| 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 |
0.923 |
| 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) |
| 2026-05-12 00:00 |
07:32:19.24 |
+19:28:11.1 |
HIP 36607 |
30.97 |
| 2026-05-12 12:00 |
07:32:30.78 |
+19:27:57.7 |
HIP 36607 |
32.04 |
| 2026-05-13 00:00 |
07:32:42.40 |
+19:27:43.9 |
HIP 36607 |
33.32 |
| 2026-05-13 12:00 |
07:32:54.10 |
+19:27:29.9 |
HIP 36607 |
34.77 |
| 2026-05-14 00:00 |
07:33:05.88 |
+19:27:15.6 |
HIP 36607 |
36.40 |
| 2026-05-14 12:00 |
07:33:17.74 |
+19:27:01.0 |
HIP 36607 |
38.17 |
| 2026-05-15 00:00 |
07:33:29.67 |
+19:26:46.1 |
HIP 36925 |
36.20 |
| 2026-05-15 12:00 |
07:33:41.69 |
+19:26:31.0 |
HIP 36925 |
34.27 |
| 2026-05-16 00:00 |
07:33:53.78 |
+19:26:15.5 |
HIP 36925 |
32.47 |
| 2026-05-16 12:00 |
07:34:05.95 |
+19:25:59.8 |
HIP 36925 |
30.83 |
| 2026-05-17 00:00 |
07:34:18.20 |
+19:25:43.7 |
HIP 36925 |
29.36 |
| 2026-05-17 12:00 |
07:34:30.52 |
+19:25:27.4 |
HIP 36925 |
28.12 |
| 2026-05-18 00:00 |
07:34:42.92 |
+19:25:10.9 |
HIP 37011 |
26.45 |
| 2026-05-18 12:00 |
07:34:55.39 |
+19:24:54.0 |
HIP 37011 |
23.68 |
| 2026-05-19 00:00 |
07:35:07.93 |
+19:24:36.8 |
HIP 37011 |
20.94 |
| 2026-05-19 12:00 |
07:35:20.54 |
+19:24:19.4 |
HIP 37011 |
18.25 |
| 2026-05-20 00:00 |
07:35:33.23 |
+19:24:01.7 |
HIP 37011 |
15.66 |
| 2026-05-20 12:00 |
07:35:45.99 |
+19:23:43.7 |
HIP 37011 |
13.23 |
| 2026-05-21 00:00 |
07:35:58.82 |
+19:23:25.4 |
HIP 37011 |
11.08 |
| 2026-05-21 12:00 |
07:36:11.71 |
+19:23:06.8 |
HIP 37011 |
9.42 |
| 2026-05-22 00:00 |
07:36:24.68 |
+19:22:48.0 |
HIP 37011 |
8.57 |
| 2026-05-22 12:00 |
07:36:37.72 |
+19:22:28.8 |
HIP 37011 |
8.78 |
| 2026-05-23 00:00 |
07:36:50.82 |
+19:22:09.4 |
HIP 37011 |
10.00 |
| 2026-05-23 12:00 |
07:37:03.99 |
+19:21:49.8 |
HIP 37011 |
11.94 |
| 2026-05-24 00:00 |
07:37:17.22 |
+19:21:29.8 |
HIP 37011 |
14.31 |
| 2026-05-24 12:00 |
07:37:30.52 |
+19:21:09.6 |
HIP 37011 |
16.95 |
| 2026-05-25 00:00 |
07:37:43.88 |
+19:20:49.1 |
HIP 37246 |
19.37 |
| 2026-05-25 12:00 |
07:37:57.31 |
+19:20:28.3 |
HIP 37246 |
16.36 |
| 2026-05-26 00:00 |
07:38:10.80 |
+19:20:07.3 |
HIP 37246 |
13.41 |
| 2026-05-26 12:00 |
07:38:24.35 |
+19:19:46.0 |
HIP 37246 |
10.59 |
| 2026-05-27 00:00 |
07:38:37.97 |
+19:19:24.4 |
HIP 37246 |
8.07 |
| 2026-05-27 12:00 |
07:38:51.64 |
+19:19:02.5 |
HIP 37246 |
6.23 |
| 2026-05-28 00:00 |
07:39:05.38 |
+19:18:40.4 |
HIP 37246 |
5.80 |
| 2026-05-28 12:00 |
07:39:19.18 |
+19:18:18.0 |
HIP 37246 |
7.06 |
| 2026-05-29 00:00 |
07:39:33.03 |
+19:17:55.3 |
HIP 37246 |
9.37 |
| 2026-05-29 12:00 |
07:39:46.95 |
+19:17:32.4 |
HIP 37381 |
9.58 |
| 2026-05-30 00:00 |
07:40:00.92 |
+19:17:09.2 |
HIP 37381 |
6.94 |
| 2026-05-30 12:00 |
07:40:14.95 |
+19:16:45.7 |
HIP 37381 |
5.16 |
| 2026-05-31 00:00 |
07:40:29.03 |
+19:16:22.0 |
HIP 37381 |
5.23 |
| 2026-05-31 12:00 |
07:40:43.18 |
+19:15:58.0 |
HIP 37381 |
7.12 |
| 2026-06-01 00:00 |
07:40:57.38 |
+19:15:33.7 |
HIP 37381 |
9.84 |
| 2026-06-01 12:00 |
07:41:11.63 |
+19:15:09.2 |
HIP 37381 |
12.89 |
| 2026-06-02 00:00 |
07:41:25.94 |
+19:14:44.4 |
HIP 37381 |
16.09 |