| Parameter |
Value |
| Designation |
C/2020 B3 (Rankin) |
| Type |
C |
| Perihelion (tp_cal, UTC) |
2019-10-19T21:22:57Z |
| Orbit solution date (soln_date, UTC) |
2022-07-06T03:12:24Z |
| Obs used |
185 |
| NEO |
- |
| M1 |
14.600 |
| K1 |
4.500 |
| PC |
- |
Osculating Elements
| Parameter |
Value |
| Epoch (epoch_cal, TDB) |
2020-03-13.0000000 |
| e |
0.99826805 |
| q (au) |
3.344460 |
| a (au) |
1931.033136 |
| i (deg) |
20.701635 |
| Ω (om, deg) |
185.824602 |
| ω (w, deg) |
325.092308 |
| M (ma, deg) |
0.001685 |
Magnitude
Scatter + Global Linear
$$
M_a = (16.046 + 2.957\cdot 2.5\log_{10} r) + \epsilon - 2.5\log_{10}\Phi(\theta) + 5\log_{10}\Delta
$$
$$
\theta = 180^\circ - \alpha
$$
$$
\Phi(\theta) = \frac{\delta_{90} D(\theta) + 1}{\delta_{90} + 1},\quad D(\theta) = k\cdot \Phi_{HG}(\theta; g_f) + (1-k)\cdot \Phi_{HG}(\theta; g_b)
$$
$$
\Phi_{HG}(\theta; g) = \left(\frac{1+g^2}{1+g^2-2g\cos\theta}\right)^{3/2},\quad \Phi_{HG}(90^\circ)=1
$$
Model Parameters
| Parameter |
Value |
| H0 |
16.046 |
| n |
2.957 |
| gf |
1.000 |
| gb |
-0.768 |
| k |
0.800 |
| 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) |
| 2026-07-29 00:00 |
18:27:44.53 |
-01:28:55.0 |
HIP 90438 |
8.73 |
| 2026-07-29 12:00 |
18:27:39.54 |
-01:29:18.5 |
HIP 90438 |
7.54 |
| 2026-07-30 00:00 |
18:27:34.59 |
-01:29:42.2 |
HIP 90438 |
6.40 |
| 2026-07-30 12:00 |
18:27:29.67 |
-01:30:06.2 |
HIP 90438 |
5.34 |
| 2026-07-31 00:00 |
18:27:24.79 |
-01:30:30.5 |
HIP 90438 |
4.42 |
| 2026-07-31 12:00 |
18:27:19.94 |
-01:30:55.0 |
HIP 90438 |
3.73 |
| 2026-08-01 00:00 |
18:27:15.12 |
-01:31:19.7 |
HIP 90438 |
3.41 |
| 2026-08-01 12:00 |
18:27:10.34 |
-01:31:44.7 |
HIP 90438 |
3.55 |
| 2026-08-02 00:00 |
18:27:05.60 |
-01:32:09.9 |
HIP 90438 |
4.10 |
| 2026-08-02 12:00 |
18:27:00.89 |
-01:32:35.4 |
HIP 90438 |
4.91 |
| 2026-08-03 00:00 |
18:26:56.22 |
-01:33:01.0 |
HIP 90438 |
5.88 |
| 2026-08-03 12:00 |
18:26:51.59 |
-01:33:26.9 |
HIP 90438 |
6.93 |
| 2026-08-04 00:00 |
18:26:46.99 |
-01:33:53.1 |
HIP 90438 |
8.03 |
| 2026-08-04 12:00 |
18:26:42.43 |
-01:34:19.4 |
HIP 90438 |
9.16 |
| 2026-08-05 00:00 |
18:26:37.91 |
-01:34:46.0 |
HIP 90438 |
10.31 |
| 2026-08-05 12:00 |
18:26:33.43 |
-01:35:12.8 |
HIP 90438 |
11.46 |
| 2026-08-06 00:00 |
18:26:28.98 |
-01:35:39.9 |
HIP 90438 |
12.62 |
| 2026-08-06 12:00 |
18:26:24.58 |
-01:36:07.1 |
HIP 90438 |
13.78 |
| 2026-08-07 00:00 |
18:26:20.21 |
-01:36:34.6 |
HIP 90438 |
14.94 |
| 2026-08-07 12:00 |
18:26:15.89 |
-01:37:02.2 |
HIP 90438 |
16.09 |
| 2026-08-08 00:00 |
18:26:11.61 |
-01:37:30.1 |
HIP 90272 |
16.53 |
| 2026-08-08 12:00 |
18:26:07.36 |
-01:37:58.2 |
HIP 90272 |
15.38 |
| 2026-08-09 00:00 |
18:26:03.16 |
-01:38:26.5 |
HIP 90272 |
14.23 |
| 2026-08-09 12:00 |
18:25:59.00 |
-01:38:55.0 |
HIP 90272 |
13.09 |
| 2026-08-10 00:00 |
18:25:54.89 |
-01:39:23.7 |
HIP 90272 |
11.97 |
| 2026-08-10 12:00 |
18:25:50.81 |
-01:39:52.6 |
HIP 90272 |
10.85 |
| 2026-08-11 00:00 |
18:25:46.78 |
-01:40:21.7 |
HIP 90272 |
9.75 |
| 2026-08-11 12:00 |
18:25:42.79 |
-01:40:51.0 |
HIP 90272 |
8.66 |
| 2026-08-12 00:00 |
18:25:38.85 |
-01:41:20.5 |
HIP 90272 |
7.59 |
| 2026-08-12 12:00 |
18:25:34.95 |
-01:41:50.2 |
HIP 90272 |
6.54 |
| 2026-08-13 00:00 |
18:25:31.10 |
-01:42:20.0 |
HIP 90272 |
5.51 |
| 2026-08-13 12:00 |
18:25:27.29 |
-01:42:50.0 |
HIP 90272 |
4.52 |
| 2026-08-14 00:00 |
18:25:23.52 |
-01:43:20.3 |
HIP 90272 |
3.60 |
| 2026-08-14 12:00 |
18:25:19.81 |
-01:43:50.6 |
HIP 90272 |
2.78 |
| 2026-08-15 00:00 |
18:25:16.13 |
-01:44:21.2 |
HIP 90272 |
2.20 |
| 2026-08-15 12:00 |
18:25:12.51 |
-01:44:51.9 |
HIP 90272 |
2.05 |
| 2026-08-16 00:00 |
18:25:08.93 |
-01:45:22.8 |
HIP 90272 |
2.39 |
| 2026-08-16 12:00 |
18:25:05.40 |
-01:45:53.9 |
HIP 90272 |
3.06 |
| 2026-08-17 00:00 |
18:25:01.91 |
-01:46:25.1 |
HIP 90272 |
3.88 |
| 2026-08-17 12:00 |
18:24:58.47 |
-01:46:56.5 |
HIP 90272 |
4.77 |
| 2026-08-18 00:00 |
18:24:55.09 |
-01:47:28.0 |
HIP 90240 |
5.63 |
| 2026-08-18 12:00 |
18:24:51.74 |
-01:47:59.7 |
HIP 90240 |
4.76 |
| 2026-08-19 00:00 |
18:24:48.45 |
-01:48:31.6 |
HIP 90240 |
3.95 |