C/2015 W1 (Gibbs)
| Parameter |
Value |
| Designation |
C/2015 W1 (Gibbs) |
| Type |
C |
| Perihelion (tp_cal, UTC) |
2016-05-17T04:39:36.486720Z |
| Orbit solution date (soln_date, UTC) |
2021-04-15T23:33:17Z |
| Obs used |
355 |
| NEO |
- |
| M1 |
12.700 |
| K1 |
9.500 |
| PC |
0.030 |
Osculating Elements
| Parameter |
Value |
| Epoch (epoch_cal, TDB) |
2016-01-02.0000000 |
| e |
1.00128700 |
| q (au) |
2.231883 |
| a (au) |
-1734.174037 |
| i (deg) |
87.318151 |
| Ω (om, deg) |
114.314858 |
| ω (w, deg) |
48.113799 |
| M (ma, deg) |
-0.001859 |
Magnitude
Scatter + Global Linear
$$
M_a = (14.313 + 2.054\cdot 2.5\log_{10} r) + \epsilon - 2.5\log_{10}\Phi(\theta) + 5\log_{10}\Delta
$$
$$
\theta = 180^\circ - \alpha
$$
$$
\Phi(\theta) = \frac{\delta_{90} D(\theta) + 1}{\delta_{90} + 1},\quad D(\theta) = k\cdot \Phi_{HG}(\theta; g_f) + (1-k)\cdot \Phi_{HG}(\theta; g_b)
$$
$$
\Phi_{HG}(\theta; g) = \left(\frac{1+g^2}{1+g^2-2g\cos\theta}\right)^{3/2},\quad \Phi_{HG}(90^\circ)=1
$$
Model Parameters
| Parameter |
Value |
| H0 |
14.313 |
| n |
2.054 |
| gf |
0.982 |
| gb |
-0.916 |
| k |
0.999 |
| δ90 |
1.000 |
| 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) |
| 2026-02-03 00:00 |
20:00:39.88 |
-32:36:22.2 |
HIP 98480 |
25.17 |
| 2026-02-03 12:00 |
20:00:45.49 |
-32:36:19.0 |
HIP 98480 |
25.39 |
| 2026-02-04 00:00 |
20:00:51.08 |
-32:36:15.9 |
HIP 98480 |
25.67 |
| 2026-02-04 12:00 |
20:00:56.66 |
-32:36:13.0 |
HIP 98499 |
25.96 |
| 2026-02-05 00:00 |
20:01:02.23 |
-32:36:10.2 |
HIP 98499 |
26.11 |
| 2026-02-05 12:00 |
20:01:07.78 |
-32:36:07.6 |
HIP 98499 |
26.31 |
| 2026-02-06 00:00 |
20:01:13.31 |
-32:36:05.1 |
HIP 98499 |
26.57 |
| 2026-02-06 12:00 |
20:01:18.83 |
-32:36:02.8 |
HIP 98499 |
26.87 |
| 2026-02-07 00:00 |
20:01:24.33 |
-32:36:00.6 |
HIP 98499 |
27.23 |
| 2026-02-07 12:00 |
20:01:29.82 |
-32:35:58.6 |
HIP 98499 |
27.63 |
| 2026-02-08 00:00 |
20:01:35.29 |
-32:35:56.7 |
HIP 98499 |
28.07 |
| 2026-02-08 12:00 |
20:01:40.74 |
-32:35:55.0 |
HIP 98499 |
28.55 |
| 2026-02-09 00:00 |
20:01:46.18 |
-32:35:53.4 |
HIP 98499 |
29.07 |
| 2026-02-09 12:00 |
20:01:51.60 |
-32:35:52.0 |
HIP 98499 |
29.63 |
| 2026-02-10 00:00 |
20:01:57.00 |
-32:35:50.8 |
HIP 98499 |
30.22 |
| 2026-02-10 12:00 |
20:02:02.38 |
-32:35:49.7 |
HIP 98499 |
30.84 |
| 2026-02-11 00:00 |
20:02:07.75 |
-32:35:48.8 |
HIP 98499 |
31.49 |
| 2026-02-11 12:00 |
20:02:13.09 |
-32:35:48.0 |
HIP 98499 |
32.17 |
| 2026-02-12 00:00 |
20:02:18.42 |
-32:35:47.4 |
HIP 98499 |
32.87 |
| 2026-02-12 12:00 |
20:02:23.72 |
-32:35:46.9 |
HIP 98499 |
33.59 |
| 2026-02-13 00:00 |
20:02:29.01 |
-32:35:46.7 |
HIP 98782 |
34.27 |
| 2026-02-13 12:00 |
20:02:34.27 |
-32:35:46.5 |
HIP 98782 |
33.77 |
| 2026-02-14 00:00 |
20:02:39.52 |
-32:35:46.6 |
HIP 98782 |
33.31 |
| 2026-02-14 12:00 |
20:02:44.74 |
-32:35:46.8 |
HIP 98782 |
32.89 |
| 2026-02-15 00:00 |
20:02:49.94 |
-32:35:47.1 |
HIP 98782 |
32.50 |
| 2026-02-15 12:00 |
20:02:55.12 |
-32:35:47.7 |
HIP 98782 |
32.15 |
| 2026-02-16 00:00 |
20:03:00.28 |
-32:35:48.4 |
HIP 98782 |
31.83 |
| 2026-02-16 12:00 |
20:03:05.41 |
-32:35:49.2 |
HIP 98782 |
31.55 |
| 2026-02-17 00:00 |
20:03:10.52 |
-32:35:50.2 |
HIP 98782 |
31.32 |
| 2026-02-17 12:00 |
20:03:15.61 |
-32:35:51.4 |
HIP 98782 |
31.12 |
| 2026-02-18 00:00 |
20:03:20.67 |
-32:35:52.8 |
HIP 98977 |
30.21 |
| 2026-02-18 12:00 |
20:03:25.71 |
-32:35:54.4 |
HIP 98977 |
29.18 |
| 2026-02-19 00:00 |
20:03:30.73 |
-32:35:56.1 |
HIP 98977 |
28.14 |
| 2026-02-19 12:00 |
20:03:35.72 |
-32:35:57.9 |
HIP 98977 |
27.12 |
| 2026-02-20 00:00 |
20:03:40.68 |
-32:36:00.0 |
HIP 98977 |
26.10 |
| 2026-02-20 12:00 |
20:03:45.62 |
-32:36:02.2 |
HIP 98977 |
25.09 |
| 2026-02-21 00:00 |
20:03:50.53 |
-32:36:04.6 |
HIP 98977 |
24.08 |
| 2026-02-21 12:00 |
20:03:55.42 |
-32:36:07.2 |
HIP 98977 |
23.08 |
| 2026-02-22 00:00 |
20:04:00.28 |
-32:36:09.9 |
HIP 98977 |
22.09 |
| 2026-02-22 12:00 |
20:04:05.11 |
-32:36:12.8 |
HIP 98977 |
21.11 |
| 2026-02-23 00:00 |
20:04:09.92 |
-32:36:15.9 |
HIP 98977 |
20.13 |
| 2026-02-23 12:00 |
20:04:14.70 |
-32:36:19.2 |
HIP 98977 |
19.16 |
| 2026-02-24 00:00 |
20:04:19.45 |
-32:36:22.6 |
HIP 98977 |
18.20 |