[Iaude] CBET 5350: COMET C/2024 C2

[quai at eps.harvard.edu]

                                                  Electronic Telegram No. 5350
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 C2 (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. 1
(discovery observations tabulated below).  Four 45-s w-band survey images
taken in 1".4-1".6 seeing show a condensed head of size 2".0 (full-width-at-
half-maximum) and no tail.

     2024 UT             R.A. (2000) Decl.       Mag.
     Feb.  1.41828    9 51 51.85   +43 21 57.8   20.5
           1.42938    9 51 51.59   +43 21 59.6   20.5
           1.44049    9 51 51.37   +43 22 00.9   20.4
           1.45161    9 51 51.09   +43 22 02.7   20.6
           1.57820    9 51 48.36   +43 22 20.4   20.1

Weryk then identified presumably asteroidal pre-discovery Pan-STARRS2 images
of the comet taken on 2023 Dec. 25.54-25.57 UT (at mag 21.9-22.6), 2024 Jan.
5.67 (mag 21.3), Jan. 20.7 and 21.7 (mag 20.5), and Jan. 23.42-23.45 (mag
20.5-20.9).  He also identified the comet in pre-discovery observations
obtained with the Pan-STARRS1 1.8-m Ritchey-Chretien reflector at Haleakala
on 2024 Jan. 6.58-6.65 (mag 20.8-21.2) and Jan. 22.5 (mag 20.1-20.4).
     M. Jaeger, Vienna, writes that CCD images obtained by E. Prosperi, S.
Prosperi, and himself on Feb. 1.85-1.87 UT with a 0.3-m f/4 reflector
located at Oed, Martinsberg, Austria, show a strongly condensed coma of size
5" and mag 20.0 with a tail 12" long in p.a. 288 degrees.
     The object appeared stellar on CCD images obtained on Feb. 1.92-1.95 by
A. Aletti with a 0.36-m f/7.5 reflector at Varese, Italy (mag 20.2-20.4).  On
Feb. 11.95-11.98, Aletti obtained one-hundred-thirty-three stacked 30-s
exposures with the same telescope (measured by M. Auteri and himself) in 3".7
seeing that show a condensed coma of size 5" that is extended toward the
southwest; the magnitude was measured to be 19.4-19.6.  Eight stacked 120-s
CCD exposures taken remotely by H. Sato (Bunkyo-ku, Tokyo, Japan) on Feb. 11.3
with a 0.61-m f/6.5 astrograph located at the Sierra Remote Observatory near
Auberry, CA, USA, show a strongly condensed coma 7" in diameter with no tail;
the magnitude was 19.5 as measured within a circular aperture of radius 3".8.
     The available astrometry appears on MPEC 2024-C178.  The following two-
body orbital elements by S. Nakano (Central Bureau) are from 54 observations
spanning 2023 Dec. 25-2024 Feb. 11 (mean residual 0".2).  The orbital period
has a formal error of +/- 26.9 days.  There is no close approach to any
major planets.

     T = 2025 Mar. 16.42419 TT        Peri. =  87.81634
     e = 0.4445150                    Node  =  66.43373 2000.0
     q = 8.9869544 AU                 Incl. =  27.28283
       a = 16.1785725 AU   n = 0.01514585   P =  65.1 years

The following ephemeris by the undersigned from the above orbital elements
uses photometric power-law parameters H = 7.5 and 2.5n = 8 for the magnitudes.

Date    TT    R. A. (2000) Decl.     Delta      r     Elong.  Phase  Mag.
2024 01 11    09 58.36   +42 20.8    8.337    9.136   142.3     3.8  19.8
2024 01 21    09 55.64   +42 51.7    8.278    9.129   148.1     3.3  19.8
2024 01 31    09 52.36   +43 18.6    8.246    9.122   151.2     3.0  19.8
2024 02 10    09 48.73   +43 40.0    8.242    9.116   150.8     3.0  19.8
2024 02 20    09 44.98   +43 54.8    8.265    9.110   146.9     3.4  19.8
2024 03 01    09 41.36   +44 02.4    8.315    9.104   140.8     3.9  19.8
2024 03 11    09 38.11   +44 02.6    8.388    9.098   133.3     4.6  19.8
2024 03 21    09 35.44   +43 55.6    8.482    9.092   125.1     5.1  19.8
2024 03 31    09 33.50   +43 41.9    8.593    9.086   116.7     5.6  19.8
2024 04 10    09 32.40   +43 22.3    8.718    9.080   108.2     6.0  19.9
2024 04 20    09 32.20   +42 57.7    8.852    9.075    99.7     6.3  19.9
2024 04 30    09 32.89   +42 29.2    8.991    9.070    91.3     6.4  19.9
2024 05 10    09 34.47   +41 57.4    9.132    9.065    83.0     6.3  20.0
2024 05 20    09 36.88   +41 23.2    9.269    9.060    75.0     6.2  20.0
2024 05 30    09 40.05   +40 47.4    9.401    9.055    67.1     5.9  20.0
2024 06 09    09 43.90   +40 10.5    9.523    9.051    59.5     5.5  20.0
2024 06 19    09 48.34   +39 33.2    9.634    9.046    52.2     5.1  20.1

2024 09 27    10 47.88   +34 29.8    9.737    9.011    41.5     4.2  20.1
2024 10 07    10 53.71   +34 15.9    9.640    9.008    48.4     4.8  20.1
2024 10 17    10 59.21   +34 06.8    9.527    9.005    55.9     5.3  20.0
2024 10 27    11 04.33   +34 02.7    9.400    9.003    63.6     5.7  20.0
2024 11 06    11 08.96   +34 04.1    9.263    9.001    71.7     6.0  20.0
2024 11 16    11 13.04   +34 11.1    9.118    8.999    80.0     6.2  19.9
2024 11 26    11 16.48   +34 23.8    8.969    8.997    88.5     6.3  19.9
2024 12 06    11 19.21   +34 41.9    8.821    8.995    97.1     6.2  19.9
2024 12 16    11 21.14   +35 05.0    8.676    8.994   105.8     6.0  19.8
2024 12 26    11 22.25   +35 32.3    8.541    8.992   114.4     5.7  19.8
2025 01 05    11 22.49   +36 02.9    8.418    8.991   123.0     5.3  19.8
2025 01 15    11 21.87   +36 35.3    8.313    8.990   131.1     4.7  19.7
2025 01 25    11 20.42   +37 07.9    8.228    8.989   138.5     4.2  19.7
2025 02 04    11 18.23   +37 39.0    8.166    8.988   144.7     3.6  19.7
2025 02 14    11 15.43   +38 06.7    8.130    8.988   148.6     3.3  19.7


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 5350)              Daniel W. E. Green