[Iaude] CBET 5348: COMET C/2024 C1

[quai at eps.harvard.edu]

                                                  Electronic Telegram No. 5348
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 C/2024 C1 (PANSTARRS)
     R. Weryk, Department of Physics and Astronomy, University of Western
Ontario, reports the discovery of another comet in images obtained with the
Pan-STARRS2 1.8-m Ritchey-Chretien reflector at Haleakala, Hawaii, on Feb. 9
(discovery observations tabulated below);  four 45-s w-band survey images
taken in 0".9-1".1 seeing show a very condensed head of size 1".3 (full-width-
at-half-maximum) with a clear tail 6" long towards p.a. 285 degrees.

     2024 UT             R.A. (2000) Decl.       Mag.
     Feb.  9.40398   10 51 12.81   +25 17 43.2   21.2
           9.41691   10 51 12.50   +25 17 46.7   21.1
           9.42983   10 51 12.20   +25 17 50.2   21.2
           9.44280   10 51 11.89   +25 17 53.8   21.2
           9.52931   10 51 09.85   +25 18 16.8   21.2
           9.53013   10 51 09.81   +25 18 17.0   21.1

Weryk then identified Pan-STARRS2 pre-discovery images of the comet taken on
2023 Dec. 12.6 UT (mag 22.2-22.8), 2024 Jan. 20.5 (mag 21.4-21.6), and Feb.
4.41-4.45 (mag 20.7-21.1), as well as on pre-discovery images taken with the
Pan-STARRS1 1.8-m Ritchey-Chretien reflector at Haleakala on 2024 Jan. 21.5
(mag 21.1-22.1).  Four 45-s w-band survey images taken in 1".1-1".2 seeing
on Jan. 20 show a very condensed head of size 1".5 (FWHM) and a 3" tail toward
p.a. 280 degrees.  Four 45-s w-band survey images taken in 1".8-2".1 seeing
on Feb. 4 show a very condensed head of size 2".2 (FWHM) and a 4" tail toward
p.a. 280 degrees.  Four 45-s Pan-STARRS2 w-band survey images taken in 1".5
seeing on Feb. 10.4 show a very condensed head of size 1".7 (FWHM) with a
tail about 5" long toward p.a. 285 deg.
     After the comet was posted on the Minor Planet Center's PCCP webpage,
H. Sato (Bunkyo-ku, Tokyo, Japan) reported that twelve stacked 120-s CCD
exposures taken remotely on Feb. 11.5 UT with a 0.43-m f/6.8 astrograph
located at the Utah Desert Remote Observatory (near Beryl Junction, UT, USA)
show only a stellar appearance; the magnitude was 20.8 as measured within a
circular aperture of radius 5".7.
     The available astrometry appears on MPEC 2024-C177.  The following two-
body orbital elements by S. Nakano (Central Bureau) are from 30 observations
spanning 2023 Dec. 12-2024 Feb. 13 (mean residual 0".2).

     T = 2024 Aug. 31.32081 TT        Peri. =  94.52184
     e = 0.5819645                    Node  =  83.81504 2000.0
     q = 4.4122988 AU                 Incl. =  14.22718
       a = 10.5548427 AU   n = 0.02874262   P =  34.29 years

The following ephemeris by the undersigned from the above orbital elements
uses photometric power-law parameters H = 13.0 and 2.5n = 8 for the
magnitudes.

Date    TT    R. A. (2000) Decl.     Delta      r     Elong.  Phase  Mag.
2024 01 11    10 57.41   +23 07.2    3.933    4.643   131.5     9.1  21.3
2024 01 21    10 56.54   +23 49.5    3.817    4.625   141.1     7.7  21.2
2024 01 31    10 54.34   +24 34.9    3.724    4.607   150.4     6.1  21.2
2024 02 10    10 50.98   +25 20.4    3.657    4.590   158.5     4.5  21.1
2024 02 20    10 46.79   +26 02.2    3.619    4.573   162.9     3.6  21.1
2024 03 01    10 42.17   +26 36.9    3.609    4.557   160.9     4.1  21.1
2024 03 11    10 37.57   +27 01.9    3.628    4.542   154.1     5.5  21.1
2024 03 21    10 33.45   +27 15.2    3.674    4.528   145.3     7.2  21.1
2024 03 31    10 30.22   +27 16.3    3.743    4.514   135.9     8.9  21.1
2024 04 10    10 28.16   +27 05.2    3.832    4.502   126.6    10.3  21.1
2024 04 20    10 27.47   +26 43.0    3.938    4.490   117.4    11.5  21.2
2024 04 30    10 28.20   +26 10.8    4.056    4.479   108.5    12.3  21.3
2024 05 10    10 30.35   +25 30.1    4.183    4.469    99.9    12.9  21.3
2024 05 20    10 33.85   +24 42.0    4.315    4.459    91.6    13.1  21.4
2024 05 30    10 38.57   +23 47.9    4.447    4.451    83.6    13.1  21.4
2024 06 09    10 44.38   +22 48.6    4.579    4.443    75.9    12.8  21.5
2024 06 19    10 51.15   +21 45.0    4.706    4.436    68.5    12.3  21.5
2024 06 29    10 58.75   +20 37.9    4.828    4.430    61.3    11.6  21.6
2024 07 09    11 07.05   +19 28.0    4.941    4.425    54.3    10.8  21.6
2024 07 19    11 15.94   +18 15.7    5.044    4.421    47.4     9.7  21.7
2024 07 29    11 25.33   +17 01.7    5.136    4.417    40.8     8.6  21.7


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

                         (C) Copyright 2024 CBAT
2024 February 15                 (CBET 5348)              Daniel W. E. Green