| 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) |
| 2026-07-29 00:00 |
16:00:02.85 |
-05:45:25.2 |
HIP 78304 |
15.92 |
| 2026-07-29 12:00 |
16:00:02.18 |
-05:45:27.7 |
HIP 78304 |
15.84 |
| 2026-07-30 00:00 |
16:00:01.53 |
-05:45:30.3 |
HIP 78304 |
15.76 |
| 2026-07-30 12:00 |
16:00:00.88 |
-05:45:33.0 |
HIP 78304 |
15.69 |
| 2026-07-31 00:00 |
16:00:00.24 |
-05:45:35.7 |
HIP 78304 |
15.62 |
| 2026-07-31 12:00 |
15:59:59.62 |
-05:45:38.4 |
HIP 78304 |
15.56 |
| 2026-08-01 00:00 |
15:59:59.01 |
-05:45:41.2 |
HIP 78304 |
15.50 |
| 2026-08-01 12:00 |
15:59:58.41 |
-05:45:44.1 |
HIP 78304 |
15.45 |
| 2026-08-02 00:00 |
15:59:57.82 |
-05:45:47.0 |
HIP 78304 |
15.39 |
| 2026-08-02 12:00 |
15:59:57.25 |
-05:45:50.0 |
HIP 78304 |
15.35 |
| 2026-08-03 00:00 |
15:59:56.68 |
-05:45:53.0 |
HIP 78304 |
15.30 |
| 2026-08-03 12:00 |
15:59:56.13 |
-05:45:56.1 |
HIP 78304 |
15.26 |
| 2026-08-04 00:00 |
15:59:55.59 |
-05:45:59.3 |
HIP 78304 |
15.22 |
| 2026-08-04 12:00 |
15:59:55.07 |
-05:46:02.4 |
HIP 78304 |
15.19 |
| 2026-08-05 00:00 |
15:59:54.55 |
-05:46:05.7 |
HIP 78304 |
15.16 |
| 2026-08-05 12:00 |
15:59:54.05 |
-05:46:09.0 |
HIP 78304 |
15.14 |
| 2026-08-06 00:00 |
15:59:53.56 |
-05:46:12.3 |
HIP 78304 |
15.11 |
| 2026-08-06 12:00 |
15:59:53.08 |
-05:46:15.7 |
HIP 78304 |
15.10 |
| 2026-08-07 00:00 |
15:59:52.61 |
-05:46:19.2 |
HIP 78304 |
15.08 |
| 2026-08-07 12:00 |
15:59:52.16 |
-05:46:22.7 |
HIP 78304 |
15.07 |
| 2026-08-08 00:00 |
15:59:51.72 |
-05:46:26.2 |
HIP 78304 |
15.06 |
| 2026-08-08 12:00 |
15:59:51.29 |
-05:46:29.8 |
HIP 78304 |
15.06 |
| 2026-08-09 00:00 |
15:59:50.87 |
-05:46:33.5 |
HIP 78304 |
15.06 |
| 2026-08-09 12:00 |
15:59:50.47 |
-05:46:37.2 |
HIP 78304 |
15.06 |
| 2026-08-10 00:00 |
15:59:50.08 |
-05:46:40.9 |
HIP 78304 |
15.06 |
| 2026-08-10 12:00 |
15:59:49.70 |
-05:46:44.7 |
HIP 78304 |
15.07 |
| 2026-08-11 00:00 |
15:59:49.34 |
-05:46:48.5 |
HIP 78304 |
15.08 |
| 2026-08-11 12:00 |
15:59:48.98 |
-05:46:52.4 |
HIP 78304 |
15.10 |
| 2026-08-12 00:00 |
15:59:48.64 |
-05:46:56.4 |
HIP 78304 |
15.11 |
| 2026-08-12 12:00 |
15:59:48.31 |
-05:47:00.4 |
HIP 78304 |
15.13 |
| 2026-08-13 00:00 |
15:59:48.00 |
-05:47:04.4 |
HIP 78304 |
15.16 |
| 2026-08-13 12:00 |
15:59:47.70 |
-05:47:08.5 |
HIP 78304 |
15.18 |
| 2026-08-14 00:00 |
15:59:47.41 |
-05:47:12.6 |
HIP 78304 |
15.21 |
| 2026-08-14 12:00 |
15:59:47.13 |
-05:47:16.8 |
HIP 78304 |
15.24 |
| 2026-08-15 00:00 |
15:59:46.87 |
-05:47:21.0 |
HIP 78304 |
15.28 |
| 2026-08-15 12:00 |
15:59:46.62 |
-05:47:25.3 |
HIP 78304 |
15.31 |
| 2026-08-16 00:00 |
15:59:46.38 |
-05:47:29.6 |
HIP 78304 |
15.35 |
| 2026-08-16 12:00 |
15:59:46.15 |
-05:47:33.9 |
HIP 78304 |
15.40 |
| 2026-08-17 00:00 |
15:59:45.94 |
-05:47:38.3 |
HIP 78304 |
15.44 |
| 2026-08-17 12:00 |
15:59:45.74 |
-05:47:42.8 |
HIP 78304 |
15.49 |
| 2026-08-18 00:00 |
15:59:45.56 |
-05:47:47.3 |
HIP 78304 |
15.54 |
| 2026-08-18 12:00 |
15:59:45.38 |
-05:47:51.8 |
HIP 78304 |
15.59 |
| 2026-08-19 00:00 |
15:59:45.22 |
-05:47:56.4 |
HIP 78304 |
15.64 |