Comets - C/2018 U1 (Lemmon) - CK18U010
Type Hyperbolic Perihelion Date 1 November 2021 Perihelion Distance (q) 5.0 Aphelion Distance (Q) n/a Period (Years)   n/a Eccentricity (e)   1.00 Inclination (i)   108.3 Click for NASA orbit diagram
Hills Observatory: 1 January 2013 to 13 October 2019
An apparently asteroidal object of 20th magnitude was found in Mt Lemmon Survey images taken with the 1.5m reflector on 27 October 2018. It was placed on the PCCP as ZU8D586 and follow up observations showed that it was slightly diffuse.  Gareth Williams notes on the MPEC: This object was reported as a new NEO and was moved to the PCCP when the orbit looked cometary. Early reports from some observers using small telescopes implied that the object was, in fact, a comet, but these reports were not confirmed at the time by observers using large telescopes. Responding to a query from the MPC, W. Ryan (H01, 2.4-m reflector) remarked that his 27 October images showed a subtle cometary appearance, and that the 19 November images had a PSF ~ 1.5 times that of field stars and a slightly elongated coma or tail in P.A. 35. Date 10x10 mag Error Kphot mag Coma ' 08-Jun-19   18.57   0.04 18.4 0.2 25-Jun-19   18.61   0.15 18.6 0.2 08-Aug-19   18.43   0.07 18.4 0.2 27-Aug-19   18.27   0.02 18.0 0.2 03-Sep-19   18.28          0,04 17.4 0.3 18-Sep-19   18.26   0.06 18.1 0.2 30-Sep-19   18.22   0.11 18.0 0.2