| 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
$$
M_a = (10.807 + 2.000\cdot 2.5\log_{10} r) + \epsilon - 2.5\log_{10}\Phi(\theta) + 5\log_{10}\Delta
$$
$$
\theta = 180^\circ - \alpha
$$
$$
\Phi(\theta) = \frac{\delta_{90} D(\theta) + 1}{\delta_{90} + 1},\quad D(\theta) = k\cdot \Phi_{HG}(\theta; g_f) + (1-k)\cdot \Phi_{HG}(\theta; g_b)
$$
$$
\Phi_{HG}(\theta; g) = \left(\frac{1+g^2}{1+g^2-2g\cos\theta}\right)^{3/2},\quad \Phi_{HG}(90^\circ)=1
$$
Model Parameters
| Parameter |
Value |
| H0 |
10.807 |
| n |
2.000 |
| gf |
0.997 |
| gb |
-1.000 |
| k |
1.000 |
| δ90 |
9.959 |
| 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) |
| 2026-05-12 00:00 |
17:17:16.73 |
+58:04:21.0 |
HIP 84664 |
19.70 |
| 2026-05-12 12:00 |
17:16:59.08 |
+58:06:04.4 |
HIP 84664 |
19.54 |
| 2026-05-13 00:00 |
17:16:41.33 |
+58:07:46.6 |
HIP 84664 |
19.84 |
| 2026-05-13 12:00 |
17:16:23.49 |
+58:09:27.5 |
HIP 84352 |
18.87 |
| 2026-05-14 00:00 |
17:16:05.55 |
+58:11:07.2 |
HIP 84352 |
16.04 |
| 2026-05-14 12:00 |
17:15:47.53 |
+58:12:45.5 |
HIP 84352 |
13.26 |
| 2026-05-15 00:00 |
17:15:29.42 |
+58:14:22.7 |
HIP 84352 |
10.53 |
| 2026-05-15 12:00 |
17:15:11.21 |
+58:15:58.5 |
HIP 84352 |
7.93 |
| 2026-05-16 00:00 |
17:14:52.93 |
+58:17:33.1 |
HIP 84352 |
5.62 |
| 2026-05-16 12:00 |
17:14:34.56 |
+58:19:06.3 |
HIP 84352 |
4.12 |
| 2026-05-17 00:00 |
17:14:16.11 |
+58:20:38.3 |
HIP 84352 |
4.36 |
| 2026-05-17 12:00 |
17:13:57.57 |
+58:22:08.9 |
HIP 84352 |
6.13 |
| 2026-05-18 00:00 |
17:13:38.96 |
+58:23:38.3 |
HIP 84352 |
8.52 |
| 2026-05-18 12:00 |
17:13:20.28 |
+58:25:06.3 |
HIP 84352 |
11.14 |
| 2026-05-19 00:00 |
17:13:01.51 |
+58:26:33.0 |
HIP 84352 |
13.85 |
| 2026-05-19 12:00 |
17:12:42.68 |
+58:27:58.4 |
HIP 84352 |
16.61 |
| 2026-05-20 00:00 |
17:12:23.77 |
+58:29:22.5 |
HIP 84352 |
19.39 |
| 2026-05-20 12:00 |
17:12:04.80 |
+58:30:45.2 |
HIP 84352 |
22.19 |
| 2026-05-21 00:00 |
17:11:45.75 |
+58:32:06.6 |
HIP 84352 |
24.99 |
| 2026-05-21 12:00 |
17:11:26.65 |
+58:33:26.7 |
HIP 84352 |
27.80 |
| 2026-05-22 00:00 |
17:11:07.47 |
+58:34:45.4 |
HIP 84352 |
30.61 |
| 2026-05-22 12:00 |
17:10:48.24 |
+58:36:02.7 |
HIP 84203 |
31.73 |
| 2026-05-23 00:00 |
17:10:28.95 |
+58:37:18.7 |
HIP 84203 |
31.92 |
| 2026-05-23 12:00 |
17:10:09.60 |
+58:38:33.4 |
HIP 84203 |
32.38 |
| 2026-05-24 00:00 |
17:09:50.19 |
+58:39:46.7 |
HIP 83765 |
31.56 |
| 2026-05-24 12:00 |
17:09:30.73 |
+58:40:58.6 |
HIP 83765 |
30.89 |
| 2026-05-25 00:00 |
17:09:11.21 |
+58:42:09.2 |
HIP 83741 |
28.53 |
| 2026-05-25 12:00 |
17:08:51.65 |
+58:43:18.4 |
HIP 83741 |
26.09 |
| 2026-05-26 00:00 |
17:08:32.04 |
+58:44:26.3 |
HIP 83654 |
23.54 |
| 2026-05-26 12:00 |
17:08:12.38 |
+58:45:32.7 |
HIP 83654 |
20.78 |
| 2026-05-27 00:00 |
17:07:52.67 |
+58:46:37.8 |
HIP 83654 |
18.02 |
| 2026-05-27 12:00 |
17:07:32.92 |
+58:47:41.6 |
HIP 83654 |
15.28 |
| 2026-05-28 00:00 |
17:07:13.14 |
+58:48:43.9 |
HIP 83654 |
12.56 |
| 2026-05-28 12:00 |
17:06:53.31 |
+58:49:44.9 |
HIP 83654 |
9.88 |
| 2026-05-29 00:00 |
17:06:33.44 |
+58:50:44.5 |
HIP 83654 |
7.27 |
| 2026-05-29 12:00 |
17:06:13.54 |
+58:51:42.8 |
HIP 83654 |
4.83 |
| 2026-05-30 00:00 |
17:05:53.60 |
+58:52:39.6 |
HIP 83654 |
3.02 |
| 2026-05-30 12:00 |
17:05:33.64 |
+58:53:35.1 |
HIP 83654 |
3.17 |
| 2026-05-31 00:00 |
17:05:13.64 |
+58:54:29.2 |
HIP 83654 |
5.11 |
| 2026-05-31 12:00 |
17:04:53.61 |
+58:55:21.9 |
HIP 83654 |
7.56 |
| 2026-06-01 00:00 |
17:04:33.56 |
+58:56:13.2 |
HIP 83654 |
10.15 |
| 2026-06-01 12:00 |
17:04:13.48 |
+58:57:03.1 |
HIP 83654 |
12.80 |
| 2026-06-02 00:00 |
17:03:53.38 |
+58:57:51.6 |
HIP 83654 |
15.47 |