| 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) |
| 2026-03-26 00:00 |
16:05:20.18 |
-06:03:14.5 |
HIP 78870 |
11.12 |
| 2026-03-26 12:00 |
16:05:19.37 |
-06:03:06.2 |
HIP 78870 |
11.36 |
| 2026-03-27 00:00 |
16:05:18.54 |
-06:02:57.9 |
HIP 78870 |
11.61 |
| 2026-03-27 12:00 |
16:05:17.70 |
-06:02:49.5 |
HIP 78870 |
11.86 |
| 2026-03-28 00:00 |
16:05:16.85 |
-06:02:41.2 |
HIP 78870 |
12.11 |
| 2026-03-28 12:00 |
16:05:15.99 |
-06:02:32.9 |
HIP 78870 |
12.36 |
| 2026-03-29 00:00 |
16:05:15.12 |
-06:02:24.5 |
HIP 78870 |
12.62 |
| 2026-03-29 12:00 |
16:05:14.24 |
-06:02:16.2 |
HIP 78870 |
12.88 |
| 2026-03-30 00:00 |
16:05:13.35 |
-06:02:07.8 |
HIP 78870 |
13.14 |
| 2026-03-30 12:00 |
16:05:12.44 |
-06:01:59.5 |
HIP 78870 |
13.40 |
| 2026-03-31 00:00 |
16:05:11.53 |
-06:01:51.1 |
HIP 78870 |
13.67 |
| 2026-03-31 12:00 |
16:05:10.60 |
-06:01:42.8 |
HIP 78870 |
13.94 |
| 2026-04-01 00:00 |
16:05:09.66 |
-06:01:34.5 |
HIP 78870 |
14.21 |
| 2026-04-01 12:00 |
16:05:08.71 |
-06:01:26.1 |
HIP 78870 |
14.48 |
| 2026-04-02 00:00 |
16:05:07.76 |
-06:01:17.8 |
HIP 78870 |
14.76 |
| 2026-04-02 12:00 |
16:05:06.79 |
-06:01:09.4 |
HIP 78870 |
15.04 |
| 2026-04-03 00:00 |
16:05:05.81 |
-06:01:01.1 |
HIP 78870 |
15.32 |
| 2026-04-03 12:00 |
16:05:04.82 |
-06:00:52.8 |
HIP 78870 |
15.60 |
| 2026-04-04 00:00 |
16:05:03.82 |
-06:00:44.4 |
HIP 78870 |
15.89 |
| 2026-04-04 12:00 |
16:05:02.81 |
-06:00:36.1 |
HIP 78870 |
16.17 |
| 2026-04-05 00:00 |
16:05:01.78 |
-06:00:27.8 |
HIP 78870 |
16.46 |
| 2026-04-05 12:00 |
16:05:00.75 |
-06:00:19.5 |
HIP 78870 |
16.75 |
| 2026-04-06 00:00 |
16:04:59.71 |
-06:00:11.1 |
HIP 78870 |
17.05 |
| 2026-04-06 12:00 |
16:04:58.66 |
-06:00:02.8 |
HIP 78870 |
17.34 |
| 2026-04-07 00:00 |
16:04:57.60 |
-05:59:54.5 |
HIP 78870 |
17.64 |
| 2026-04-07 12:00 |
16:04:56.53 |
-05:59:46.2 |
HIP 78870 |
17.94 |
| 2026-04-08 00:00 |
16:04:55.45 |
-05:59:37.9 |
HIP 78870 |
18.24 |
| 2026-04-08 12:00 |
16:04:54.36 |
-05:59:29.7 |
HIP 78870 |
18.55 |
| 2026-04-09 00:00 |
16:04:53.26 |
-05:59:21.4 |
HIP 78870 |
18.85 |
| 2026-04-09 12:00 |
16:04:52.15 |
-05:59:13.1 |
HIP 78870 |
19.16 |
| 2026-04-10 00:00 |
16:04:51.03 |
-05:59:04.9 |
HIP 78870 |
19.47 |
| 2026-04-10 12:00 |
16:04:49.90 |
-05:58:56.6 |
HIP 78870 |
19.78 |
| 2026-04-11 00:00 |
16:04:48.76 |
-05:58:48.4 |
HIP 78870 |
20.10 |
| 2026-04-11 12:00 |
16:04:47.61 |
-05:58:40.2 |
HIP 78870 |
20.41 |
| 2026-04-12 00:00 |
16:04:46.46 |
-05:58:32.0 |
HIP 78870 |
20.73 |
| 2026-04-12 12:00 |
16:04:45.29 |
-05:58:23.8 |
HIP 78870 |
21.05 |
| 2026-04-13 00:00 |
16:04:44.12 |
-05:58:15.6 |
HIP 78870 |
21.37 |
| 2026-04-13 12:00 |
16:04:42.94 |
-05:58:07.5 |
HIP 78870 |
21.70 |
| 2026-04-14 00:00 |
16:04:41.74 |
-05:57:59.3 |
HIP 78870 |
22.02 |
| 2026-04-14 12:00 |
16:04:40.54 |
-05:57:51.2 |
HIP 78870 |
22.35 |
| 2026-04-15 00:00 |
16:04:39.34 |
-05:57:43.0 |
HIP 78870 |
22.68 |
| 2026-04-15 12:00 |
16:04:38.12 |
-05:57:34.9 |
HIP 78870 |
23.01 |
| 2026-04-16 00:00 |
16:04:36.89 |
-05:57:26.9 |
HIP 78870 |
23.34 |