| Parameter |
Value |
| Designation |
C/2021 A6 (PANSTARRS) |
| Type |
C |
| Perihelion (tp_cal, UTC) |
2021-05-04T03:17:13.050240Z |
| Orbit solution date (soln_date, UTC) |
2024-08-02T01:42:19Z |
| Obs used |
167 |
| NEO |
- |
| M1 |
5.100 |
| K1 |
12.250 |
| PC |
- |
| Discovery observation (MPC, UTC) |
2021-01-08T14:28:45.120000Z |
| Discovery magnitude (MPC) |
20.89 w |
| Discovery observatory (MPC) |
F51 · Pan-STARRS 1, Haleakala |
Osculating Elements
| Parameter |
Value |
| Epoch (epoch_cal, TDB) |
2022-03-24.0000000 |
| e |
0.99923094 |
| q (au) |
7.928456 |
| a (au) |
10309.304354 |
| i (deg) |
75.612049 |
| Ω (om, deg) |
164.079307 |
| ω (w, deg) |
351.692611 |
| M (ma, deg) |
0.000305 |
Magnitude
Scatter + Global Linear
$$
M_a = (5.232 + 4.625\cdot 2.5\log_{10} r) + \epsilon - 2.5\log_{10}\Phi(\theta) + 5\log_{10}\Delta
$$
$$
\theta = 180^\circ - \alpha
$$
$$
\Phi(\theta) = \frac{\delta_{90} D(\theta) + 1}{\delta_{90} + 1},\quad D(\theta) = k\cdot \Phi_{HG}(\theta; g_f) + (1-k)\cdot \Phi_{HG}(\theta; g_b)
$$
$$
\Phi_{HG}(\theta; g) = \left(\frac{1+g^2}{1+g^2-2g\cos\theta}\right)^{3/2},\quad \Phi_{HG}(90^\circ)=1
$$
Model Parameters
| Parameter |
Value |
| H0 |
5.232 |
| n |
4.625 |
| gf |
0.972 |
| gb |
-0.874 |
| k |
1.000 |
| δ90 |
9.788 |
| 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 |
15:20:20.13 |
+50:29:04.5 |
HIP 75115 |
18.45 |
| 2026-09-20 12:00 |
15:20:31.27 |
+50:27:34.1 |
HIP 74987 |
18.18 |
| 2026-09-21 00:00 |
15:20:42.48 |
+50:26:04.0 |
HIP 74987 |
18.17 |
| 2026-09-21 12:00 |
15:20:53.77 |
+50:24:34.5 |
HIP 74987 |
18.48 |
| 2026-09-22 00:00 |
15:21:05.12 |
+50:23:05.4 |
HIP 74987 |
19.08 |
| 2026-09-22 12:00 |
15:21:16.54 |
+50:21:36.8 |
HIP 75295 |
18.95 |
| 2026-09-23 00:00 |
15:21:28.04 |
+50:20:08.7 |
HIP 75295 |
16.67 |
| 2026-09-23 12:00 |
15:21:39.60 |
+50:18:41.1 |
HIP 75295 |
14.41 |
| 2026-09-24 00:00 |
15:21:51.23 |
+50:17:14.0 |
HIP 75295 |
12.16 |
| 2026-09-24 12:00 |
15:22:02.93 |
+50:15:47.3 |
HIP 75295 |
9.96 |
| 2026-09-25 00:00 |
15:22:14.69 |
+50:14:21.2 |
HIP 75295 |
7.84 |
| 2026-09-25 12:00 |
15:22:26.52 |
+50:12:55.6 |
HIP 75295 |
5.89 |
| 2026-09-26 00:00 |
15:22:38.42 |
+50:11:30.5 |
HIP 75295 |
4.38 |
| 2026-09-26 12:00 |
15:22:50.38 |
+50:10:05.9 |
HIP 75295 |
3.84 |
| 2026-09-27 00:00 |
15:23:02.41 |
+50:08:41.8 |
HIP 75295 |
4.64 |
| 2026-09-27 12:00 |
15:23:14.51 |
+50:07:18.3 |
HIP 75295 |
6.29 |
| 2026-09-28 00:00 |
15:23:26.66 |
+50:05:55.2 |
HIP 75295 |
8.30 |
| 2026-09-28 12:00 |
15:23:38.89 |
+50:04:32.8 |
HIP 75295 |
10.47 |
| 2026-09-29 00:00 |
15:23:51.17 |
+50:03:10.8 |
HIP 75295 |
12.72 |
| 2026-09-29 12:00 |
15:24:03.52 |
+50:01:49.4 |
HIP 75295 |
15.02 |
| 2026-09-30 00:00 |
15:24:15.93 |
+50:00:28.5 |
HIP 75295 |
17.35 |
| 2026-09-30 12:00 |
15:24:28.40 |
+49:59:08.2 |
HIP 75531 |
16.87 |
| 2026-10-01 00:00 |
15:24:40.93 |
+49:57:48.5 |
HIP 75531 |
14.48 |
| 2026-10-01 12:00 |
15:24:53.53 |
+49:56:29.3 |
HIP 75531 |
12.09 |
| 2026-10-02 00:00 |
15:25:06.18 |
+49:55:10.7 |
HIP 75531 |
9.71 |
| 2026-10-02 12:00 |
15:25:18.90 |
+49:53:52.6 |
HIP 75531 |
7.37 |
| 2026-10-03 00:00 |
15:25:31.67 |
+49:52:35.1 |
HIP 75531 |
5.10 |
| 2026-10-03 12:00 |
15:25:44.51 |
+49:51:18.3 |
HIP 75531 |
3.10 |
| 2026-10-04 00:00 |
15:25:57.40 |
+49:50:01.9 |
HIP 75531 |
2.26 |
| 2026-10-04 12:00 |
15:26:10.35 |
+49:48:46.2 |
HIP 75531 |
3.55 |
| 2026-10-05 00:00 |
15:26:23.36 |
+49:47:31.1 |
HIP 75531 |
5.67 |
| 2026-10-05 12:00 |
15:26:36.42 |
+49:46:16.6 |
HIP 75531 |
7.98 |
| 2026-10-06 00:00 |
15:26:49.54 |
+49:45:02.7 |
HIP 75531 |
10.36 |
| 2026-10-06 12:00 |
15:27:02.72 |
+49:43:49.4 |
HIP 75531 |
12.78 |
| 2026-10-07 00:00 |
15:27:15.96 |
+49:42:36.7 |
HIP 75531 |
15.21 |
| 2026-10-07 12:00 |
15:27:29.24 |
+49:41:24.6 |
HIP 75531 |
17.65 |
| 2026-10-08 00:00 |
15:27:42.59 |
+49:40:13.2 |
HIP 75531 |
20.11 |
| 2026-10-08 12:00 |
15:27:55.98 |
+49:39:02.4 |
HIP 75531 |
22.57 |
| 2026-10-09 00:00 |
15:28:09.43 |
+49:37:52.2 |
HIP 75531 |
25.03 |
| 2026-10-09 12:00 |
15:28:22.93 |
+49:36:42.7 |
HIP 75531 |
27.51 |
| 2026-10-10 00:00 |
15:28:36.49 |
+49:35:33.8 |
HIP 75531 |
29.98 |
| 2026-10-10 12:00 |
15:28:50.09 |
+49:34:25.6 |
HIP 75531 |
32.46 |
| 2026-10-11 00:00 |
15:29:03.75 |
+49:33:18.0 |
HIP 75531 |
34.94 |