Electronic Telegram No. 5669
Central Bureau for Astronomical Telegrams
Mailing address:  Hoffman Lab 209; Harvard University;
 20 Oxford St.; Cambridge, MA  02138; U.S.A.
e-mail:  cbatiau@eps.harvard.edu (alternate cbat@iau.org)
URL http://www.cbat.eps.harvard.edu/index.html
Prepared using the Tamkin Foundation Computer Network


COMET C/2024 E1 (WIERZCHOS)
     Q.-Z. Ye and M. S. P. Kelley, University of Maryland, College Park, on 
behalf of the Zwicky Transient Facility (ZTF) Solar System Working Group;
Q. Zhang, Lowell Observatory; and C. Schmidt, Boston University, report an 
apparent disruption of comet C/2024 E1 based on images obtained with the 4.3-m 
Lowell Discovery Telescope (LDT) and by the ZTF survey using the Oschin 1.2-m 
Schmidt telescope at Palomar Observatory.  The comet first showed a lack of 
clear central condensation in LDT images taken on 2026 Mar. 12.15 UT (see
website URL https://pages.astro.umd.edu/~qye/shared/2024E1_LDT_20260312.png).
A review of observations from the ZTF Twilight Survey beginning on 2026 Feb.
25 showed a brief brightening of -0.19 mag between Feb. 28 and Mar. 6, 
followed by a rapid decline in brightness.  The fading became more pronounced
after Mar. 6, reaching a rate of about 0.2-0.3 mag/day (approximately r^-12
to r^-19, as a function of heliocentric distance).  The comet's apparent 
r-band magnitude was measured as follows:  Feb. 25.12, 12.89 +/- 0.06; Feb. 
28.12, 13.54 +/- 0.03; Mar. 3.12, 13.35 +/- 0.04; Mar. 6.12, 13.48 +/- 0.04; 
Mar. 9.12, 14.23 +/- 0.04; Mar. 12.12, 15.06 +/- 0.02; Mar. 14.12, 15.51 +/- 
0.20.  All photometry was measured in a 5"-radius aperture and in the PS1 
photometric system.
     Selected visual total-magnitude and coma-diameter estimates:  2025 Sept. 
14.86 UT, 13.5, 1'.2 (J. J. Gonzalez Suarez, Leon, Spain, 0.20-m reflector);
2026 Jan. 25.93, 6.3, 3' (J. G. de S. Aguiar, Campinas, Brazil, 11x80 
binoculars); Feb. 6.98, 6.9, 6' (M. Goiato, Aracatuba, Brazil, 7x50 
binoculars); 15.96, 7.0, 2' (W. Souza, Atibaia, Brazil, 10x42 binoculars);
19.81, 7.5, 6' (Gonzalez, 20x80 binoculars); Mar. 1.73, 8.3, 3'.4 (V. Gonano, 
Udine, Italy, 20x80 binoculars); 6.96, 9.1, 4' (Gonano); 9.75, 9.6, 4' 
(Gonano); 12.86, 9.5, 5' (Gonzalez, 25x100 binoculars); 15.91, 10.4, 1' 
(Aguiar, 0.30-m reflector); 16.85, 9.8, 5' (Gonzalez, 0.10-m reflector).
Images of the comet taken in February when it was near its brightest, as
posted on the "ICQ Comet Observations" forum on Facebook, show a thin ion
tail at least 3 degrees long and as many as three distinct dust tails
spanning some 90 degrees in position angle.


NOTE: These 'Central Bureau Electronic Telegrams' are sometimes
      superseded by text appearing later in the printed IAU Circulars.

                         (C) Copyright 2026 CBAT
2026 March 17                    (CBET 5669)              Daniel W. E. Green