Electronic Telegram No. 5622
Central Bureau for Astronomical Telegrams
Mailing address:  Hoffman Lab 209; Harvard University;
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Prepared using the Tamkin Foundation Computer Network


COMET 240P/NEAT
     Vivian Carvajal, Catalina Sky Survey, reports that CCD images obtained
with the 2.25-m Bok reflector at Kitt Peak on Oct. 3.5 UT show a companion
object (now denoted 'component B') at mag 19.2-19.3 moving at the same rate
as the main comet ('component A', at mag 15.0-15.2).  Component B was then
located 74" west and 53" south of component A.  Astrometry for component B
appears on MPEC 2025-T124, dating back to June 4, when observations by M.
Jaeger and G. Rhemann with a 0.30-m reflector at Tivoli, Namibia, showed the
fragment at mag 18.8-19.1.  CCD observations by J.-C. Merlin using a 0.51-m
f/4.5 reflector at Siding Spring on Sept. 7.7 showed component B as bright as
mag 18.0-18.4.  A. Hale, Cloudcroft, NM, USA, reported mag 18.4-18.8 for
component B from CCD images obtained remotely on Sept. 17.2 with a 0.35-m f/3
Cassegrain reflector at Cerro Tololo.  The pre-October observations of
component B were evidently all identified after Carvajal's report became
known, as the fragment appears quite faint on most of these images.  On Sept.
29.79, CMOS imaging by K. Yoshimoto (Yamaguchi, Japan) with a 0.30-m f/4
reflector shows component B at mag 18.7 with an apparent faint tail 1'.7 long
in p.a. 284 degrees (photo posted on "ICQ Comet Observations" Facebook forum).
T. Prystavski (Lviv, Ukraine) also has posted a photo on the ICQ forum taken
on Oct. 3.75 UT with an iTelescope 0.43-m f/6.8 astrograph at Siding Spring
that shows component B at total mag about 18.5 with a tail 0'.2 long in p.a.
273 degrees; component A had total mag 13.3 with coma diameter 1'.1 and a tail
about 8'.7 long in p.a. 259 degrees.
     CCD total magnitudes for component A:  June 29.82 UT, 14.9 (H. Sato,
Tokyo, Japan; remotely using a 0.51-m astrograph at Siding Spring; 15" coma
with a 3'.6 tail toward p.a. 230 degrees); July 7.40, 13.8 (T. Prystavski,
Lviv, Ukraine; remotely using a 0.51-m reflector located at Rio Hurtado,
Chile); July 20.73, 14.2 (K. Kadota, Ageo, Japan, 0.25-m f/5.0 reflector);
Aug. 4.80, 14.0 (Prystavski; 0.51-m reflector at Siding Spring); Aug. 23.75,
13.9 (Kadota); Sept. 3.78, 13.5 (Prystavski); Sept. 7.70, 13.4 (Kadota).
     Visual total-magnitude and coma-diameter estimates for component A:
Aug. 28.33 UT, 13.4, 1' (J. G. de S, Aguiar, Campinas, Brazil, 0.30-m
reflector); 31.32, 13.2, 1' (Aguiar); Sept. 1.12, 12.8, 1'.5 (J. J. Gonzalez,
Leon, Spain, 0.20-m reflector); 3.32, 13.2, 1' (Aguiar); 18.09, 12.9, 0'.5 (W.
Hasubick, Buchloe, Germany, 0.44-m reflector); 21.80, 14.2, 0'.5 (S. Yoshida,
Gunma, Japan, 0.40-m reflector).


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

                         (C) Copyright 2025 CBAT
2025 October 13                  (CBET 5622)              Daniel W. E. Green