| Parameter |
Value |
| Designation |
C/2021 R7 (PANSTARRS) |
| Type |
C |
| Perihelion (tp_cal, UTC) |
2021-04-14T11:28:22.085760Z |
| Orbit solution date (soln_date, UTC) |
2022-12-08T23:43:02Z |
| Obs used |
63 |
| NEO |
- |
| M1 |
7.700 |
| K1 |
14.000 |
| PC |
- |
| Discovery observation (MPC, UTC) |
2021-09-05T10:13:05.577600Z |
| Discovery magnitude (MPC) |
22.01 w |
| Discovery observatory (MPC) |
F52 · Pan-STARRS 2, Haleakala |
Osculating Elements
| Parameter |
Value |
| Epoch (epoch_cal, TDB) |
2021-11-23.0000000 |
| e |
0.99519043 |
| q (au) |
5.640615 |
| a (au) |
1172.790949 |
| i (deg) |
158.854146 |
| Ω (om, deg) |
170.145186 |
| ω (w, deg) |
139.994299 |
| M (ma, deg) |
0.005461 |
Magnitude
Scatter + Global Linear
$$
M_a = (7.384 + 5.410\cdot 2.5\log_{10} r) + \epsilon - 2.5\log_{10}\Phi(\theta) + 5\log_{10}\Delta
$$
$$
\theta = 180^\circ - \alpha
$$
$$
\Phi(\theta) = \frac{\delta_{90} D(\theta) + 1}{\delta_{90} + 1},\quad D(\theta) = k\cdot \Phi_{HG}(\theta; g_f) + (1-k)\cdot \Phi_{HG}(\theta; g_b)
$$
$$
\Phi_{HG}(\theta; g) = \left(\frac{1+g^2}{1+g^2-2g\cos\theta}\right)^{3/2},\quad \Phi_{HG}(90^\circ)=1
$$
Model Parameters
| Parameter |
Value |
| H0 |
7.384 |
| n |
5.410 |
| gf |
0.999 |
| gb |
-0.856 |
| k |
1.000 |
| δ90 |
10.000 |
| 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) |
| 2026-09-20 00:00 |
19:24:14.35 |
-41:08:25.6 |
HIP 95286 |
12.56 |
| 2026-09-20 12:00 |
19:24:07.69 |
-41:08:01.3 |
HIP 95286 |
11.31 |
| 2026-09-21 00:00 |
19:24:01.12 |
-41:07:36.8 |
HIP 95286 |
10.10 |
| 2026-09-21 12:00 |
19:23:54.66 |
-41:07:12.0 |
HIP 95286 |
8.93 |
| 2026-09-22 00:00 |
19:23:48.31 |
-41:06:46.9 |
HIP 95286 |
7.82 |
| 2026-09-22 12:00 |
19:23:42.05 |
-41:06:21.6 |
HIP 95286 |
6.79 |
| 2026-09-23 00:00 |
19:23:35.90 |
-41:05:56.1 |
HIP 95286 |
5.86 |
| 2026-09-23 12:00 |
19:23:29.85 |
-41:05:30.3 |
HIP 95286 |
5.07 |
| 2026-09-24 00:00 |
19:23:23.90 |
-41:05:04.3 |
HIP 95286 |
4.50 |
| 2026-09-24 12:00 |
19:23:18.06 |
-41:04:38.0 |
HIP 95286 |
4.22 |
| 2026-09-25 00:00 |
19:23:12.32 |
-41:04:11.5 |
HIP 95286 |
4.27 |
| 2026-09-25 12:00 |
19:23:06.68 |
-41:03:44.8 |
HIP 95286 |
4.63 |
| 2026-09-26 00:00 |
19:23:01.14 |
-41:03:17.9 |
HIP 95286 |
5.22 |
| 2026-09-26 12:00 |
19:22:55.71 |
-41:02:50.7 |
HIP 95286 |
5.97 |
| 2026-09-27 00:00 |
19:22:50.38 |
-41:02:23.4 |
HIP 95220 |
5.51 |
| 2026-09-27 12:00 |
19:22:45.15 |
-41:01:55.8 |
HIP 95220 |
4.50 |
| 2026-09-28 00:00 |
19:22:40.02 |
-41:01:28.0 |
HIP 95220 |
3.57 |
| 2026-09-28 12:00 |
19:22:35.00 |
-41:01:00.0 |
HIP 95220 |
2.77 |
| 2026-09-29 00:00 |
19:22:30.08 |
-41:00:31.8 |
HIP 95220 |
2.20 |
| 2026-09-29 12:00 |
19:22:25.26 |
-41:00:03.4 |
HIP 95220 |
2.06 |
| 2026-09-30 00:00 |
19:22:20.55 |
-40:59:34.9 |
HIP 95220 |
2.40 |
| 2026-09-30 12:00 |
19:22:15.93 |
-40:59:06.1 |
HIP 95220 |
3.05 |
| 2026-10-01 00:00 |
19:22:11.42 |
-40:58:37.2 |
HIP 95220 |
3.84 |
| 2026-10-01 12:00 |
19:22:07.02 |
-40:58:08.0 |
HIP 95220 |
4.69 |
| 2026-10-02 00:00 |
19:22:02.71 |
-40:57:38.7 |
HIP 95220 |
5.57 |
| 2026-10-02 12:00 |
19:21:58.51 |
-40:57:09.2 |
HIP 95220 |
6.46 |
| 2026-10-03 00:00 |
19:21:54.41 |
-40:56:39.6 |
HIP 95220 |
7.34 |
| 2026-10-03 12:00 |
19:21:50.41 |
-40:56:09.8 |
HIP 95220 |
8.23 |
| 2026-10-04 00:00 |
19:21:46.52 |
-40:55:39.8 |
HIP 95220 |
9.10 |
| 2026-10-04 12:00 |
19:21:42.73 |
-40:55:09.7 |
HIP 95220 |
9.97 |
| 2026-10-05 00:00 |
19:21:39.04 |
-40:54:39.4 |
HIP 95220 |
10.82 |
| 2026-10-05 12:00 |
19:21:35.45 |
-40:54:08.9 |
HIP 95220 |
11.67 |
| 2026-10-06 00:00 |
19:21:31.96 |
-40:53:38.3 |
HIP 95220 |
12.50 |
| 2026-10-06 12:00 |
19:21:28.58 |
-40:53:07.6 |
HIP 95220 |
13.31 |
| 2026-10-07 00:00 |
19:21:25.30 |
-40:52:36.7 |
HIP 95220 |
14.12 |
| 2026-10-07 12:00 |
19:21:22.12 |
-40:52:05.7 |
HIP 95220 |
14.91 |
| 2026-10-08 00:00 |
19:21:19.04 |
-40:51:34.6 |
HIP 95220 |
15.69 |
| 2026-10-08 12:00 |
19:21:16.07 |
-40:51:03.3 |
HIP 95220 |
16.46 |
| 2026-10-09 00:00 |
19:21:13.19 |
-40:50:31.9 |
HIP 95220 |
17.21 |
| 2026-10-09 12:00 |
19:21:10.42 |
-40:50:00.4 |
HIP 94980 |
17.33 |
| 2026-10-10 00:00 |
19:21:07.75 |
-40:49:28.7 |
HIP 94980 |
16.81 |
| 2026-10-10 12:00 |
19:21:05.18 |
-40:48:57.0 |
HIP 94980 |
16.31 |
| 2026-10-11 00:00 |
19:21:02.71 |
-40:48:25.1 |
HIP 94980 |
15.85 |