[Iaude] CBET 5389: COMET 13P/OLBERS

[quai at eps.harvard.edu]

                                                  Electronic Telegram No. 5389
Central Bureau for Astronomical Telegrams
Mailing address:  Hoffman Lab 209; Harvard University;
 20 Oxford St.; Cambridge, MA  02138; U.S.A.
e-mail:  cbatiau at eps.harvard.edu (alternate cbat at iau.org)
URL http://www.cbat.eps.harvard.edu/index.html
Prepared using the Tamkin Foundation Computer Network


COMET 13P/OLBERS
     Hidetaka Sato (Bunkyo-ku, Tokyo, Japan) found that comet 13P had a
strongly condensed coma 8" in diameter in CCD exposures taken on 2023 Oct.
14.76 UT with a 0.51-m f/6.8 astrograph at Siding Spring, NSW; the magnitude
was 19.5 as measured within a circular aperture of radius 4".3.  On 2023
Dec. 3.11, using a "Deep Sky Chile" 0.51-m f/6.8 astrograph at Rio Hurtado,
Chile, Sato found a strongly condensed coma 25" in diameter with a faint tail
1'.8 long toward p.a. about 0 degrees; the magnitude was 16.6 as measured
within a circular aperture of radius 13".0.
     Hirohisa Sato reports the following total CCD magnitudes from images of
comet 13P taken by T. Ikemura at Shinshiro, Japan:  2024 Jan. 14.48 UT, 15.3
(strongly condensed coma about 0'.9 in diameter, with a tail about 1'.0 long
toward p.a. about 67 degrees in twenty-five stacked 60-s exposures); Feb.
12.47, 12.8 (strongly condensed inner coma about 2'.2 in diameter and a faint
outer coma about 9'.9 in diameter in twenty-seven stacked 60-s exposures);
Mar. 2.49, 12.4 (strongly condensed inner coma about 2'.3 in diameter and a
faint outer coma about 10'.1 in diameter, on twenty-seven images 60-s
exposures).
     K. Yoshimoto, Kumage, Yamaguchi, Japan, found a coma of total mag 11.3
and coma diameter 4'.0 on images obtained on 2024 Mar. 10.47 UT with a 0.20-m
f/8 Ritchey-Chretien reflector; he later found a 4'.5 coma of total mag 10.5
on CCD images obtained remotely on Apr. 2.14 UT with a 0.43-m f/6.8 reflector
located at the Utah Desert Remote Observatory (near Beryl Junction, UT, USA).
     K. Kadota, Ageo, reports the following total CCD magnitudes made with a
0.25-m f/5 reflector:  2023 Oct. 18.71 UT, 18.8; Nov. 13.65, 17.9; Dec. 3.57,
17.2; 17.48, 16.6; 2024 Jan. 1.51, 15.5; 15.46, 15.2; 27.42, 14.5; Feb. 12.39,
13.1; 28.46, 12.3; Mar. 14.45, 11.6; 29.47, 10.9; Apr. 14.45, 10.3; 19.44,
9.9.
     Visual total-magnitude and coma-diameter estimates:  Feb. 5.84 UT, 13.4,
0'.9 (W. Hasubick, Buchloe, Germany, 0.44-m reflector); 12.42, [13.0, -- (S.
Yoshida, Ibaraki, Japan, 0.40-m reflector); Mar. 5.84, 10.9, 3'.5 (J. J.
Gonzalez, Leon, Spain,  0.20-m reflector); Apr. 8.89, 9.5, 3' (Gonzales);
12.86, 9.2, 3' (Gonzalez, 20x80 binoculars).
     S. Nakano, Central Bureau, reports the following updated linked orbital
elements for comet 13P from 1347 observations spanning 1887 Aug. 28-2024 Apr.
19 (mean residual 0".9), with non-gravitational parameters A1 = +0.37 +/-
0.02 and A2 = +0.0588 +/- 0.0000.  His earlier linked orbit (cf. CBET 5289)
yields residuals of -8" in R.A. and -22" in Decl. for 2024 April observations.
The comet passed 0.081 AU from Mars on 1887 July 28 and 1.52 AU from Jupiter
on 1889 Jan. 11 UT.  This orbit gives residuals of about +/- 0.35 deg or less
for the 1815 observations.

                    Epoch = 1887 Oct. 16.0 TT
     T = 1887 Oct.  8.97362 TT        Peri. =  65.35617
     e = 0.9309709                    Node  =  86.05746 2000.0
     q = 1.1990812 AU                 Incl. =  44.57066
       a = 17.3706596 AU   n = 0.01361381   P =  72.40 years

                    Epoch = 1956 June 16.0 TT
     T = 1956 June 19.14172 TT        Peri. =  64.64500
     e = 0.9303298                    Node  =  86.10429 2000.0
     q = 1.1784568 AU                 Incl. =  44.60961
       a = 16.9147846 AU   n = 0.01416786   P =  69.57 years

                    Epoch = 2024 June 19.0 TT
     T = 2024 June 30.04867 TT        Peri. =  64.41663
     e = 0.9303079                    Node  =  85.84752 2000.0
     q = 1.1754853 AU                 Incl. =  44.66576
       a = 16.8668467 AU   n = 0.01422831   P =  69.27 years

                    Epoch = 2094 Mar. 24.0 TT
     T = 2094 Mar. 20.46759 TT        Peri. =  64.49629
     e = 0.9308261                    Node  =  85.65483 2000.0
     q = 1.1832168 AU                 Incl. =  44.57697
       a = 17.1049702 AU   n = 0.01393223   P =  70.74 years

The comet is at small elongations from the sun now for several months.  It
is running about a magnitude brighter in April than the ephemeris suggested
on CBET 5289.


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

                         (C) Copyright 2024 CBAT
2024 April 29                    (CBET 5389)              Daniel W. E. Green