240P/NEAT (0240P)

Type: Periodic Perihelion date: 19 December 2025 Perihelion distance (q): 2.1 Aphelion distance (Q) : 5.6 Period (years): 7.6 Eccentricity (e): 0.45 Inclination (i): 23.5 JPL orbit diagram COBS lightcurve Atlas K. J. Lawrence reported the discovery of a comet of magnitude 18.4 by the NEAT team from CCD images taken with the 1.2-m Schmidt telescope at Palomar on 7 December 2002. The comet was independently recovered between 9 and 11 August 2010 by H. Taylor (Rayle, GA, U.S.A., 25-cm reflector), by H. Sato (Tokyo, Japan; remotely, 25-cm reflector, RAS Observatory, Mayhill, NM, U.S.A.; 20" coma and 30" tail in p.a. 260 deg), by L. Elenin (Lyubertsy, Russia; remotely, 45-cm f/2.8 astrograph, ISON-NM Observatory, Mayhill; 50" tail), and by T. Yusa (telescope data same as for Sato; faint 25" tail in p.a. 252 deg). In 2007 the comet's orbit was perturbed by Jupiter during a 0.25 au approach with reduced the perihelion distance from 2.53 to 2.12 au. In response to this the comet appears to have undergone periods of sustained increased activity. A faint fragment of the comet (mag 18-19), which was designated B, was reported at the 2025 return, with observations from 4 June onwards. Observations (VEMag = visual equivalent magnitude) Date 10x10 mag Error VEmag Coma ' 240P 11-Oct-17 15.74 0.04 14.0 0.7 11-Oct-17 15.74 0.04 13.6 1.0 25-Oct-17 15.92 0.01 13.6 0.8 20-Nov-17 16.11 0.02 12.8 0.9 01-Jan-18 16.36 0.02 13.4 0.8 11-Feb-18 16.16 0.05 13.4 1.2 13-Oct-18 17.55 0.09 16.0 0.4 10-Nov-18 16.91 0.09 15.8 0.4 23-Nov-18 15.72 0.02 14.8 0.6 03-Dec-18 15.92 0.02 14.7 0.7 14-Dec-18 16.13 0.02 14.6 0.7 31-Dec-18 16.06 0.01 14.8 0.7 01-Jan-19 16.00 0.02 14.1 0.7 12-Jan-19 16.18 0.01 14.6 0.8 07-May-19 17.88 0.02 16.0 0.5 27-May-19 18.15 0.11 15.4 0.4 22-Aug-25 15.3 0.4 27-Sep-25 15.0 0.3 29-Nov-25 11.9 3.0 08-Dec-25 12.6 2.7 20-Dec-25 12.5 2.5 13-Jan-26 14.5 0.7 09-Feb-26 15.2 0.6 240P-B 29-Nov-25 14.4 0.7 08-Dec-25 13.7 1.2 20-Dec-25 12.8 3.3 13-Jan-26 15.7 0.7 09-Feb-26 16.7 0.5