| Parameter |
Value |
| Designation |
C/1885 X1 (Fabry) |
| Type |
C |
| Perihelion (tp_cal, UTC) |
1886-04-06T10:56:04.807680Z |
| Orbit solution date (soln_date, UTC) |
2021-04-15T23:28:53Z |
| Obs used |
46 |
| NEO |
- |
| M1 |
- |
| K1 |
- |
| PC |
- |
Osculating Elements
| Parameter |
Value |
| Epoch (epoch_cal, TDB) |
1886-01-18.0000000 |
| e |
1.00038711 |
| q (au) |
0.642383 |
| a (au) |
-1659.415920 |
| i (deg) |
82.629776 |
| Ω (om, deg) |
37.962462 |
| ω (w, deg) |
126.588976 |
| M (ma, deg) |
-0.001144 |
Magnitude
Scatter + Global Linear
$$
M_a = (H_0 + n\cdot 2.5\log_{10} r) + \epsilon - 2.5\log_{10}\Phi(\theta) + 5\log_{10}\Delta
$$
$$
\theta = 180^\circ - \alpha
$$
$$
\Phi(\theta) = \frac{\delta_{90} D(\theta) + 1}{\delta_{90} + 1},\quad D(\theta) = k\cdot \Phi_{HG}(\theta; g_f) + (1-k)\cdot \Phi_{HG}(\theta; g_b)
$$
$$
\Phi_{HG}(\theta; g) = \left(\frac{1+g^2}{1+g^2-2g\cos\theta}\right)^{3/2},\quad \Phi_{HG}(90^\circ)=1
$$
Model Parameters
| Parameter |
Value |
| H0 |
- |
| n |
- |
| gf |
- |
| gb |
- |
| k |
- |
| δ90 |
- |
| Parameter |
Symbol |
Range |
Description |
| Absolute magnitude at 1 AU from Sun and Earth |
H0 |
-5 to 20 |
Intrinsic brightness of the comet |
| Photometric slope parameter |
n |
2 to 6 |
Rate of brightness change with heliocentric distance |
| Forward scattering asymmetry factor |
gf |
0.8 to 1 |
Degree of forward scattering |
| Backward scattering asymmetry factor |
gb |
-1 to -0.5 |
Degree of backward scattering |
| Partitioning coefficient |
k |
0.8 to 1 |
Ratio between forward/backward scattering contributions |
| Dust-to-gas brightness ratio |
δ90 |
1 to 10 |
Relative contribution of dust scattering to gas emission |
Reference: EPSC-DPS2025-160
Ephemeris
| Date/Time (UTC) |
RA (J2000) |
Dec (J2000) |
Nearest HIP |
Dist from HIP (arcmin) |
| 2026-09-20 00:00 |
03:21:57.56 |
-45:30:50.6 |
HIP 15545 |
25.63 |
| 2026-09-20 12:00 |
03:21:56.94 |
-45:30:59.8 |
HIP 15545 |
25.44 |
| 2026-09-21 00:00 |
03:21:56.31 |
-45:31:09.0 |
HIP 15545 |
25.25 |
| 2026-09-21 12:00 |
03:21:55.68 |
-45:31:18.2 |
HIP 15545 |
25.06 |
| 2026-09-22 00:00 |
03:21:55.04 |
-45:31:27.3 |
HIP 15545 |
24.88 |
| 2026-09-22 12:00 |
03:21:54.39 |
-45:31:36.4 |
HIP 15545 |
24.69 |
| 2026-09-23 00:00 |
03:21:53.73 |
-45:31:45.4 |
HIP 15545 |
24.50 |
| 2026-09-23 12:00 |
03:21:53.07 |
-45:31:54.4 |
HIP 15545 |
24.31 |
| 2026-09-24 00:00 |
03:21:52.40 |
-45:32:03.4 |
HIP 15545 |
24.12 |
| 2026-09-24 12:00 |
03:21:51.72 |
-45:32:12.3 |
HIP 15545 |
23.93 |
| 2026-09-25 00:00 |
03:21:51.03 |
-45:32:21.2 |
HIP 15545 |
23.74 |
| 2026-09-25 12:00 |
03:21:50.34 |
-45:32:30.0 |
HIP 15545 |
23.55 |
| 2026-09-26 00:00 |
03:21:49.64 |
-45:32:38.7 |
HIP 15545 |
23.36 |
| 2026-09-26 12:00 |
03:21:48.93 |
-45:32:47.4 |
HIP 15545 |
23.17 |
| 2026-09-27 00:00 |
03:21:48.21 |
-45:32:56.1 |
HIP 15545 |
22.98 |
| 2026-09-27 12:00 |
03:21:47.49 |
-45:33:04.7 |
HIP 15545 |
22.79 |
| 2026-09-28 00:00 |
03:21:46.76 |
-45:33:13.3 |
HIP 15545 |
22.60 |
| 2026-09-28 12:00 |
03:21:46.03 |
-45:33:21.8 |
HIP 15545 |
22.40 |
| 2026-09-29 00:00 |
03:21:45.28 |
-45:33:30.2 |
HIP 15545 |
22.21 |
| 2026-09-29 12:00 |
03:21:44.54 |
-45:33:38.6 |
HIP 15545 |
22.02 |
| 2026-09-30 00:00 |
03:21:43.78 |
-45:33:47.0 |
HIP 15545 |
21.83 |
| 2026-09-30 12:00 |
03:21:43.02 |
-45:33:55.3 |
HIP 15545 |
21.64 |
| 2026-10-01 00:00 |
03:21:42.25 |
-45:34:03.5 |
HIP 15545 |
21.44 |
| 2026-10-01 12:00 |
03:21:41.47 |
-45:34:11.7 |
HIP 15545 |
21.25 |
| 2026-10-02 00:00 |
03:21:40.69 |
-45:34:19.8 |
HIP 15545 |
21.06 |
| 2026-10-02 12:00 |
03:21:39.90 |
-45:34:27.9 |
HIP 15545 |
20.87 |
| 2026-10-03 00:00 |
03:21:39.10 |
-45:34:35.9 |
HIP 15545 |
20.67 |
| 2026-10-03 12:00 |
03:21:38.30 |
-45:34:43.9 |
HIP 15545 |
20.48 |
| 2026-10-04 00:00 |
03:21:37.49 |
-45:34:51.8 |
HIP 15545 |
20.29 |
| 2026-10-04 12:00 |
03:21:36.67 |
-45:34:59.6 |
HIP 15545 |
20.10 |
| 2026-10-05 00:00 |
03:21:35.85 |
-45:35:07.4 |
HIP 15545 |
19.90 |
| 2026-10-05 12:00 |
03:21:35.02 |
-45:35:15.1 |
HIP 15545 |
19.71 |
| 2026-10-06 00:00 |
03:21:34.19 |
-45:35:22.8 |
HIP 15545 |
19.52 |
| 2026-10-06 12:00 |
03:21:33.35 |
-45:35:30.4 |
HIP 15545 |
19.32 |
| 2026-10-07 00:00 |
03:21:32.50 |
-45:35:37.9 |
HIP 15545 |
19.13 |
| 2026-10-07 12:00 |
03:21:31.65 |
-45:35:45.4 |
HIP 15545 |
18.94 |
| 2026-10-08 00:00 |
03:21:30.79 |
-45:35:52.8 |
HIP 15545 |
18.75 |
| 2026-10-08 12:00 |
03:21:29.93 |
-45:36:00.1 |
HIP 15545 |
18.55 |
| 2026-10-09 00:00 |
03:21:29.06 |
-45:36:07.4 |
HIP 15545 |
18.36 |
| 2026-10-09 12:00 |
03:21:28.18 |
-45:36:14.6 |
HIP 15545 |
18.17 |
| 2026-10-10 00:00 |
03:21:27.30 |
-45:36:21.7 |
HIP 15545 |
17.98 |
| 2026-10-10 12:00 |
03:21:26.41 |
-45:36:28.8 |
HIP 15545 |
17.79 |
| 2026-10-11 00:00 |
03:21:25.52 |
-45:36:35.8 |
HIP 15545 |
17.60 |