The C3 non-group comets C/2000 V4, C/2001 T5 and SOHO-2291
I have found this comet in archival C3 images of 2000 November 10/11 on 2005 April 14. It moved close to the projected path of C/2001 T5:
Shown are the C2 field of view and the orbit of C/2001 T5 as it would appear in C3 2000 Nov 11.0 UTC.
White crosses indicate the positions of the new comet at 20:18 and 00:42 UTC and the perihelion position of C/2001 T5.
The numbers give the velocity of 2001 T5 in pixel/hour for C3. The new comet moved with 12.6 pixel/hour between 20:18 and 00:42 UTC.
The new comet seems to follow the path of C/2001 T5 very well.
I have added a third position (for 04:30 UTC) measured by Karl Battams.
Orbital computations by Brian Marsden (2005 April 15) showed very similar orbital elements for the two comets:
| Designation | T | q | peri | node | incl | L | B |
| C/2000 V4 | 2000 Nov 11.46 | 0.0503 | 180.01 | 324.91 | 54.97 | 144.9 | 0.0 |
| C/2001 T5 | 2001 Oct 15.77 | 0.0476 | 179.51 | 327.74 | 55.26 | 147.5 | 0.4 |
Brian Marsden wrote (MPEC 2005-G93):
C/2000 V4 appears to be related to C/2001 T5 (MPEC 2001-V10). This was pointed out by R. Kracht prior to the derivation of the above positions and the orbit computation.
Both comets were remeasured by Karl Battams in 2021 July. He noted for C/2001 T5 "C3: elongated, diffuse, poor obs" and for C/2000 V4 "C3: elongated, slightly diffuse". My orbital solutions from the new measurements are:
| Designation | T | q | peri | node | incl | L | B |
| C/2000 V4 | 2000 Nov 11.45 | 0.0498 | 179.74 | 326.67 | 54.53 | 146.5 | 0.2 |
| C/2001 T5 | 2001 Oct 15.75 | 0.0498 | 176.28 | 329.77 | 57.21 | 147.8 | 3.1 |
For C/2000 V4 12 of 12 measured
positions were used with RMS = 14.05".
For C/2001 T5 19 of 32 measured positions were used with RMS =
21.51".
Rainer Kracht, 2022 January 05
Update 2024 April 21
On 2012 April 23 Bo Zhou had found a small non-group comet in LASCO C3 images, which was numbered as SOHO-2291. Karl Battams measured it in 2023 September and described it as "ex.faint, ex. diffuse, v.poor obs". My orbital determination from 29 of 36 observations gave a parabolic solution quite similar to those of C/2000 V4 (SOHO-942) and C/2001 T5 (SOHO-359).
| Designation | T | q | peri | node | incl | L | B | peak mag |
| C/2000 V4 | 2000 Nov 11.45 | 0.0498 | 179.74 | 326.67 | 54.53 | 146.5 | 0.2 | 7.2 |
| C/2001 T5 | 2001 Oct 15.75 | 0.0498 | 176.28 | 329.77 | 57.21 | 147.8 | 3.1 | 8.5 |
| SOHO-2291 | 2012 Apr 24.08 | 0.0504 | 173.73 | 332.34 | 56.81 | 148.9 | 5.2 | 8.5 |
It is possible to link C/2000 V4 and SOHO-2291 with an orbital period of 5.7 years.
| Designation | T | q | peri | node | incl | L | B | P |
| C/2000 V4 | 2000 Nov 11.47 | 0.0494 | 182.17 | 324.61 | 55.21 | 145.8 | -1.8 | 5.74 |
| 2006 Aug 08.97 | 0.0493 | 182.19 | 324.57 | 55.21 | 145.8 | -1.8 | 5.74 | |
| SOHO-2291 | 2012 Apr 24.15 | 0.0484 | 182.15 | 324.45 | 54.68 | 145.7 | -1.8 | 5.75 |
But SOHO-2291 can also be linked with C/2001 T5.
| Designation | T | q | peri | node | incl | L | B | P |
| C/2001 T5 | 2001 Oct 15.76 | 0.0488 | 178.07 | 328.92 | 56.59 | 147.9 | +1.6 | 5.27 |
| 2007 Jan 25.67 | 0.0490 | 178.08 | 328.90 | 56.45 | 147.8 | +1.6 | 5.28 | |
| SOHO-2291 | 2012 Apr 24.11 | 0.0493 | 177.99 | 328.77 | 56.51 | 147.7 | +1.7 | 5.28 |
So these comets are ckearly related and appear to be of short orbital period.