| Parameter |
Value |
| Designation |
C/1977 R1 (Kohler) |
| Type |
C |
| Perihelion (tp_cal, UTC) |
1977-11-10T13:40:46.989120Z |
| Orbit solution date (soln_date, UTC) |
2021-04-15T23:29:27Z |
| Obs used |
421 |
| NEO |
- |
| M1 |
7.300 |
| K1 |
13.500 |
| PC |
0.030 |
Osculating Elements
| Parameter |
Value |
| Epoch (epoch_cal, TDB) |
1977-11-01.0000000 |
| e |
0.99954935 |
| q (au) |
0.990576 |
| a (au) |
2198.096723 |
| i (deg) |
48.711865 |
| Ω (om, deg) |
182.522684 |
| ω (w, deg) |
163.486616 |
| M (ma, deg) |
359.999908 |
Magnitude
Scatter + Global Linear
$$
M_a = (6.933 + 5.854\cdot 2.5\log_{10} r) + \epsilon - 2.5\log_{10}\Phi(\theta) + 5\log_{10}\Delta
$$
$$
\theta = 180^\circ - \alpha
$$
$$
\Phi(\theta) = \frac{\delta_{90} D(\theta) + 1}{\delta_{90} + 1},\quad D(\theta) = k\cdot \Phi_{HG}(\theta; g_f) + (1-k)\cdot \Phi_{HG}(\theta; g_b)
$$
$$
\Phi_{HG}(\theta; g) = \left(\frac{1+g^2}{1+g^2-2g\cos\theta}\right)^{3/2},\quad \Phi_{HG}(90^\circ)=1
$$
Model Parameters
| Parameter |
Value |
| H0 |
6.933 |
| n |
5.854 |
| gf |
0.800 |
| gb |
-0.500 |
| k |
0.800 |
| 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) |
| 2026-09-20 00:00 |
10:21:02.30 |
-12:49:05.7 |
HIP 50536 |
31.05 |
| 2026-09-20 12:00 |
10:21:03.71 |
-12:49:16.6 |
HIP 50536 |
31.44 |
| 2026-09-21 00:00 |
10:21:05.11 |
-12:49:27.6 |
HIP 50536 |
31.82 |
| 2026-09-21 12:00 |
10:21:06.50 |
-12:49:38.5 |
HIP 50536 |
32.21 |
| 2026-09-22 00:00 |
10:21:07.89 |
-12:49:49.6 |
HIP 50536 |
32.59 |
| 2026-09-22 12:00 |
10:21:09.28 |
-12:50:00.6 |
HIP 50536 |
32.97 |
| 2026-09-23 00:00 |
10:21:10.65 |
-12:50:11.7 |
HIP 50536 |
33.36 |
| 2026-09-23 12:00 |
10:21:12.03 |
-12:50:22.9 |
HIP 50536 |
33.74 |
| 2026-09-24 00:00 |
10:21:13.40 |
-12:50:34.1 |
HIP 50536 |
34.12 |
| 2026-09-24 12:00 |
10:21:14.76 |
-12:50:45.3 |
HIP 50536 |
34.50 |
| 2026-09-25 00:00 |
10:21:16.11 |
-12:50:56.6 |
HIP 50536 |
34.88 |
| 2026-09-25 12:00 |
10:21:17.46 |
-12:51:07.9 |
HIP 50536 |
35.26 |
| 2026-09-26 00:00 |
10:21:18.80 |
-12:51:19.2 |
HIP 50787 |
35.59 |
| 2026-09-26 12:00 |
10:21:20.14 |
-12:51:30.6 |
HIP 50787 |
35.30 |
| 2026-09-27 00:00 |
10:21:21.47 |
-12:51:42.0 |
HIP 50787 |
35.01 |
| 2026-09-27 12:00 |
10:21:22.80 |
-12:51:53.5 |
HIP 50787 |
34.72 |
| 2026-09-28 00:00 |
10:21:24.11 |
-12:52:05.0 |
HIP 50787 |
34.43 |
| 2026-09-28 12:00 |
10:21:25.43 |
-12:52:16.5 |
HIP 50787 |
34.14 |
| 2026-09-29 00:00 |
10:21:26.73 |
-12:52:28.0 |
HIP 50787 |
33.86 |
| 2026-09-29 12:00 |
10:21:28.03 |
-12:52:39.6 |
HIP 50787 |
33.58 |
| 2026-09-30 00:00 |
10:21:29.32 |
-12:52:51.2 |
HIP 50787 |
33.30 |
| 2026-09-30 12:00 |
10:21:30.60 |
-12:53:02.9 |
HIP 50787 |
33.02 |
| 2026-10-01 00:00 |
10:21:31.88 |
-12:53:14.6 |
HIP 50787 |
32.74 |
| 2026-10-01 12:00 |
10:21:33.15 |
-12:53:26.3 |
HIP 50787 |
32.46 |
| 2026-10-02 00:00 |
10:21:34.41 |
-12:53:38.0 |
HIP 50787 |
32.19 |
| 2026-10-02 12:00 |
10:21:35.67 |
-12:53:49.8 |
HIP 50787 |
31.92 |
| 2026-10-03 00:00 |
10:21:36.92 |
-12:54:01.6 |
HIP 50787 |
31.65 |
| 2026-10-03 12:00 |
10:21:38.16 |
-12:54:13.4 |
HIP 50787 |
31.38 |
| 2026-10-04 00:00 |
10:21:39.39 |
-12:54:25.2 |
HIP 50787 |
31.11 |
| 2026-10-04 12:00 |
10:21:40.62 |
-12:54:37.1 |
HIP 50787 |
30.85 |
| 2026-10-05 00:00 |
10:21:41.83 |
-12:54:49.0 |
HIP 50787 |
30.59 |
| 2026-10-05 12:00 |
10:21:43.04 |
-12:55:00.9 |
HIP 50787 |
30.33 |
| 2026-10-06 00:00 |
10:21:44.24 |
-12:55:12.8 |
HIP 50787 |
30.07 |
| 2026-10-06 12:00 |
10:21:45.44 |
-12:55:24.8 |
HIP 50787 |
29.81 |
| 2026-10-07 00:00 |
10:21:46.62 |
-12:55:36.8 |
HIP 50787 |
29.56 |
| 2026-10-07 12:00 |
10:21:47.80 |
-12:55:48.8 |
HIP 50787 |
29.31 |
| 2026-10-08 00:00 |
10:21:48.97 |
-12:56:00.8 |
HIP 50787 |
29.06 |
| 2026-10-08 12:00 |
10:21:50.13 |
-12:56:12.8 |
HIP 50787 |
28.81 |
| 2026-10-09 00:00 |
10:21:51.28 |
-12:56:24.9 |
HIP 50787 |
28.57 |
| 2026-10-09 12:00 |
10:21:52.42 |
-12:56:36.9 |
HIP 50787 |
28.32 |
| 2026-10-10 00:00 |
10:21:53.56 |
-12:56:49.0 |
HIP 50787 |
28.08 |
| 2026-10-10 12:00 |
10:21:54.68 |
-12:57:01.1 |
HIP 50787 |
27.84 |
| 2026-10-11 00:00 |
10:21:55.80 |
-12:57:13.2 |
HIP 50787 |
27.60 |