174P/Echeclus (0174P)

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Type: Periodic Perihelion date: 26 April 2015 Perihelion distance (q): 5.8 Aphelion distance (Q) : 15.6 Period (years): 35.1 Eccentricity (e): 0.46 Inclination (i): 4.3 JPL orbit diagram COBS lightcurve The comet was discovered on 2000 March 3.41 by J. V. Scotti, A. E. Gleason, J. L. Montani, M. T. Read (SPACEWATCH, Steward Observatory, Kitt Peak). They gave the magnitude as 21.0 and noted a stellar appearance. It was reported as a minor planet and received the preliminary minor planet designation "2000 EC98", a centaur in the outer Solar System. This object was later given the name "Echeclus" and was given an official minor planet number of 60558. Y. J. Choi and P. R. Weissman (Jet Propulsion Laboratory, California, USA) observed this object with the 5-m reflector and the Large Format Camera at Palomar Observatory (California, USA) on 30 December 2005. A 600-second R-band exposure revealed a coma extending about 20 arc seconds from the nuclear condensation. The total magnitude was then given as 17.5. Choi obtained a confirming observation on 2006 January 1, while D. Polishook (Wise Observatory) obtained a confirming observation on January 2. The object then received the designation P/2000 EC98, and was later officially designated as periodic comet 174P. 60558 Echeclus is only the second comet (after Chiron) that was named as an asteroid, rather than after the name of its discoverer. Chiron is also a centaur; other centaurs are being observed for signs of a cometary coma. Besides Chiron, three other objects are cross-listed as both comets and asteroids: • 7968 Elst- Pizarro (133P/Elst-Pizarro) • 4015 Wilson-Harrington (107P/Wilson-Harrington) • 118401 LINEAR (176P/LINEAR) On 30 December 2005, when 13.1 AU from the Sun, a large chunk of Echeclus was observed to break off, causing a great cloud of dust. Astronomers have speculated this could have been caused by an impact or by an explosive release of volatile substances. Echeclus appears to have outburst again around June 2011 when it was 8.5 AU from the Sun. On 24 June 2011, follow up imaging with the 2 meter Haleakala-Faulkes Telescope South showed the coma of Echeclus to be very close to the sky background limit. Observations (VEMag = visual equivalent magnitude) Date 10x10 mag Error VEmag Coma ' 19-Mar-14 17.56 0.17 21-Mar-14 17.06 0.08 16.9 0.2 29-Mar-14 17.86 0.14 17.9 0.2 03-Apr-14 17.80 0.12 17.8 0.2 18-Apr-14 17.77 0.17 17.5 0.2 24-Apr-14 17.73 0.10 17.1 0.2 26-Apr-14 17.81 0.08 17.5 0.2 29-Apr-14 17.73 0.09 17.7 0.2 02-May-14 17.60 0.08 17.4 0.2 06-May-14 17.72 0.11 17.7 0.2 14-May-14 17.65 0.06 17.5 0.2 16-May-14 17.46 0.04 17.2 0.2 29-May-14 17.53 0.07 17.4 0.2 05-Jun-14 17.40 0.10 17.4 0.2 09-Jun-14 17.35 0.09 17.3 0.2 19-Jun-14 17.37 0.06 17.3 0.2 25-Jun-14 17.21 0.05 17.1 0.2 28-Jun-14 17.23 0.05 17.2 0.2 02-Jul-14 17.18 0.05 17.1 0.2 10-Jul-14 17.01 0.06 17.0 0.2 17-Jul-14 16.90 0.03 15.4 0.2 25-Jul-14 16.89 0.04 16.9 0.2 28-Jul-14 16.75 0.04 16.7 0.2 30-Jul-14 16.76 0.05 16.7 0.2 03-Aug-14 16.73 0.04 16.6 0.2 07-Aug-14 16.69 0.06 16.6 0.2 14-Aug-14 16.72 0.02 16.6 0.2 20-Aug-14 16.75 0.03 16.5 0.2 22-Aug-14 16.82 0.04 16.6 0.2 24-Aug-14 16.81 0.04 16.0 0.2 26-Aug-14 16.84 0.05 16.2 0.2 30-Aug-14 16.93 0.02 16.4 0.2 01-Sep-14 16.90 0.05 16.5 0.2 11-Sep-14 17.02 0.07 15.6 0.2 13-Sep-14 17.06 0.06 17.0 0.2 17-Sep-14 17.14 0.07 17.1 0.2 21-Sep-14 17.23 0.07 17.2 0.2 27-Sep-14 17.31 0.04 17.3 0.2 29-Sep-14 17.05 0.06 17.0 0.2 08-Oct-14 17.38 0.06 17.4 0.2 15-Oct-14 17.51 0.05 17.5 0.2 17-Oct-14 17.48 0.06 17.5 0.2 19-Oct-14 17.55 0.19 17.4 0.2 21-Oct-14 17.46 0.21 17.4 0.2 23-Oct-14 17.42 0.11 17.4 0.2 25-Oct-14 17.51 0.04 17.5 0.2 27-Oct-14 17.50 0.10 17.5 0.2 07-Nov-14 17.68 0.14 17.6 0.2 12-Nov-14 17.59 0.07 17.5 0.2 16-Nov-14 17.63 0.08 17.6 0.2 21-Nov-14 17.65 0.09 17.6 0.2 25-Nov-14 17.41 0.05 17.1 0.2 01-Dec-14 17.54 0.12 17.1 0.2 03-Dec-14 17.59 0.24 19-Apr-15 17.65 0.11 17.5 0.2 21-Apr-15 17.67 0.18 17.5 0.2 17-May-15 17.64 0.11 17.5 0.2 11-Jun-15 17.37 0.19 15.4 0.2 26-Jun-15 17.36 0.19 16.5 0.2 19-Jul-15 17.24 0.12 16.9 0.2 22-Jul-15 17.27 0.07 17.2 0.2 08-Aug-15 16.89 0.02 16.8 0.2 15-Aug-15 17.06 0.02 16.7 0.2 17-Aug-15 16.99 0.01 16.7 0.2 20-Aug-15 17.08 0.01 17.0 0.2 24-Aug-15 17.04 0.02 16.8 0.2 05-Sep-15 16.69 0.01 16.5 0.2 07-Sep-15 16.79 0.01 16.5 0.2 09-Sep-15 16.54 0.01 16.3 0.2 12-Sep-15 16.53 0.01 16.4 0.2 16-Sep-15 16.62 0.01 16.1 0.2 19-Sep-15 16.63 0.02 16.3 0.2 21-Sep-15 16.69 0.01 16.5 0.2 22-Sep-15 16.68 0.05 16.1 0.2 07-Oct-15 16.93 0.01 16.9 0.2 08-Oct-15 17.04 0.02 16.0 0.2 19-Oct-15 17.18 0.01 17.0 0.2 30-Oct-15 17.39 0.02 17.3 0.2 02-Nov-15 16.77 0.01 16.7 0.2 04-Nov-15 17.40 0.01 17.3 0.2 07-Nov-15 17.38 0.02 17.3 0.2 09-Nov-15 17.39 0.03 17.3 0.2 12-Nov-15 17.50 0.02 17.1 0.2 16-Nov-15 17.46 0.03 15.7 0.2 09-Dec-15 17.82 0.13 17.6 0.2 11-Dec-15 17.73 0.03 17.6 0.2 26-Aug-16 17.72 0.05 n/a n/a 30-Aug-16 15.21 0.01 14.7 0.3 02-Sep-16 15.73 0.01 14.8 0.5 06-Sep-16 16.17 0.02 14.8 0.8 07-Sep-16 16.22 0.01 14.8 0.7 10-Sep-16 16.50 0.01 14.5 0.8 13-Sep-16 16.63 0.02 14.4 0.4 25-Sep-16 16.75 0.04 13.4 0.6 28-Sep-16 16.89 0.01 13.7 0.6 04-Oct-16 16.80 0.02 15.0 0.4 07-Oct-16 17.00 0.01 15.0 0.2 28-Oct-16 17.26 0.10 17.0 0.2 30-Oct-16 17.13 0.00 15.6 0.2 04-Nov-16 17.24 0.01 16.1 0.2 22-Nov-16 17.51 0.05 14.9 0.2 26-Nov-16 17.50 0.03 17.1 0.2 18-Dec-16 17.89 0.04 17.4 0.2 26-Dec-16 17.99 0.16 17.2 0.2 17-Jan-17 18.29 0.06 17.0 0.2 22-Jan-17 18.28 0.07 17.7 0.2 25-Jan-17 18.04 0.06 17.1 0.2 13-Feb-17 18.32 0.12 18.0 0.2 16-Feb-17 18.17 0.10 17.7 0.2 03-Jul-17 18.06 0.11 17.2 0.2 26-Jul-17 18.21 0.03 17.8 0.2 20-Aug-17 18.71 0.13 18.2 0.2 24-Aug-17 18.42 0.12 17.3 0.2 28-Aug-17 18.45 0.08 18.3 0.2 04-Sep-17 18.10 0.04 16-Sep-17 18.01 0.05 17.5 0.2 28-Sep-17 17.81 0.02 17.7 0.2 01-Oct-17 17.87 0.05 17.6 0.2 17-Oct-17 17.79 0.04 17.6 0.2 21-Oct-17 17.86 0.18 16.8 0.2 24-Oct-17 17.87 0.06 17.7 0.2 12-Nov-17 17.69 0.05 17.5 0.2 14-Nov-17 17.55 0.15 17.0 0.3 21-Nov-17 17.48 0.03 17.3 0.2 19-Dec-17 15.70 0.01 12.8 1.2 24-Dec-17 16.34 0.04 13.3 1.7 03-Jan-18 16.98 0.02 14.0 2.0 14-Jan-18 17.39 0.03 14.3 1.5 21-Jan-18 17.60 0.02 14.7 0.8 15-Feb-18 18.22 0.03 14.9 0.5 18-Feb-18 18.15 0.02 15.0 0.7 15-Mar-18 18.21 0.13 16.5 0.5 23-Aug-18 19.31 0.16 19.1 0.2 07-Sep-18 18.84 0.10 18.6 0.2 06-Oct-18 18.62 0.06 18.1 0.2 11-Oct-18 18.30 0.13 18.0 0.2 15-Oct-18 18.57 0.05 18.5 0.2 21-Oct-18 18.67 0.03 18.5 0.2 30-Oct-18 18.43 0.03 18.3 0.2 08-Nov-18 18.59 0.05 18.6 0.2 15-Nov-18 18.31 0.02 18.2 0.2 18-Nov-18 18.43 0.10 18.3 0.2 27-Nov-18 18.47 0.04 18.0 0.2 01-Dec-18 18.55 0.11 18.3 0.2 03-Dec-18 18.49 0.03 18.4 0.2 06-Dec-18 18.34 0.08 18.3 0.2 10-Dec-18 18.54 0.02 18.1 0.2 16-Dec-18 18.55 0.03 17.8 0.2 24-Dec-18 18.56 0.07 18.5 0.2 01-Jan-19 18.64 0.02 18.6 0.2 04-Jan-19 18.79 0.04 18.6 0.2 08-Jan-19 18.79 0.03 18.5 0.2 13-Jan-19 18.79 0.06 18.6 0.2 30-Aug-19 19.73 0.09 18.8 0.2 10-Sep-19 19.25 0.11 18.8 0.2 01-Oct-19 19.38 0.06 19.0 0.2 10-Oct-19 19.29 0.04 19.2 0.2 28-Oct-19 19.08 0.06 n/a n/a 03-Nov-19 19.07 0.05 19.0 0.2 20-Nov-19 19.08 0.07 18.9 0.2 23-Nov-19 19.00 0.04 19.0 0.2 26-Nov-19 18.86 0.05 18.8 0.2 19-Dec-19 18.85 0.04 18.7 0.2 22-Dec-19 19.04 0.05 19.0 0.2 26-Dec-19 18.96 0.14 18.6 0.2 29-Dec-19 19.14 0.07 19.1 0.2 02-Jan-20 19.04 0.05 18.9 0.2 13-Jan-20 19.22 0.05 19.2 0.2 16-Jan-20 19.55 0.05 18.9 0.2 31-Jan-20 19.37 0.04 19.2 0.2 11-Feb-20 19.33 0.08 19.2 0.2 15-Feb-20 19.47 0.19 19.3 0.2 11-Mar-20 19.87 0.11 19.4 0.2 14-Mar-20 19.79 0.18 19.8 0.2 19-Nov-20 18.8 0.4 23-Dec-20 19.5 0.4 30-Oct-22 20.6 0.4