| Parameter |
Value |
| Designation |
C/1973 W1 (Gibson) |
| Type |
C |
| Perihelion (tp_cal, UTC) |
1973-08-09T22:26:06.357120Z |
| Orbit solution date (soln_date, UTC) |
2021-04-15T23:29:22Z |
| Obs used |
21 |
| NEO |
- |
| M1 |
- |
| K1 |
- |
| PC |
- |
Osculating Elements
| Parameter |
Value |
| Epoch (epoch_cal, TDB) |
1974-03-23.0000000 |
| e |
1.00046050 |
| q (au) |
3.842303 |
| a (au) |
-8343.718944 |
| i (deg) |
108.064665 |
| Ω (om, deg) |
244.597443 |
| ω (w, deg) |
221.267469 |
| M (ma, deg) |
0.000291 |
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 |
16:00:01.49 |
-05:53:57.2 |
HIP 78341 |
14.17 |
| 2026-09-20 12:00 |
16:00:02.15 |
-05:54:03.6 |
HIP 78341 |
14.11 |
| 2026-09-21 00:00 |
16:00:02.82 |
-05:54:10.0 |
HIP 78341 |
14.06 |
| 2026-09-21 12:00 |
16:00:03.50 |
-05:54:16.4 |
HIP 78341 |
14.00 |
| 2026-09-22 00:00 |
16:00:04.19 |
-05:54:22.8 |
HIP 78341 |
13.95 |
| 2026-09-22 12:00 |
16:00:04.89 |
-05:54:29.2 |
HIP 78341 |
13.91 |
| 2026-09-23 00:00 |
16:00:05.61 |
-05:54:35.7 |
HIP 78341 |
13.87 |
| 2026-09-23 12:00 |
16:00:06.33 |
-05:54:42.1 |
HIP 78341 |
13.83 |
| 2026-09-24 00:00 |
16:00:07.07 |
-05:54:48.5 |
HIP 78341 |
13.79 |
| 2026-09-24 12:00 |
16:00:07.82 |
-05:54:55.0 |
HIP 78341 |
13.76 |
| 2026-09-25 00:00 |
16:00:08.58 |
-05:55:01.4 |
HIP 78341 |
13.74 |
| 2026-09-25 12:00 |
16:00:09.35 |
-05:55:07.9 |
HIP 78341 |
13.71 |
| 2026-09-26 00:00 |
16:00:10.13 |
-05:55:14.4 |
HIP 78341 |
13.70 |
| 2026-09-26 12:00 |
16:00:10.92 |
-05:55:20.9 |
HIP 78341 |
13.68 |
| 2026-09-27 00:00 |
16:00:11.73 |
-05:55:27.3 |
HIP 78341 |
13.68 |
| 2026-09-27 12:00 |
16:00:12.54 |
-05:55:33.8 |
HIP 78341 |
13.67 |
| 2026-09-28 00:00 |
16:00:13.36 |
-05:55:40.3 |
HIP 78341 |
13.68 |
| 2026-09-28 12:00 |
16:00:14.20 |
-05:55:46.8 |
HIP 78341 |
13.68 |
| 2026-09-29 00:00 |
16:00:15.05 |
-05:55:53.3 |
HIP 78341 |
13.70 |
| 2026-09-29 12:00 |
16:00:15.91 |
-05:55:59.8 |
HIP 78341 |
13.71 |
| 2026-09-30 00:00 |
16:00:16.77 |
-05:56:06.3 |
HIP 78341 |
13.74 |
| 2026-09-30 12:00 |
16:00:17.65 |
-05:56:12.8 |
HIP 78341 |
13.77 |
| 2026-10-01 00:00 |
16:00:18.54 |
-05:56:19.4 |
HIP 78341 |
13.80 |
| 2026-10-01 12:00 |
16:00:19.44 |
-05:56:25.9 |
HIP 78341 |
13.84 |
| 2026-10-02 00:00 |
16:00:20.35 |
-05:56:32.4 |
HIP 78341 |
13.89 |
| 2026-10-02 12:00 |
16:00:21.27 |
-05:56:38.9 |
HIP 78341 |
13.94 |
| 2026-10-03 00:00 |
16:00:22.20 |
-05:56:45.4 |
HIP 78341 |
14.00 |
| 2026-10-03 12:00 |
16:00:23.14 |
-05:56:51.9 |
HIP 78341 |
14.07 |
| 2026-10-04 00:00 |
16:00:24.10 |
-05:56:58.4 |
HIP 78341 |
14.14 |
| 2026-10-04 12:00 |
16:00:25.06 |
-05:57:04.9 |
HIP 78341 |
14.22 |
| 2026-10-05 00:00 |
16:00:26.03 |
-05:57:11.4 |
HIP 78341 |
14.30 |
| 2026-10-05 12:00 |
16:00:27.01 |
-05:57:17.9 |
HIP 78341 |
14.39 |
| 2026-10-06 00:00 |
16:00:28.00 |
-05:57:24.4 |
HIP 78341 |
14.48 |
| 2026-10-06 12:00 |
16:00:29.00 |
-05:57:30.9 |
HIP 78341 |
14.58 |
| 2026-10-07 00:00 |
16:00:30.01 |
-05:57:37.4 |
HIP 78341 |
14.69 |
| 2026-10-07 12:00 |
16:00:31.04 |
-05:57:43.9 |
HIP 78341 |
14.81 |
| 2026-10-08 00:00 |
16:00:32.07 |
-05:57:50.4 |
HIP 78341 |
14.93 |
| 2026-10-08 12:00 |
16:00:33.11 |
-05:57:56.8 |
HIP 78341 |
15.05 |
| 2026-10-09 00:00 |
16:00:34.16 |
-05:58:03.3 |
HIP 78341 |
15.19 |
| 2026-10-09 12:00 |
16:00:35.22 |
-05:58:09.8 |
HIP 78341 |
15.32 |
| 2026-10-10 00:00 |
16:00:36.28 |
-05:58:16.2 |
HIP 78341 |
15.47 |
| 2026-10-10 12:00 |
16:00:37.36 |
-05:58:22.6 |
HIP 78341 |
15.62 |
| 2026-10-11 00:00 |
16:00:38.45 |
-05:58:29.1 |
HIP 78341 |
15.77 |