| Parameter |
Value |
| Designation |
C/2017 C2 (PANSTARRS) |
| Type |
C |
| Perihelion (tp_cal, UTC) |
2017-01-21T14:49:52.703040Z |
| Orbit solution date (soln_date, UTC) |
2021-04-15T23:33:30Z |
| Obs used |
97 |
| NEO |
- |
| M1 |
12.400 |
| K1 |
13.000 |
| PC |
- |
Osculating Elements
| Parameter |
Value |
| Epoch (epoch_cal, TDB) |
2017-03-11.0000000 |
| e |
0.97530974 |
| q (au) |
2.430997 |
| a (au) |
98.459722 |
| i (deg) |
118.583896 |
| Ω (om, deg) |
249.819140 |
| ω (w, deg) |
138.775813 |
| M (ma, deg) |
0.048809 |
Magnitude
Scatter + Global Linear
$$
M_a = (10.786 + 6.000\cdot 2.5\log_{10} r) + \epsilon - 2.5\log_{10}\Phi(\theta) + 5\log_{10}\Delta
$$
$$
\theta = 180^\circ - \alpha
$$
$$
\Phi(\theta) = \frac{\delta_{90} D(\theta) + 1}{\delta_{90} + 1},\quad D(\theta) = k\cdot \Phi_{HG}(\theta; g_f) + (1-k)\cdot \Phi_{HG}(\theta; g_b)
$$
$$
\Phi_{HG}(\theta; g) = \left(\frac{1+g^2}{1+g^2-2g\cos\theta}\right)^{3/2},\quad \Phi_{HG}(90^\circ)=1
$$
Model Parameters
| Parameter |
Value |
| H0 |
10.786 |
| n |
6.000 |
| gf |
1.000 |
| gb |
-1.000 |
| k |
0.999 |
| 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) |
| 2026-05-12 00:00 |
00:26:58.90 |
-66:30:05.7 |
HIP 2345 |
26.96 |
| 2026-05-12 12:00 |
00:27:06.65 |
-66:30:53.9 |
HIP 2345 |
27.07 |
| 2026-05-13 00:00 |
00:27:14.35 |
-66:31:42.7 |
HIP 2345 |
27.24 |
| 2026-05-13 12:00 |
00:27:21.98 |
-66:32:32.0 |
HIP 2345 |
27.46 |
| 2026-05-14 00:00 |
00:27:29.54 |
-66:33:21.8 |
HIP 2345 |
27.73 |
| 2026-05-14 12:00 |
00:27:37.05 |
-66:34:12.0 |
HIP 2345 |
28.06 |
| 2026-05-15 00:00 |
00:27:44.48 |
-66:35:02.8 |
HIP 2345 |
28.45 |
| 2026-05-15 12:00 |
00:27:51.85 |
-66:35:54.1 |
HIP 2345 |
28.88 |
| 2026-05-16 00:00 |
00:27:59.16 |
-66:36:45.9 |
HIP 2345 |
29.36 |
| 2026-05-16 12:00 |
00:28:06.39 |
-66:37:38.2 |
HIP 2345 |
29.88 |
| 2026-05-17 00:00 |
00:28:13.56 |
-66:38:30.9 |
HIP 2345 |
30.45 |
| 2026-05-17 12:00 |
00:28:20.66 |
-66:39:24.2 |
HIP 2636 |
31.00 |
| 2026-05-18 00:00 |
00:28:27.69 |
-66:40:17.9 |
HIP 2636 |
30.14 |
| 2026-05-18 12:00 |
00:28:34.65 |
-66:41:12.2 |
HIP 2636 |
29.29 |
| 2026-05-19 00:00 |
00:28:41.54 |
-66:42:06.9 |
HIP 2636 |
28.48 |
| 2026-05-19 12:00 |
00:28:48.35 |
-66:43:02.0 |
HIP 2636 |
27.69 |
| 2026-05-20 00:00 |
00:28:55.10 |
-66:43:57.7 |
HIP 2636 |
26.94 |
| 2026-05-20 12:00 |
00:29:01.77 |
-66:44:53.8 |
HIP 2636 |
26.23 |
| 2026-05-21 00:00 |
00:29:08.37 |
-66:45:50.4 |
HIP 2636 |
25.55 |
| 2026-05-21 12:00 |
00:29:14.90 |
-66:46:47.4 |
HIP 2636 |
24.91 |
| 2026-05-22 00:00 |
00:29:21.35 |
-66:47:44.9 |
HIP 2636 |
24.32 |
| 2026-05-22 12:00 |
00:29:27.73 |
-66:48:42.8 |
HIP 2636 |
23.79 |
| 2026-05-23 00:00 |
00:29:34.03 |
-66:49:41.2 |
HIP 2636 |
23.30 |
| 2026-05-23 12:00 |
00:29:40.26 |
-66:50:40.1 |
HIP 2636 |
22.87 |
| 2026-05-24 00:00 |
00:29:46.41 |
-66:51:39.4 |
HIP 2636 |
22.51 |
| 2026-05-24 12:00 |
00:29:52.48 |
-66:52:39.1 |
HIP 2636 |
22.21 |
| 2026-05-25 00:00 |
00:29:58.48 |
-66:53:39.2 |
HIP 2636 |
21.97 |
| 2026-05-25 12:00 |
00:30:04.39 |
-66:54:39.8 |
HIP 2636 |
21.81 |
| 2026-05-26 00:00 |
00:30:10.23 |
-66:55:40.8 |
HIP 2636 |
21.72 |
| 2026-05-26 12:00 |
00:30:15.99 |
-66:56:42.3 |
HIP 2636 |
21.70 |
| 2026-05-27 00:00 |
00:30:21.67 |
-66:57:44.1 |
HIP 2636 |
21.76 |
| 2026-05-27 12:00 |
00:30:27.27 |
-66:58:46.4 |
HIP 2636 |
21.89 |
| 2026-05-28 00:00 |
00:30:32.79 |
-66:59:49.1 |
HIP 2636 |
22.09 |
| 2026-05-28 12:00 |
00:30:38.23 |
-67:00:52.2 |
HIP 2636 |
22.37 |
| 2026-05-29 00:00 |
00:30:43.59 |
-67:01:55.7 |
HIP 2636 |
22.71 |
| 2026-05-29 12:00 |
00:30:48.86 |
-67:02:59.6 |
HIP 2636 |
23.12 |
| 2026-05-30 00:00 |
00:30:54.05 |
-67:04:03.9 |
HIP 2636 |
23.59 |
| 2026-05-30 12:00 |
00:30:59.16 |
-67:05:08.6 |
HIP 2636 |
24.13 |
| 2026-05-31 00:00 |
00:31:04.19 |
-67:06:13.7 |
HIP 2662 |
23.94 |
| 2026-05-31 12:00 |
00:31:09.13 |
-67:07:19.2 |
HIP 2662 |
22.80 |
| 2026-06-01 00:00 |
00:31:13.98 |
-67:08:25.1 |
HIP 2662 |
21.66 |
| 2026-06-01 12:00 |
00:31:18.75 |
-67:09:31.3 |
HIP 2662 |
20.53 |
| 2026-06-02 00:00 |
00:31:23.43 |
-67:10:38.0 |
HIP 2662 |
19.41 |