| 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) |
| 2026-03-26 00:00 |
03:18:42.78 |
-45:10:08.4 |
HIP 15473 |
9.14 |
| 2026-03-26 12:00 |
03:18:43.49 |
-45:09:59.7 |
HIP 15473 |
8.97 |
| 2026-03-27 00:00 |
03:18:44.22 |
-45:09:51.0 |
HIP 15473 |
8.79 |
| 2026-03-27 12:00 |
03:18:44.95 |
-45:09:42.4 |
HIP 15473 |
8.62 |
| 2026-03-28 00:00 |
03:18:45.69 |
-45:09:33.8 |
HIP 15473 |
8.44 |
| 2026-03-28 12:00 |
03:18:46.43 |
-45:09:25.3 |
HIP 15473 |
8.27 |
| 2026-03-29 00:00 |
03:18:47.18 |
-45:09:16.8 |
HIP 15473 |
8.09 |
| 2026-03-29 12:00 |
03:18:47.94 |
-45:09:08.4 |
HIP 15473 |
7.92 |
| 2026-03-30 00:00 |
03:18:48.70 |
-45:09:00.0 |
HIP 15473 |
7.74 |
| 2026-03-30 12:00 |
03:18:49.47 |
-45:08:51.7 |
HIP 15473 |
7.57 |
| 2026-03-31 00:00 |
03:18:50.24 |
-45:08:43.5 |
HIP 15473 |
7.39 |
| 2026-03-31 12:00 |
03:18:51.03 |
-45:08:35.3 |
HIP 15473 |
7.22 |
| 2026-04-01 00:00 |
03:18:51.81 |
-45:08:27.2 |
HIP 15473 |
7.04 |
| 2026-04-01 12:00 |
03:18:52.61 |
-45:08:19.1 |
HIP 15473 |
6.87 |
| 2026-04-02 00:00 |
03:18:53.40 |
-45:08:11.1 |
HIP 15473 |
6.70 |
| 2026-04-02 12:00 |
03:18:54.21 |
-45:08:03.2 |
HIP 15473 |
6.53 |
| 2026-04-03 00:00 |
03:18:55.02 |
-45:07:55.3 |
HIP 15473 |
6.35 |
| 2026-04-03 12:00 |
03:18:55.84 |
-45:07:47.5 |
HIP 15473 |
6.18 |
| 2026-04-04 00:00 |
03:18:56.66 |
-45:07:39.7 |
HIP 15473 |
6.01 |
| 2026-04-04 12:00 |
03:18:57.48 |
-45:07:32.0 |
HIP 15473 |
5.84 |
| 2026-04-05 00:00 |
03:18:58.32 |
-45:07:24.4 |
HIP 15473 |
5.67 |
| 2026-04-05 12:00 |
03:18:59.16 |
-45:07:16.8 |
HIP 15473 |
5.50 |
| 2026-04-06 00:00 |
03:19:00.00 |
-45:07:09.3 |
HIP 15473 |
5.34 |
| 2026-04-06 12:00 |
03:19:00.85 |
-45:07:01.9 |
HIP 15473 |
5.17 |
| 2026-04-07 00:00 |
03:19:01.70 |
-45:06:54.5 |
HIP 15473 |
5.00 |
| 2026-04-07 12:00 |
03:19:02.56 |
-45:06:47.2 |
HIP 15473 |
4.84 |
| 2026-04-08 00:00 |
03:19:03.43 |
-45:06:40.0 |
HIP 15473 |
4.68 |
| 2026-04-08 12:00 |
03:19:04.30 |
-45:06:32.8 |
HIP 15473 |
4.52 |
| 2026-04-09 00:00 |
03:19:05.17 |
-45:06:25.7 |
HIP 15473 |
4.36 |
| 2026-04-09 12:00 |
03:19:06.05 |
-45:06:18.7 |
HIP 15473 |
4.20 |
| 2026-04-10 00:00 |
03:19:06.94 |
-45:06:11.7 |
HIP 15473 |
4.05 |
| 2026-04-10 12:00 |
03:19:07.83 |
-45:06:04.8 |
HIP 15473 |
3.89 |
| 2026-04-11 00:00 |
03:19:08.72 |
-45:05:58.0 |
HIP 15473 |
3.75 |
| 2026-04-11 12:00 |
03:19:09.62 |
-45:05:51.2 |
HIP 15473 |
3.60 |
| 2026-04-12 00:00 |
03:19:10.53 |
-45:05:44.5 |
HIP 15473 |
3.46 |
| 2026-04-12 12:00 |
03:19:11.43 |
-45:05:37.9 |
HIP 15473 |
3.32 |
| 2026-04-13 00:00 |
03:19:12.35 |
-45:05:31.4 |
HIP 15473 |
3.19 |
| 2026-04-13 12:00 |
03:19:13.27 |
-45:05:24.9 |
HIP 15473 |
3.06 |
| 2026-04-14 00:00 |
03:19:14.19 |
-45:05:18.5 |
HIP 15473 |
2.94 |
| 2026-04-14 12:00 |
03:19:15.11 |
-45:05:12.1 |
HIP 15473 |
2.83 |
| 2026-04-15 00:00 |
03:19:16.04 |
-45:05:05.9 |
HIP 15473 |
2.72 |
| 2026-04-15 12:00 |
03:19:16.98 |
-45:04:59.7 |
HIP 15473 |
2.63 |
| 2026-04-16 00:00 |
03:19:17.92 |
-45:04:53.6 |
HIP 15473 |
2.54 |