| Parameter |
Value |
| Designation |
P/2021 R1 (PANSTARRS) |
| Type |
P |
| Perihelion (tp_cal, UTC) |
2021-12-17T19:36:46.062720Z |
| Orbit solution date (soln_date, UTC) |
2022-12-08T23:43:17Z |
| Obs used |
127 |
| NEO |
- |
| M1 |
7.500 |
| K1 |
15.250 |
| PC |
- |
| Discovery observation (MPC, UTC) |
2021-09-04T08:31:35.241600Z |
| Discovery magnitude (MPC) |
20.60 w |
| Discovery observatory (MPC) |
F51 · Pan-STARRS 1, Haleakala |
Osculating Elements
| Parameter |
Value |
| Epoch (epoch_cal, TDB) |
2022-02-25.0000000 |
| e |
0.41886575 |
| q (au) |
4.885582 |
| a (au) |
8.406977 |
| i (deg) |
5.521079 |
| Ω (om, deg) |
143.406228 |
| ω (w, deg) |
220.343748 |
| M (ma, deg) |
2.797322 |
Magnitude
Scatter + Global Linear
$$
M_a = (7.514 + 6.000\cdot 2.5\log_{10} r) + \epsilon - 2.5\log_{10}\Phi(\theta) + 5\log_{10}\Delta
$$
$$
\theta = 180^\circ - \alpha
$$
$$
\Phi(\theta) = \frac{\delta_{90} D(\theta) + 1}{\delta_{90} + 1},\quad D(\theta) = k\cdot \Phi_{HG}(\theta; g_f) + (1-k)\cdot \Phi_{HG}(\theta; g_b)
$$
$$
\Phi_{HG}(\theta; g) = \left(\frac{1+g^2}{1+g^2-2g\cos\theta}\right)^{3/2},\quad \Phi_{HG}(90^\circ)=1
$$
Model Parameters
| Parameter |
Value |
| H0 |
7.514 |
| n |
6.000 |
| gf |
0.924 |
| gb |
-0.916 |
| k |
1.000 |
| δ90 |
1.000 |
| 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) |
| 2026-07-29 00:00 |
08:12:00.76 |
+18:02:48.2 |
HIP 40167 |
24.08 |
| 2026-07-29 12:00 |
08:12:17.32 |
+18:02:00.4 |
HIP 40167 |
23.14 |
| 2026-07-30 00:00 |
08:12:33.88 |
+18:01:12.5 |
HIP 40167 |
22.88 |
| 2026-07-30 12:00 |
08:12:50.41 |
+18:00:24.5 |
HIP 40167 |
23.32 |
| 2026-07-31 00:00 |
08:13:06.94 |
+17:59:36.4 |
HIP 40184 |
23.63 |
| 2026-07-31 12:00 |
08:13:23.44 |
+17:58:48.1 |
HIP 40342 |
21.49 |
| 2026-08-01 00:00 |
08:13:39.94 |
+17:57:59.8 |
HIP 40342 |
18.96 |
| 2026-08-01 12:00 |
08:13:56.41 |
+17:57:11.4 |
HIP 40342 |
17.00 |
| 2026-08-02 00:00 |
08:14:12.87 |
+17:56:22.9 |
HIP 40342 |
15.83 |
| 2026-08-02 12:00 |
08:14:29.31 |
+17:55:34.3 |
HIP 40342 |
15.63 |
| 2026-08-03 00:00 |
08:14:45.74 |
+17:54:45.6 |
HIP 40342 |
16.42 |
| 2026-08-03 12:00 |
08:15:02.15 |
+17:53:56.8 |
HIP 40342 |
18.08 |
| 2026-08-04 00:00 |
08:15:18.53 |
+17:53:07.9 |
HIP 40458 |
19.46 |
| 2026-08-04 12:00 |
08:15:34.90 |
+17:52:19.0 |
HIP 40458 |
18.02 |
| 2026-08-05 00:00 |
08:15:51.25 |
+17:51:30.0 |
HIP 40458 |
17.40 |
| 2026-08-05 12:00 |
08:16:07.58 |
+17:50:40.8 |
HIP 40458 |
17.66 |
| 2026-08-06 00:00 |
08:16:23.89 |
+17:49:51.7 |
HIP 40564 |
16.73 |
| 2026-08-06 12:00 |
08:16:40.17 |
+17:49:02.4 |
HIP 40564 |
16.15 |
| 2026-08-07 00:00 |
08:16:56.44 |
+17:48:13.1 |
HIP 40564 |
16.54 |
| 2026-08-07 12:00 |
08:17:12.68 |
+17:47:23.7 |
HIP 40564 |
17.82 |
| 2026-08-08 00:00 |
08:17:28.90 |
+17:46:34.2 |
HIP 40564 |
19.81 |
| 2026-08-08 12:00 |
08:17:45.10 |
+17:45:44.7 |
HIP 40564 |
22.33 |
| 2026-08-09 00:00 |
08:18:01.27 |
+17:44:55.1 |
HIP 40564 |
25.21 |
| 2026-08-09 12:00 |
08:18:17.41 |
+17:44:05.4 |
HIP 40747 |
28.05 |
| 2026-08-10 00:00 |
08:18:33.53 |
+17:43:15.7 |
HIP 40747 |
27.56 |
| 2026-08-10 12:00 |
08:18:49.63 |
+17:42:25.9 |
HIP 40747 |
27.61 |
| 2026-08-11 00:00 |
08:19:05.70 |
+17:41:36.1 |
HIP 40747 |
28.22 |
| 2026-08-11 12:00 |
08:19:21.74 |
+17:40:46.2 |
HIP 40747 |
29.34 |
| 2026-08-12 00:00 |
08:19:37.75 |
+17:39:56.3 |
HIP 40747 |
30.92 |
| 2026-08-12 12:00 |
08:19:53.73 |
+17:39:06.4 |
HIP 40989 |
28.80 |
| 2026-08-13 00:00 |
08:20:09.69 |
+17:38:16.4 |
HIP 40989 |
24.94 |
| 2026-08-13 12:00 |
08:20:25.61 |
+17:37:26.3 |
HIP 40989 |
21.09 |
| 2026-08-14 00:00 |
08:20:41.50 |
+17:36:36.3 |
HIP 40989 |
17.27 |
| 2026-08-14 12:00 |
08:20:57.37 |
+17:35:46.2 |
HIP 40989 |
13.48 |
| 2026-08-15 00:00 |
08:21:13.20 |
+17:34:56.0 |
HIP 40989 |
9.78 |
| 2026-08-15 12:00 |
08:21:29.00 |
+17:34:05.9 |
HIP 40989 |
6.26 |
| 2026-08-16 00:00 |
08:21:44.76 |
+17:33:15.7 |
HIP 40989 |
3.56 |
| 2026-08-16 12:00 |
08:22:00.49 |
+17:32:25.5 |
HIP 40989 |
3.96 |
| 2026-08-17 00:00 |
08:22:16.19 |
+17:31:35.3 |
HIP 40989 |
6.94 |
| 2026-08-17 12:00 |
08:22:31.86 |
+17:30:45.1 |
HIP 40989 |
10.48 |
| 2026-08-18 00:00 |
08:22:47.48 |
+17:29:54.8 |
HIP 40989 |
14.17 |
| 2026-08-18 12:00 |
08:23:03.08 |
+17:29:04.6 |
HIP 40989 |
17.90 |
| 2026-08-19 00:00 |
08:23:18.63 |
+17:28:14.3 |
HIP 40989 |
21.65 |