| Parameter |
Value |
| Designation |
C/2016 C1 (PANSTARRS) |
| Type |
C |
| Perihelion (tp_cal, UTC) |
2016-02-19T07:06:40.415040Z |
| Orbit solution date (soln_date, UTC) |
2021-04-15T23:33:23Z |
| Obs used |
236 |
| NEO |
- |
| M1 |
6.500 |
| K1 |
8.500 |
| PC |
0.030 |
Osculating Elements
| Parameter |
Value |
| Epoch (epoch_cal, TDB) |
2017-08-02.0000000 |
| e |
1.00512425 |
| q (au) |
8.462645 |
| a (au) |
-1651.490288 |
| i (deg) |
56.178888 |
| Ω (om, deg) |
181.780057 |
| ω (w, deg) |
328.739361 |
| M (ma, deg) |
0.007779 |
Magnitude
Scatter + Global Linear
$$
M_a = (0.005 + 6.000\cdot 2.5\log_{10} r) + \epsilon - 2.5\log_{10}\Phi(\theta) + 5\log_{10}\Delta
$$
$$
\theta = 180^\circ - \alpha
$$
$$
\Phi(\theta) = \frac{\delta_{90} D(\theta) + 1}{\delta_{90} + 1},\quad D(\theta) = k\cdot \Phi_{HG}(\theta; g_f) + (1-k)\cdot \Phi_{HG}(\theta; g_b)
$$
$$
\Phi_{HG}(\theta; g) = \left(\frac{1+g^2}{1+g^2-2g\cos\theta}\right)^{3/2},\quad \Phi_{HG}(90^\circ)=1
$$
Model Parameters
| Parameter |
Value |
| H0 |
0.005 |
| n |
6.000 |
| gf |
1.000 |
| gb |
-0.940 |
| 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
Residuals (Piecewise)
$$\epsilon = a \log_{10} r_{\mathrm{au}} + b$$
| Start (UTC) |
End (UTC) |
a |
b |
| 2016-03-01 |
2020-05-24 |
+17.7347 |
-16.764 |
log10 r = log10(heliocentric distance / AU), Δ = geocentric distance (AU)
Ephemeris
| Date/Time (UTC) |
RA (J2000) |
Dec (J2000) |
Nearest HIP |
Dist from HIP (arcmin) |
| 2026-05-12 00:00 |
16:37:17.10 |
+32:24:25.9 |
HIP 81222 |
36.00 |
| 2026-05-12 12:00 |
16:37:12.13 |
+32:24:59.5 |
HIP 81222 |
35.74 |
| 2026-05-13 00:00 |
16:37:07.13 |
+32:25:32.5 |
HIP 81222 |
35.50 |
| 2026-05-13 12:00 |
16:37:02.12 |
+32:26:05.0 |
HIP 81222 |
35.28 |
| 2026-05-14 00:00 |
16:36:57.08 |
+32:26:36.9 |
HIP 81222 |
35.10 |
| 2026-05-14 12:00 |
16:36:52.03 |
+32:27:08.3 |
HIP 81222 |
34.95 |
| 2026-05-15 00:00 |
16:36:46.96 |
+32:27:39.1 |
HIP 81222 |
34.83 |
| 2026-05-15 12:00 |
16:36:41.88 |
+32:28:09.3 |
HIP 81222 |
34.74 |
| 2026-05-16 00:00 |
16:36:36.77 |
+32:28:39.0 |
HIP 81222 |
34.68 |
| 2026-05-16 12:00 |
16:36:31.66 |
+32:29:08.1 |
HIP 81222 |
34.65 |
| 2026-05-17 00:00 |
16:36:26.52 |
+32:29:36.6 |
HIP 81222 |
34.65 |
| 2026-05-17 12:00 |
16:36:21.37 |
+32:30:04.5 |
HIP 81222 |
34.68 |
| 2026-05-18 00:00 |
16:36:16.21 |
+32:30:31.9 |
HIP 81222 |
34.74 |
| 2026-05-18 12:00 |
16:36:11.04 |
+32:30:58.7 |
HIP 81222 |
34.83 |
| 2026-05-19 00:00 |
16:36:05.85 |
+32:31:24.9 |
HIP 81222 |
34.95 |
| 2026-05-19 12:00 |
16:36:00.65 |
+32:31:50.5 |
HIP 81222 |
35.10 |
| 2026-05-20 00:00 |
16:35:55.43 |
+32:32:15.5 |
HIP 81222 |
35.28 |
| 2026-05-20 12:00 |
16:35:50.21 |
+32:32:40.0 |
HIP 81222 |
35.49 |
| 2026-05-21 00:00 |
16:35:44.97 |
+32:33:03.8 |
HIP 81222 |
35.72 |
| 2026-05-21 12:00 |
16:35:39.73 |
+32:33:27.1 |
HIP 81222 |
35.98 |
| 2026-05-22 00:00 |
16:35:34.47 |
+32:33:49.8 |
HIP 81147 |
35.92 |
| 2026-05-22 12:00 |
16:35:29.21 |
+32:34:11.9 |
HIP 81147 |
35.81 |
| 2026-05-23 00:00 |
16:35:23.94 |
+32:34:33.5 |
HIP 81147 |
35.73 |
| 2026-05-23 12:00 |
16:35:18.66 |
+32:34:54.4 |
HIP 81147 |
35.68 |
| 2026-05-24 00:00 |
16:35:13.37 |
+32:35:14.7 |
HIP 81147 |
35.66 |
| 2026-05-24 12:00 |
16:35:08.07 |
+32:35:34.5 |
HIP 81147 |
35.67 |
| 2026-05-25 00:00 |
16:35:02.77 |
+32:35:53.6 |
HIP 81147 |
35.70 |
| 2026-05-25 12:00 |
16:34:57.46 |
+32:36:12.2 |
HIP 81147 |
35.77 |
| 2026-05-26 00:00 |
16:34:52.15 |
+32:36:30.2 |
HIP 81147 |
35.86 |
| 2026-05-26 12:00 |
16:34:46.84 |
+32:36:47.5 |
HIP 81147 |
35.98 |
| 2026-05-27 00:00 |
16:34:41.51 |
+32:37:04.3 |
HIP 81191 |
35.99 |
| 2026-05-27 12:00 |
16:34:36.19 |
+32:37:20.5 |
HIP 81191 |
35.87 |
| 2026-05-28 00:00 |
16:34:30.86 |
+32:37:36.1 |
HIP 81191 |
35.80 |
| 2026-05-28 12:00 |
16:34:25.53 |
+32:37:51.1 |
HIP 81191 |
35.78 |
| 2026-05-29 00:00 |
16:34:20.20 |
+32:38:05.5 |
HIP 81191 |
35.80 |
| 2026-05-29 12:00 |
16:34:14.86 |
+32:38:19.3 |
HIP 81191 |
35.87 |
| 2026-05-30 00:00 |
16:34:09.52 |
+32:38:32.5 |
HIP 81191 |
35.98 |
| 2026-05-30 12:00 |
16:34:04.19 |
+32:38:45.1 |
HIP 81191 |
36.14 |
| 2026-05-31 00:00 |
16:33:58.85 |
+32:38:57.1 |
HIP 81191 |
36.35 |
| 2026-05-31 12:00 |
16:33:53.51 |
+32:39:08.5 |
HIP 81191 |
36.59 |
| 2026-06-01 00:00 |
16:33:48.18 |
+32:39:19.4 |
HIP 81191 |
36.88 |
| 2026-06-01 12:00 |
16:33:42.84 |
+32:39:29.6 |
HIP 81191 |
37.21 |
| 2026-06-02 00:00 |
16:33:37.51 |
+32:39:39.2 |
HIP 81191 |
37.58 |