets and routine data on comets. They are published on behalf of Division F of the International Astronomical Union by the Minor Planet Center, Smithsonian Astrophysical Observatory, Cambridge, MA 02138, U.S.A. Prepared using the Tamkin Foundation Computer Network MPC@CFA.HARVARD.EDU URL https://www.minorplanetcenter.net/ ISSN 1523-6714 COMET C/2017 U1 (PANSTARRS) Further observations of this object are very much desired. Unless there are serious problems with much of the astrometry listed below, strongly hyperbolic orbits are the only viable solutions. Although it is probably not too sensible to compute meaningful original and future barycentric orbits, given the very short arc of observations, the orbit below has e ~ 1.2 for both values. If further observations confirm the unusual nature of this orbit, this object may be the first clear case of an interstellar comet. Observations: CK17U010 C2017 10 18.47298 01 59 57.442+02 06 04.30 19.8 TLEU181F51 CK17U010 C2017 10 18.49990 01 59 08.910+02 07 20.19 LEU181F51 CK17U010 C2017 10 19.39715 01 34 55.362+02 45 03.20 19.9 TLEU181F51 CK17U010 C2017 10 19.40837 01 34 38.745+02 45 28.24 19.9 TLEU181F51 CK17U010 C2017 10 19.41968 01 34 21.948+02 45 53.55 20.1 TLEU181F51 CK17U010 C2017 10 19.43106 01 34 05.174+02 46 18.89 20.1 TLEU181F51 CK17U010 KC2017 10 19.86072 01 24 07.89 +03 01 07.5 19.6 TUEU181104 CK17U010 KC2017 10 19.86492 01 24 02.21 +03 01 16.3 19.8 TUEU181104 CK17U010 KC2017 10 19.86905 01 23 56.69 +03 01 24.7 20.3 TUEU181104 CK17U010 KC2017 10 19.94093401 22 22.288+03 03 53.76 20.3 TUEU181J04 CK17U010 KC2017 10 19.94390101 22 18.372+03 03 59.57 20.1 TUEU181J04 CK17U010 C2017 10 20.17250 01 17 27.47 +03 11 07.8 19.9 TUEU181I52 CK17U010 C2017 10 20.17348 01 17 26.22 +03 11 09.6 20.2 TUEU181I52 CK17U010 C2017 10 20.17448 01 17 24.96 +03 11 11.3 20.2 TUEU181I52 CK17U010 C2017 10 20.17546 01 17 23.73 +03 11 13.0 20.6 TUEU181I52 CK17U010 KC2017 10 21.22371 00 57 56.30 +03 39 16.9 20.2 ToEU181291 CK17U010 KC2017 10 21.22623 00 57 53.76 +03 39 20.5 19.5 ToEU181291 CK17U010 KC2017 10 21.22877 00 57 51.19 +03 39 24.2 19.6 ToEU181291 CK17U010 C2017 10 21.37476 00 55 26.71 +03 42 45.0 20.4 ToEU181926 CK17U010 C2017 10 21.37804 00 55 23.53 +03 42 49.8 20.1 ToEU181926 CK17U010 C2017 10 21.38132 00 55 20.35 +03 42 53.7 20.4 ToEU181926 CK17U010 |C2017 10 22.29708 00 41 56.27 +04 01 25.0 vEU181H06 CK17U010 |C2017 10 22.30118 00 41 52.93 +04 01 29.3 vEU181H06 CK17U010 |C2017 10 22.30512 00 41 49.76 +04 01 33.5 20.7 TvEU181H06 CK17U010 1C2017 10 22.46548 00 39 44.84 +04 04 55.4 EU181Q62 CK17U010 1C2017 10 22.47027 00 39 41.16 +04 04 59.9 EU181Q62 CK17U010 1C2017 10 22.47506 00 39 37.39 +04 05 04.8 19.9 T EU181Q62 CK17U010 KC2017 10 23.18830 00 31 01.55 +04 16 02.6 20.4 TqEU181734 CK17U010 KC2017 10 23.19547 00 30 56.65 +04 16 08.7 20.1 TqEU181734 CK17U010 KC2017 10 23.20264 00 30 51.76 +04 16 14.6 20.4 TqEU181734 CK17U010 C2017 10 24.23395 00 20 19.64 +04 30 08.4 20.9 TUEU181G96 CK17U010 C2017 10 24.23917 00 20 16.75 +04 30 12.3 UEU181G96 CK17U010 C2017 10 24.24438 00 20 13.82 +04 30 15.6 21.0 TUEU181G96 CK17U010 C2017 10 24.24957 00 20 10.85 +04 30 19.7 20.7 TUEU181G96 Observer details: 104 San Marcello Pistoiese. Observers P. Bacci, M. Maestripieri. Measurers P. Bacci, L. Tesi, G. Fagioli. 0.60-m f/4 reflector + CCD. 291 LPL/Spacewatch II. Observer R. A. Mastaler. 1.8-m f/2.7 reflector + CCD. 734 Farpoint Observatory. Observer G. Hug. 0.69-m reflector + CCD. 926 Tenagra II Observatory. Observers M. Schwartz, P. R. Holvorcem. Measurer M. Schwartz. 0.81-m f/7 Ritchey-Chretien + CCD. F51 Pan-STARRS 1, Haleakala. Observers J. Bulger, T. Lowe, A. Schultz, M. Willman. Measurers K. Chambers, S. Chastel, L. Denneau, H. Flewelling, M. Huber, E. Lilly, E. Magnier, R. Wainscoat, C. Waters, R. Weryk. 1.8-m Ritchey-Chretien + CCD. G96 Mt. Lemmon Survey. Observer G. J. Leonard. Measurers E. J. Christensen, D. C. Fuls, A. R. Gibbs, A. D. Grauer, J. A. Johnson, R. A. Kowalski, S. M. Larson, G. J. Leonard, R. G. Matheny, R. L. Seaman, F. C. Shelly. 1.5-m reflector + 10K CCD. H06 iTelescope Observatory, Mayhill. Observer H. Sato. 0.43-m f/6.8 astrograph + CCD + f/4.5 focal reducer. I52 Steward Observatory, Mt. Lemmon Station. Observer R. A. Kowalski. Measurers E. J. Christensen, D. C. Fuls, A. R. Gibbs, A. D. Grauer, J. A. Johnson, R. A. Kowalski, S. M. Larson, G. J. Leonard, R. G. Matheny, R. L. Seaman, F. C. Shelly. 1.0-m reflector + CCD. J04 ESA Optical Ground Station, Tenerife. Observer D. Abreu. Measurers M. Micheli, D. Koschny, M. Busch, A. Knoefel, E. Schwab. 1.0-m f/4.4 reflector + CCD. Q62 iTelescope Observatory, Siding Spring. Observer H. Sato. 0.51-m f/6.8 astrograph + CCD + f/4.5 focal reducer. Orbital elements: C/2017 U1 (PANSTARRS) Epoch 2017 Sept. 4.0 TT = JDT 2458000.5 T 2017 Sept. 9.41719 TT MPCW q 0.2515404 (2000.0) P Q z -0.7541603 Peri. 241.01670 -0.63536548 +0.68733697 +/-0.0181483 Node 24.61531 +0.49903801 +0.71329677 e 1.1897018 Incl. 122.32770 -0.58929769 -0.13702411 From 34 observations 2017 Oct. 18-24, mean residual 0".5. Ephemeris: C/2017 U1 (PANSTARRS) Date TT R. A. (2000) Decl. Delta r Elong. Phase m1 m2 2017 09 25 09 48 43.3 -06 12 59 0.6925 0.5884 34.9 102.8 20.5 ... 2017 10 10 07 36 11.4 -05 42 56 0.2294 0.9879 80.7 86.0 18.8 ... 2017 10 18 02 14 50.4 +01 42 29 0.1968 1.1887 166.6 11.2 18.7 ... 2017 10 24 00 22 33.4 +04 27 26 0.3622 1.3344 156.3 17.4 20.2 2017 10 25 00 13 40.3 +04 38 57 0.3943 1.3583 153.3 19.2 20.4 2017 10 26 00 06 10.5 +04 48 35 0.4270 1.3821 150.6 20.7 20.6 ... 2017 11 01 23 38 46.8 +05 25 33 0.6318 1.5233 138.3 25.7 21.6 ... 2017 11 09 23 23 45.8 +05 54 48 0.9168 1.7069 127.0 27.6 22.5 ... 2017 11 24 23 16 52.8 +06 41 38 1.4693 2.0399 110.7 26.9 23.8 Gareth V. Williams (C) Copyright 2017 MPC M.P.E.C. 2017-U181


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