Comet C/2018 R5 (Lemmon)
Abstract
An apparently asteroidal object found on CCD survey images obtained by A. D. Grauer with the Mount Lemmon 1.5-m reflector on Sept. 8.2 UT (discovery observations tabulated below) has been found to show cometary appearance by CCD astrometrists elsewhere, following posting on the Minor Planet Center's PCCP and NEOCP webpages. 2018 UT R.A. (2000) Decl. Mag. Observer Sept. 8.23378 23 11 51.30 +30 41 27.3 19.0 Grauer 8.23896 23 11 50.87 +30 41 22.8 19.1 " 8.24414 23 11 50.51 +30 41 16.2 " 8.24933 23 11 50.12 +30 41 10.1 19.3 " H. Sato, Tokyo, Japan, reports that twelve stacked 60-s exposures taken on Sept. 9.5 UT with an iTelescope 0.61-m f/6.5 astrograph at the Sierra Remote Observatory near Auberry, CA, USA, shows a strongly condensed coma 8" in diameter (full-width-at-half-maximum 4".4, vs. 2".9 for a nearby star) and no obvious tail; the total magnitude was 19.6 as measured within a circular aperture of radius 5".0. E. J. Christensen writes that four 60-s exposures taken in good conditions on Sept. 13.17 UT with the Steward Observatory 1.0-m reflector at Mt. Lemmon show a 10" coma that was slightly extended toward the north (magnitude 18.7-19.0). K. Sarneczky and R. Szakats, Konkoly Observatory, find that four stacked 120-s unfiltered images taken with the 0.60-m Schmidt telescope at Piszkesteto, Hungary, on Sept. 15.9 show the object to appear softer than nearby stars of similar brightness (FWHM about 4".0 in 3".0 seeing).
- Publication:
-
Central Bureau Electronic Telegrams
- Pub Date:
- September 2018
- Bibcode:
- 2018CBET.4559....1G