Comet C/2012 S1 ISON
Comet C/2012 S1 ISON
April, 2013
The comet at the 10th of April was at about 5.78 au from the Sun. The magnitude in red was from 16.6 to 17.0 during the observations. Performing psf-photometry on every frame, 2 different sources next and out of the nucleus were found.
In the picture before the possible postion of the nucleus is shown and the two other sources too, with letter K and B.
October, 2013
The comet here is approaching Mars and it has an apparent magnitude of 15.3 in red. See the figure below for other details:
January, 2014
We tried to find the remnants of the comet, during 2 different nights of observations in Jan. 10 and Jan. 12 from the Figl Observatory. We observed in 3 different fields, see the figure below (The comet should be inside the quadrant of the bottom):
The first night on 3 frames on the same field we found some possible objects (body U2, T2 and J1 in the figure below, comet ISON is inside the box, considering the position given by HORIZONS Web-Interface and the arrow show its supposed motion) only on 2 frames out of 3. Considering the supposed orbital motion of comet ISON, it is seems they are not its remnants. Also these objects are very faint and maybe are fictitious ones.
The table below describes the objects in the frames. SS1 is USNO-B1==1720009540 and SS2 is USNO-B1==1720009541 (just for reference).
| Obj. | UT | R.A. | DEC. | A.M. | Exp.T. | Mag. | Type |
|---|---|---|---|---|---|---|---|
| ISON (JPL) | 18:55:00 | 02 55 20.67 | +82 03 22.3 | 1.206 | ? | ? | |
| 18:59:00 | 02 55 24.06 | +82 03 03.1 | 1.206 | ? | ? | ||
| 19:03:00 | 02 55 27.45 | +82 02 43.9 | 1.207 | ? | ? | ||
| U2 | 18:59:03 | 02 55 41.62 | +82 04 21.40 | 200 | 19.1 | ? | |
| T2 | 18:59:03 | 02 55 54.01 | +82 04 09.00 | 200 | 20.4 | ? | |
| J1 | 18:55:23 | 02 55 25.14 | +82 03 54.38 | 100 | 18.8 | ? | |
SS1 SS2 | 18:59:03 18:59:03 | 02 55 27.29 02 55 27.46 | +82 03 17.10 +82 02 42.94 | 200 200 | 16.0 18.4 | star star |
The second night, still no significative trace of comet ISON or its remnants were found, but only some possible other sources.
Below details:
The frames ranges between 03 20 45.22 and 03 24 34.11 in RA and +78 21 32.69 and 78 25 47.55 in DEC.
Below 2 frames taken at 18 27 36 UT (left) and 18 35 41 UT (right). In the second frames (on the right) no possible new significant objects was detected. The rectangle show the position where ISON should be and the arrow its path between one frame to the other.
| Obj. | UT | R.A. | DEC. | A.M. | Exp.T. | Mag. | Type |
|---|---|---|---|---|---|---|---|
| A1 | 18 27 36 | 03 22 42.02 | +78 24 03.38 | 1.16 | 100 | ? | |
| A3 | 18 27 36 | 03 23 11.38 | +78 21 22.86 | 1.16 | 100 | 20.3±2.0 | ? |
| A4 | 18 27 36 | 03 23 10.33 | +78 23 34.71 | 1.16 | 100 | 17.2±0.1 | ast.? |
| S12 | 18 27 36 | 1.16 | 100 | 13.34±0.01 | star |
A1, A3, A4 and A5 are unindentified objects (new asteroids or fictitious signals), S12 is the star catalogated as USNOB1=1683-002332. Magnitudes are in infrared band.
Below 2 frames taken at 18 35 41 UT (left) and 18 41 39 UT (right). The rectangle show the position where ISON should be and the arrow its path between one frame to the other.
| Obj. | UT | R.A. | Dec. | A.M. | Exp.T. | Mag. | Type |
|---|---|---|---|---|---|---|---|
| D1 | 18 38 45 | 1.16 | 100 | 18.5±0.2 | ? | ||
| D2 | 18 38 45 | 1.16 | 100 | 19.8±1.2 | Ast.? | ||
| E1 | 18 41 39 | 1.16 | 100 | 17.4±0.1 | Ast.? | ||
DS2 DS3 | 18 38 45 18 38 45 | 1.16 1.16 | 100 100 | 18.4±0.3 18.0±0.2 | star star |
D1, D2 and E3 are unindentified objects (new asteroids or fictitious signals). DS1 and DS2 are respectively the star catalogated as USNO-B1==1684-0020629 and USNO_B1==1684-0020630. Magnitudes are in infrared band.
Below 2 frames taken at 18 44 27 UT (left) and 18 47 39 UT (right). The rectangle show the position where ISON should be and the arrow its path between one frame to the other.
| Obj. | UT | R.A. | Dec. | A.M. | Exp.T. | Mag. | Type |
|---|---|---|---|---|---|---|---|
| F1 | 18 44 27 | 03 22 56.02 | +78 21 03.40 | 1.16 | 100 | 19.4±0.9 | Ast.? |
| F2 | 18 44 27 | 03 22 15.11 | +78 22 18.96 | 1.16 | 100 | 18.9±0.5 | Ast.? |
F1 and F2 are unindentified objects (new asteroids or fictitious signals). Magnitudes are in infrared band.
As final result, if comet C/2012 ISON is inside the fields of the analysed frames its magnitude in infrared-band is IISON >18.4 mag in the Jan. 12, 2014.
Credit: Mattia A. Galiazzo/Department of Astrophysics Vienna, Austria