C/2021 V1 (Rankin)
| Parameter |
Value |
| Designation |
C/2021 V1 (Rankin) |
| Type |
C |
| Perihelion (tp_cal, UTC) |
2022-04-30T08:37:20.375040Z |
| Orbit solution date (soln_date, UTC) |
2022-02-14T01:12:42Z |
| Obs used |
67 |
| NEO |
- |
| M1 |
15.900 |
| K1 |
4.500 |
| PC |
- |
| Discovery observation (MPC, UTC) |
2021-11-05T03:51:31.478400Z |
| Discovery magnitude (MPC) |
20.97 G |
| Discovery observatory (MPC) |
G96 · Mt. Lemmon Survey |
Osculating Elements
| Parameter |
Value |
| Epoch (epoch_cal, TDB) |
2021-11-16.0000000 |
| e |
0.99556441 |
| q (au) |
3.013528 |
| a (au) |
679.397411 |
| i (deg) |
71.440704 |
| Ω (om, deg) |
207.653208 |
| ω (w, deg) |
195.103041 |
| M (ma, deg) |
359.990797 |
Magnitude
Scatter + Global Linear
$$
M_a = (14.742 + 2.000\cdot 2.5\log_{10} r) + \epsilon - 2.5\log_{10}\Phi(\theta) + 5\log_{10}\Delta
$$
$$
\theta = 180^\circ - \alpha
$$
$$
\Phi(\theta) = \frac{\delta_{90} D(\theta) + 1}{\delta_{90} + 1},\quad D(\theta) = k\cdot \Phi_{HG}(\theta; g_f) + (1-k)\cdot \Phi_{HG}(\theta; g_b)
$$
$$
\Phi_{HG}(\theta; g) = \left(\frac{1+g^2}{1+g^2-2g\cos\theta}\right)^{3/2},\quad \Phi_{HG}(90^\circ)=1
$$
Model Parameters
| Parameter |
Value |
| H0 |
14.742 |
| n |
2.000 |
| gf |
1.000 |
| gb |
-0.803 |
| 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) |
| 2026-02-03 00:00 |
11:20:35.55 |
-46:40:11.5 |
HIP 55529 |
18.89 |
| 2026-02-03 12:00 |
11:20:26.19 |
-46:40:29.4 |
HIP 55529 |
20.49 |
| 2026-02-04 00:00 |
11:20:16.75 |
-46:40:46.2 |
HIP 55529 |
22.10 |
| 2026-02-04 12:00 |
11:20:07.23 |
-46:41:01.7 |
HIP 55529 |
23.73 |
| 2026-02-05 00:00 |
11:19:57.63 |
-46:41:16.2 |
HIP 55529 |
25.38 |
| 2026-02-05 12:00 |
11:19:47.96 |
-46:41:29.4 |
HIP 55150 |
24.12 |
| 2026-02-06 00:00 |
11:19:38.21 |
-46:41:41.5 |
HIP 55150 |
22.43 |
| 2026-02-06 12:00 |
11:19:28.39 |
-46:41:52.4 |
HIP 55150 |
20.74 |
| 2026-02-07 00:00 |
11:19:18.50 |
-46:42:02.1 |
HIP 55150 |
19.04 |
| 2026-02-07 12:00 |
11:19:08.54 |
-46:42:10.7 |
HIP 55150 |
17.32 |
| 2026-02-08 00:00 |
11:18:58.50 |
-46:42:18.0 |
HIP 55150 |
15.60 |
| 2026-02-08 12:00 |
11:18:48.40 |
-46:42:24.2 |
HIP 55150 |
13.87 |
| 2026-02-09 00:00 |
11:18:38.23 |
-46:42:29.2 |
HIP 55150 |
12.13 |
| 2026-02-09 12:00 |
11:18:27.99 |
-46:42:32.9 |
HIP 55150 |
10.39 |
| 2026-02-10 00:00 |
11:18:17.69 |
-46:42:35.5 |
HIP 55150 |
8.64 |
| 2026-02-10 12:00 |
11:18:07.32 |
-46:42:36.8 |
HIP 55150 |
6.90 |
| 2026-02-11 00:00 |
11:17:56.89 |
-46:42:36.9 |
HIP 55150 |
5.18 |
| 2026-02-11 12:00 |
11:17:46.40 |
-46:42:35.8 |
HIP 55150 |
3.53 |
| 2026-02-12 00:00 |
11:17:35.85 |
-46:42:33.5 |
HIP 55150 |
2.13 |
| 2026-02-12 12:00 |
11:17:25.24 |
-46:42:30.0 |
HIP 55150 |
1.80 |
| 2026-02-13 00:00 |
11:17:14.57 |
-46:42:25.2 |
HIP 55150 |
2.95 |
| 2026-02-13 12:00 |
11:17:03.85 |
-46:42:19.2 |
HIP 55150 |
4.59 |
| 2026-02-14 00:00 |
11:16:53.07 |
-46:42:12.0 |
HIP 55150 |
6.35 |
| 2026-02-14 12:00 |
11:16:42.23 |
-46:42:03.5 |
HIP 55150 |
8.17 |
| 2026-02-15 00:00 |
11:16:31.35 |
-46:41:53.8 |
HIP 55150 |
10.02 |
| 2026-02-15 12:00 |
11:16:20.41 |
-46:41:42.9 |
HIP 55108 |
11.78 |
| 2026-02-16 00:00 |
11:16:09.42 |
-46:41:30.7 |
HIP 55108 |
12.78 |
| 2026-02-16 12:00 |
11:15:58.39 |
-46:41:17.2 |
HIP 55108 |
13.95 |
| 2026-02-17 00:00 |
11:15:47.30 |
-46:41:02.5 |
HIP 55108 |
15.27 |
| 2026-02-17 12:00 |
11:15:36.18 |
-46:40:46.6 |
HIP 55108 |
16.71 |
| 2026-02-18 00:00 |
11:15:25.01 |
-46:40:29.4 |
HIP 55108 |
18.23 |
| 2026-02-18 12:00 |
11:15:13.79 |
-46:40:11.0 |
HIP 55108 |
19.82 |
| 2026-02-19 00:00 |
11:15:02.54 |
-46:39:51.3 |
HIP 55108 |
21.47 |
| 2026-02-19 12:00 |
11:14:51.25 |
-46:39:30.3 |
HIP 54808 |
19.93 |
| 2026-02-20 00:00 |
11:14:39.92 |
-46:39:08.1 |
HIP 54808 |
18.09 |
| 2026-02-20 12:00 |
11:14:28.55 |
-46:38:44.6 |
HIP 54808 |
16.28 |
| 2026-02-21 00:00 |
11:14:17.15 |
-46:38:19.9 |
HIP 54808 |
14.50 |
| 2026-02-21 12:00 |
11:14:05.71 |
-46:37:53.9 |
HIP 54808 |
12.76 |
| 2026-02-22 00:00 |
11:13:54.24 |
-46:37:26.7 |
HIP 54808 |
11.09 |
| 2026-02-22 12:00 |
11:13:42.75 |
-46:36:58.2 |
HIP 54808 |
9.54 |
| 2026-02-23 00:00 |
11:13:31.22 |
-46:36:28.5 |
HIP 54808 |
8.19 |
| 2026-02-23 12:00 |
11:13:19.67 |
-46:35:57.5 |
HIP 54808 |
7.14 |
| 2026-02-24 00:00 |
11:13:08.09 |
-46:35:25.3 |
HIP 54808 |
6.57 |