| Parameter |
Value |
| Designation |
D/1977 C1 (Skiff-Kosai) |
| Type |
D |
| Perihelion (tp_cal, UTC) |
1976-08-03T23:51:26.127360Z |
| Orbit solution date (soln_date, UTC) |
2021-04-15T23:29:24Z |
| Obs used |
8 |
| NEO |
- |
| M1 |
8.500 |
| K1 |
15.000 |
| PC |
- |
Osculating Elements
| Parameter |
Value |
| Epoch (epoch_cal, TDB) |
1977-02-23.0000000 |
| e |
0.25917112 |
| q (au) |
2.849755 |
| a (au) |
3.846712 |
| i (deg) |
3.201388 |
| Ω (om, deg) |
80.768376 |
| ω (w, deg) |
26.550778 |
| M (ma, deg) |
26.520292 |
Magnitude
Scatter + Global Linear
$$
M_a = (12.449 + 2.000\cdot 2.5\log_{10} r) + \epsilon - 2.5\log_{10}\Phi(\theta) + 5\log_{10}\Delta
$$
$$
\theta = 180^\circ - \alpha
$$
$$
\Phi(\theta) = \frac{\delta_{90} D(\theta) + 1}{\delta_{90} + 1},\quad D(\theta) = k\cdot \Phi_{HG}(\theta; g_f) + (1-k)\cdot \Phi_{HG}(\theta; g_b)
$$
$$
\Phi_{HG}(\theta; g) = \left(\frac{1+g^2}{1+g^2-2g\cos\theta}\right)^{3/2},\quad \Phi_{HG}(90^\circ)=1
$$
Model Parameters
| Parameter |
Value |
| H0 |
12.449 |
| n |
2.000 |
| gf |
1.000 |
| gb |
-0.502 |
| k |
1.000 |
| δ90 |
10.000 |
| 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) |
| 2026-03-26 00:00 |
21:36:39.24 |
-16:34:52.0 |
HIP 106621 |
13.76 |
| 2026-03-26 12:00 |
21:37:04.48 |
-16:33:01.5 |
HIP 106621 |
20.08 |
| 2026-03-27 00:00 |
21:37:29.63 |
-16:31:11.3 |
HIP 106789 |
16.68 |
| 2026-03-27 12:00 |
21:37:54.69 |
-16:29:21.3 |
HIP 106789 |
14.30 |
| 2026-03-28 00:00 |
21:38:19.68 |
-16:27:31.7 |
HIP 106789 |
14.48 |
| 2026-03-28 12:00 |
21:38:44.58 |
-16:25:42.3 |
HIP 106789 |
17.12 |
| 2026-03-29 00:00 |
21:39:09.39 |
-16:23:53.3 |
HIP 106985 |
20.76 |
| 2026-03-29 12:00 |
21:39:34.13 |
-16:22:04.6 |
HIP 106985 |
19.18 |
| 2026-03-30 00:00 |
21:39:58.77 |
-16:20:16.2 |
HIP 106985 |
19.53 |
| 2026-03-30 12:00 |
21:40:23.34 |
-16:18:28.1 |
HIP 106961 |
19.92 |
| 2026-03-31 00:00 |
21:40:47.81 |
-16:16:40.3 |
HIP 106961 |
21.60 |
| 2026-03-31 12:00 |
21:41:12.20 |
-16:14:52.9 |
HIP 106961 |
24.73 |
| 2026-04-01 00:00 |
21:41:36.50 |
-16:13:05.8 |
HIP 106961 |
28.82 |
| 2026-04-01 12:00 |
21:42:00.72 |
-16:11:19.0 |
HIP 107176 |
26.79 |
| 2026-04-02 00:00 |
21:42:24.84 |
-16:09:32.6 |
HIP 107176 |
23.94 |
| 2026-04-02 12:00 |
21:42:48.88 |
-16:07:46.6 |
HIP 107176 |
22.40 |
| 2026-04-03 00:00 |
21:43:12.82 |
-16:06:00.9 |
HIP 107324 |
17.66 |
| 2026-04-03 12:00 |
21:43:36.68 |
-16:04:15.6 |
HIP 107324 |
11.77 |
| 2026-04-04 00:00 |
21:44:00.44 |
-16:02:30.7 |
HIP 107324 |
6.12 |
| 2026-04-04 12:00 |
21:44:24.11 |
-16:00:46.1 |
HIP 107324 |
2.77 |
| 2026-04-05 00:00 |
21:44:47.69 |
-15:59:01.9 |
HIP 107324 |
6.96 |
| 2026-04-05 12:00 |
21:45:11.18 |
-15:57:18.1 |
HIP 107324 |
12.60 |
| 2026-04-06 00:00 |
21:45:34.57 |
-15:55:34.7 |
HIP 107324 |
18.39 |
| 2026-04-06 12:00 |
21:45:57.87 |
-15:53:51.7 |
HIP 107556 |
20.69 |
| 2026-04-07 00:00 |
21:46:21.07 |
-15:52:09.1 |
HIP 107556 |
18.35 |
| 2026-04-07 12:00 |
21:46:44.17 |
-15:50:27.0 |
HIP 107556 |
17.69 |
| 2026-04-08 00:00 |
21:47:07.18 |
-15:48:45.2 |
HIP 107556 |
18.88 |
| 2026-04-08 12:00 |
21:47:30.09 |
-15:47:03.9 |
HIP 107618 |
18.37 |
| 2026-04-09 00:00 |
21:47:52.91 |
-15:45:23.0 |
HIP 107618 |
19.40 |
| 2026-04-09 12:00 |
21:48:15.62 |
-15:43:42.6 |
HIP 107618 |
21.92 |
| 2026-04-10 00:00 |
21:48:38.23 |
-15:42:02.6 |
HIP 107618 |
25.48 |
| 2026-04-10 12:00 |
21:49:00.75 |
-15:40:23.0 |
HIP 107618 |
29.69 |
| 2026-04-11 00:00 |
21:49:23.16 |
-15:38:43.9 |
HIP 107714 |
31.60 |
| 2026-04-11 12:00 |
21:49:45.46 |
-15:37:05.3 |
HIP 107714 |
30.88 |
| 2026-04-12 00:00 |
21:50:07.67 |
-15:35:27.2 |
HIP 107714 |
31.18 |
| 2026-04-12 12:00 |
21:50:29.77 |
-15:33:49.5 |
HIP 107714 |
32.45 |
| 2026-04-13 00:00 |
21:50:51.77 |
-15:32:12.3 |
HIP 107714 |
34.57 |
| 2026-04-13 12:00 |
21:51:13.66 |
-15:30:35.6 |
HIP 107714 |
37.38 |
| 2026-04-14 00:00 |
21:51:35.44 |
-15:28:59.5 |
HIP 108078 |
33.02 |
| 2026-04-14 12:00 |
21:51:57.12 |
-15:27:23.8 |
HIP 108078 |
27.68 |
| 2026-04-15 00:00 |
21:52:18.68 |
-15:25:48.7 |
HIP 108078 |
22.43 |
| 2026-04-15 12:00 |
21:52:40.14 |
-15:24:14.0 |
HIP 108078 |
17.31 |
| 2026-04-16 00:00 |
21:53:01.49 |
-15:22:39.9 |
HIP 108078 |
12.46 |