| Parameter |
Value |
| Designation |
C/2021 Q6 (PANSTARRS) |
| Type |
C |
| Perihelion (tp_cal, UTC) |
2024-03-23T13:47:29.414400Z |
| Orbit solution date (soln_date, UTC) |
2025-09-16T12:42:41Z |
| Obs used |
388 |
| NEO |
- |
| M1 |
5.000 |
| K1 |
10.750 |
| PC |
- |
| Discovery observation (MPC, UTC) |
2021-08-22T12:28:12.316800Z |
| Discovery magnitude (MPC) |
22.25 z |
| Discovery observatory (MPC) |
F51 · Pan-STARRS 1, Haleakala |
Osculating Elements
| Parameter |
Value |
| Epoch (epoch_cal, TDB) |
2023-03-12.0000000 |
| e |
0.99972188 |
| q (au) |
8.709141 |
| a (au) |
31314.293105 |
| i (deg) |
161.847387 |
| Ω (om, deg) |
133.533757 |
| ω (w, deg) |
140.936211 |
| M (ma, deg) |
359.999933 |
Magnitude
Scatter + Global Linear
$$
M_a = (7.902 + 4.541\cdot 2.5\log_{10} r) + \epsilon - 2.5\log_{10}\Phi(\theta) + 5\log_{10}\Delta
$$
$$
\theta = 180^\circ - \alpha
$$
$$
\Phi(\theta) = \frac{\delta_{90} D(\theta) + 1}{\delta_{90} + 1},\quad D(\theta) = k\cdot \Phi_{HG}(\theta; g_f) + (1-k)\cdot \Phi_{HG}(\theta; g_b)
$$
$$
\Phi_{HG}(\theta; g) = \left(\frac{1+g^2}{1+g^2-2g\cos\theta}\right)^{3/2},\quad \Phi_{HG}(90^\circ)=1
$$
Model Parameters
| Parameter |
Value |
| H0 |
7.902 |
| n |
4.541 |
| gf |
0.875 |
| gb |
-0.776 |
| k |
0.823 |
| δ90 |
6.898 |
| 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 |
20:55:07.85 |
-18:34:04.1 |
HIP 103224 |
14.38 |
| 2026-07-29 12:00 |
20:54:49.96 |
-18:35:43.8 |
HIP 103224 |
11.86 |
| 2026-07-30 00:00 |
20:54:32.07 |
-18:37:23.4 |
HIP 103224 |
10.77 |
| 2026-07-30 12:00 |
20:54:14.16 |
-18:39:02.8 |
HIP 103138 |
10.16 |
| 2026-07-31 00:00 |
20:53:56.24 |
-18:40:42.1 |
HIP 103138 |
6.84 |
| 2026-07-31 12:00 |
20:53:38.31 |
-18:42:21.3 |
HIP 103138 |
5.64 |
| 2026-08-01 00:00 |
20:53:20.37 |
-18:44:00.3 |
HIP 103138 |
7.65 |
| 2026-08-01 12:00 |
20:53:02.43 |
-18:45:39.2 |
HIP 103138 |
11.25 |
| 2026-08-02 00:00 |
20:52:44.48 |
-18:47:18.0 |
HIP 103138 |
15.37 |
| 2026-08-02 12:00 |
20:52:26.53 |
-18:48:56.6 |
HIP 103138 |
19.68 |
| 2026-08-03 00:00 |
20:52:08.58 |
-18:50:35.0 |
HIP 103138 |
24.08 |
| 2026-08-03 12:00 |
20:51:50.62 |
-18:52:13.2 |
HIP 103114 |
28.10 |
| 2026-08-04 00:00 |
20:51:32.67 |
-18:53:51.3 |
HIP 103114 |
31.08 |
| 2026-08-04 12:00 |
20:51:14.72 |
-18:55:29.2 |
HIP 102726 |
33.09 |
| 2026-08-05 00:00 |
20:50:56.77 |
-18:57:06.9 |
HIP 102726 |
28.64 |
| 2026-08-05 12:00 |
20:50:38.82 |
-18:58:44.4 |
HIP 102726 |
24.23 |
| 2026-08-06 00:00 |
20:50:20.89 |
-19:00:21.7 |
HIP 102726 |
19.88 |
| 2026-08-06 12:00 |
20:50:02.96 |
-19:01:58.8 |
HIP 102726 |
15.65 |
| 2026-08-07 00:00 |
20:49:45.03 |
-19:03:35.6 |
HIP 102726 |
11.65 |
| 2026-08-07 12:00 |
20:49:27.12 |
-19:05:12.3 |
HIP 102726 |
8.23 |
| 2026-08-08 00:00 |
20:49:09.22 |
-19:06:48.7 |
HIP 102726 |
6.37 |
| 2026-08-08 12:00 |
20:48:51.33 |
-19:08:24.9 |
HIP 102726 |
7.38 |
| 2026-08-09 00:00 |
20:48:33.46 |
-19:10:00.9 |
HIP 102660 |
7.29 |
| 2026-08-09 12:00 |
20:48:15.61 |
-19:11:36.6 |
HIP 102660 |
4.03 |
| 2026-08-10 00:00 |
20:47:57.77 |
-19:13:12.0 |
HIP 102660 |
4.46 |
| 2026-08-10 12:00 |
20:47:39.95 |
-19:14:47.2 |
HIP 102660 |
8.00 |
| 2026-08-11 00:00 |
20:47:22.15 |
-19:16:22.2 |
HIP 102660 |
12.18 |
| 2026-08-11 12:00 |
20:47:04.37 |
-19:17:56.8 |
HIP 102528 |
10.35 |
| 2026-08-12 00:00 |
20:46:46.62 |
-19:19:31.2 |
HIP 102528 |
7.04 |
| 2026-08-12 12:00 |
20:46:28.89 |
-19:21:05.3 |
HIP 102528 |
5.66 |
| 2026-08-13 00:00 |
20:46:11.19 |
-19:22:39.1 |
HIP 102528 |
7.37 |
| 2026-08-13 12:00 |
20:45:53.51 |
-19:24:12.7 |
HIP 102528 |
10.78 |
| 2026-08-14 00:00 |
20:45:35.87 |
-19:25:45.9 |
HIP 102528 |
14.75 |
| 2026-08-14 12:00 |
20:45:18.26 |
-19:27:18.8 |
HIP 102528 |
18.92 |
| 2026-08-15 00:00 |
20:45:00.68 |
-19:28:51.4 |
HIP 102325 |
17.52 |
| 2026-08-15 12:00 |
20:44:43.13 |
-19:30:23.7 |
HIP 102325 |
14.95 |
| 2026-08-16 00:00 |
20:44:25.62 |
-19:31:55.6 |
HIP 102325 |
13.39 |
| 2026-08-16 12:00 |
20:44:08.14 |
-19:33:27.3 |
HIP 102325 |
13.17 |
| 2026-08-17 00:00 |
20:43:50.70 |
-19:34:58.6 |
HIP 102325 |
14.36 |
| 2026-08-17 12:00 |
20:43:33.31 |
-19:36:29.5 |
HIP 102325 |
16.65 |
| 2026-08-18 00:00 |
20:43:15.95 |
-19:38:00.2 |
HIP 102325 |
19.65 |
| 2026-08-18 12:00 |
20:42:58.63 |
-19:39:30.4 |
HIP 102225 |
21.27 |
| 2026-08-19 00:00 |
20:42:41.36 |
-19:41:00.4 |
HIP 102225 |
19.73 |