Tuesday, July 25, 2017

New Comet: C/2017 O1

CBET nr. 4414, issued on 2017, July 24, announces the discovery of a comet (magnitude ~15.3) in the course of the "All-Sky Automated Survey for Supernovae" (ASASSN) program, from images taken with the 14-cm "Cassius" survey telescope at Cerro Tololo on July 19.32 UT. The new comet has been designated C/2017 O1. 

I performed follow-up measurements of this object, while it was still on the neocp. Stacking of 10 unfiltered exposures, 60 seconds each, obtained remotely on 2017, July 23.7 from Q62 (iTelescope network) through 0.50-m f/6.8 astrograph + CCD + f/4.5 focal reducer, shows that this object is a comet with a sharp central condensation surrounded by diffuse coma about 3 arcmins in diameter

My confirmation image (click on it for a bigger version)

Below you can see the discovery image by ASASSN survey

Credit: ASASSN

M.P.E.C. 2017-O45 assigns the following preliminary parabolic orbital elements to comet C/2017 O1: T 2017 Oct. 14.3; e= 1.0; Peri. =  20.29; q = 1.51;  Incl.= 39.75

Below you can see a graph generated using the software Orbitas and showing the predicted magnitude for this comet (click on the image for a bigger version). Visual estimates have the comet at mag. ~10 on July 24, 2017. Syuichi Nakano, Sumoto, Japan, notes on CBET 4414 that this comet could reach total visual magnitude 7 during September-November. A word of caution: as always with comets, the future magnitudes reported here are only indicative.

UPDATE - August 26, 2017

According to CBET 4426: "After considerable discussion, the IAU "Working Group for Small Body Nomenclature" (formerly the IAU "Committee for Small Body Nomenclature" and the IAU "Small Bodies Names Committee") has decided to accept the name "ASASSN" for comet C/2017 O1 (cf. CBET 4414)."

by Ernesto Guido