CBET 4775 & MPEC 2020-J68, issued on 2020, May 14, announce that an apparently asteroidal object discovered on images taken at Palomar on 2019 June 4 and 7 with the 1.2-m f/2.4 Schmidt telescope (and given the minor-planet designation 2019 LM_4 when published on MPS 1001527, along with observations made elsewhere on June 8) has been re-discovered showing cometary appearance at two other observatories. The new comet has been designated P/2019 LM4 (Palomar).

According to the CBET 4775: B. Li reported the discovery by G. Zhaori of an extended object on images taken by L. F. Hu with the 1.04-m f/1.8 Schmidt telescope at the XuYi Station of Purple Mountain Observatory on May 11 UT in the course of the "Chinese Near Earth Object Survey" (discovery observations tabulated below). Before the object was posted on the Minor Planet Center's NEOCP webpage, it wasdiscovered independently in images obtained with the Pan-STARRS1 1.8-m Ritchey-Chretien reflector at Haleakala on May 12, with Y. Ramanjooloo (University of Hawaii) reporting that the full-width-at-half-maximum size was 3".6 compared to 1".2 for nearby stars. Observations were subsequently identified at the Minor Planet of yet another apparent independent discovery of the comet from 2020 May 9.5 at mag 16.4-17.0 with a 0.5-m f/2 Schmidt reflector at Haleakala, Hawaii, in the course of the "Asteroid Terrestrial- Impact Last Alert System" (ATLAS) search program, though it appears that the ATLAS team did not report it as a comet.

Comet P/2019 LM4Palomar
© Remanzacco Blogspot

Comet P/2019 LM4 Palomar
© Remanzacco Blogspot
We performed follow-up measurements of this object while it was still on the PCCP webpage.

Stacking of 14 unfiltered exposures, 120 seconds each, obtained remotely on 2020, May 13.2 from X02 (Telescope Live, Chile) through a 0.6-m f/6.5 astrograph + CCD, shows that this object is a comet with a compact round coma about 15" in diameter (Observers E. Guido, M. Rocchetto, E. Bryssinck, M. Fulle, G. Milani, C. Nassef, G. Savini).

Stacking of 16 unfiltered exposures, 60 seconds each, obtained remotely on 2020, May 13.4 from H06 (iTelescope, New Mexico) through a 0.50-m f/4.5 astrograph + CCD, shows that this object is a comet with a compact coma about 12" in diameter (Observers A. Valvasori & E. Guido).

MPEC 2020-J68, assigns the following elliptical elements to comet P/2019 LM4 (Palomar): T 2019 June 18.24; e= 0.58; Peri. = 68.37; q = 2.37; Incl.= 36.39