| Parameter |
Value |
| Designation |
C/2021 K2 (MASTER) |
| Type |
C |
| Perihelion (tp_cal, UTC) |
2021-09-09T03:37:31.964160Z |
| Orbit solution date (soln_date, UTC) |
2022-07-16T01:42:47Z |
| Obs used |
80 |
| NEO |
- |
| M1 |
8.000 |
| K1 |
10.000 |
| PC |
- |
| Discovery observation (MPC, UTC) |
2021-05-22T23:28:21.792000Z |
| Discovery magnitude (MPC) |
18.70 R |
| Discovery observatory (MPC) |
K95 · MASTER-SAAO Observatory, Sutherland |
Osculating Elements
| Parameter |
Value |
| Epoch (epoch_cal, TDB) |
2021-10-19.0000000 |
| e |
1.00120074 |
| q (au) |
5.467026 |
| a (au) |
-4553.055334 |
| i (deg) |
100.845478 |
| Ω (om, deg) |
282.245058 |
| ω (w, deg) |
343.321986 |
| M (ma, deg) |
0.000128 |
Magnitude
Scatter + Global Linear
$$
M_a = (10.806 + 2.000\cdot 2.5\log_{10} r) + \epsilon - 2.5\log_{10}\Phi(\theta) + 5\log_{10}\Delta
$$
$$
\theta = 180^\circ - \alpha
$$
$$
\Phi(\theta) = \frac{\delta_{90} D(\theta) + 1}{\delta_{90} + 1},\quad D(\theta) = k\cdot \Phi_{HG}(\theta; g_f) + (1-k)\cdot \Phi_{HG}(\theta; g_b)
$$
$$
\Phi_{HG}(\theta; g) = \left(\frac{1+g^2}{1+g^2-2g\cos\theta}\right)^{3/2},\quad \Phi_{HG}(90^\circ)=1
$$
Model Parameters
| Parameter |
Value |
| H0 |
10.806 |
| n |
2.000 |
| gf |
0.998 |
| gb |
-1.000 |
| 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) |
| 2026-09-20 00:00 |
16:24:17.27 |
+55:20:42.7 |
HIP 80364 |
0.75 |
| 2026-09-20 12:00 |
16:24:20.67 |
+55:19:08.7 |
HIP 80364 |
0.94 |
| 2026-09-21 00:00 |
16:24:24.19 |
+55:17:35.1 |
HIP 80364 |
2.57 |
| 2026-09-21 12:00 |
16:24:27.83 |
+55:16:01.9 |
HIP 80375 |
3.75 |
| 2026-09-22 00:00 |
16:24:31.58 |
+55:14:29.1 |
HIP 80375 |
2.36 |
| 2026-09-22 12:00 |
16:24:35.44 |
+55:12:56.7 |
HIP 80375 |
1.58 |
| 2026-09-23 00:00 |
16:24:39.42 |
+55:11:24.7 |
HIP 80375 |
2.20 |
| 2026-09-23 12:00 |
16:24:43.51 |
+55:09:53.1 |
HIP 80375 |
3.55 |
| 2026-09-24 00:00 |
16:24:47.72 |
+55:08:21.9 |
HIP 80375 |
5.07 |
| 2026-09-24 12:00 |
16:24:52.03 |
+55:06:51.2 |
HIP 80375 |
6.65 |
| 2026-09-25 00:00 |
16:24:56.46 |
+55:05:20.9 |
HIP 80375 |
8.25 |
| 2026-09-25 12:00 |
16:25:00.99 |
+55:03:51.1 |
HIP 80375 |
9.87 |
| 2026-09-26 00:00 |
16:25:05.64 |
+55:02:21.6 |
HIP 80375 |
11.49 |
| 2026-09-26 12:00 |
16:25:10.40 |
+55:00:52.7 |
HIP 80375 |
13.12 |
| 2026-09-27 00:00 |
16:25:15.26 |
+54:59:24.2 |
HIP 80375 |
14.74 |
| 2026-09-27 12:00 |
16:25:20.23 |
+54:57:56.2 |
HIP 80375 |
16.37 |
| 2026-09-28 00:00 |
16:25:25.31 |
+54:56:28.7 |
HIP 80375 |
18.00 |
| 2026-09-28 12:00 |
16:25:30.49 |
+54:55:01.6 |
HIP 80375 |
19.63 |
| 2026-09-29 00:00 |
16:25:35.78 |
+54:53:35.0 |
HIP 80375 |
21.27 |
| 2026-09-29 12:00 |
16:25:41.17 |
+54:52:09.0 |
HIP 80375 |
22.90 |
| 2026-09-30 00:00 |
16:25:46.67 |
+54:50:43.4 |
HIP 80375 |
24.53 |
| 2026-09-30 12:00 |
16:25:52.28 |
+54:49:18.3 |
HIP 80623 |
24.00 |
| 2026-10-01 00:00 |
16:25:57.98 |
+54:47:53.8 |
HIP 80623 |
22.41 |
| 2026-10-01 12:00 |
16:26:03.79 |
+54:46:29.8 |
HIP 80623 |
20.82 |
| 2026-10-02 00:00 |
16:26:09.70 |
+54:45:06.3 |
HIP 80623 |
19.24 |
| 2026-10-02 12:00 |
16:26:15.72 |
+54:43:43.3 |
HIP 80623 |
17.65 |
| 2026-10-03 00:00 |
16:26:21.83 |
+54:42:20.9 |
HIP 80623 |
16.08 |
| 2026-10-03 12:00 |
16:26:28.04 |
+54:40:59.0 |
HIP 80623 |
14.51 |
| 2026-10-04 00:00 |
16:26:34.36 |
+54:39:37.7 |
HIP 80623 |
12.95 |
| 2026-10-04 12:00 |
16:26:40.77 |
+54:38:16.9 |
HIP 80623 |
11.40 |
| 2026-10-05 00:00 |
16:26:47.28 |
+54:36:56.7 |
HIP 80623 |
9.87 |
| 2026-10-05 12:00 |
16:26:53.89 |
+54:35:37.1 |
HIP 80623 |
8.37 |
| 2026-10-06 00:00 |
16:27:00.60 |
+54:34:18.1 |
HIP 80623 |
6.93 |
| 2026-10-06 12:00 |
16:27:07.40 |
+54:32:59.7 |
HIP 80623 |
5.59 |
| 2026-10-07 00:00 |
16:27:14.30 |
+54:31:41.9 |
HIP 80623 |
4.43 |
| 2026-10-07 12:00 |
16:27:21.29 |
+54:30:24.6 |
HIP 80623 |
3.64 |
| 2026-10-08 00:00 |
16:27:28.38 |
+54:29:08.0 |
HIP 80623 |
3.48 |
| 2026-10-08 12:00 |
16:27:35.56 |
+54:27:52.0 |
HIP 80623 |
4.03 |
| 2026-10-09 00:00 |
16:27:42.84 |
+54:26:36.7 |
HIP 80623 |
5.06 |
| 2026-10-09 12:00 |
16:27:50.20 |
+54:25:21.9 |
HIP 80623 |
6.35 |
| 2026-10-10 00:00 |
16:27:57.66 |
+54:24:07.9 |
HIP 80623 |
7.76 |
| 2026-10-10 12:00 |
16:28:05.21 |
+54:22:54.4 |
HIP 80623 |
9.24 |
| 2026-10-11 00:00 |
16:28:12.85 |
+54:21:41.6 |
HIP 80623 |
10.77 |