| 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 |
0.992 |
| gb |
-0.940 |
| k |
1.000 |
| δ90 |
9.998 |
| 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 |
+17.7344 |
-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) |
| 2026-07-29 00:00 |
16:25:42.95 |
+31:57:30.3 |
HIP 80515 |
9.59 |
| 2026-07-29 12:00 |
16:25:40.85 |
+31:56:41.9 |
HIP 80515 |
10.49 |
| 2026-07-30 00:00 |
16:25:38.80 |
+31:55:53.1 |
HIP 80515 |
11.40 |
| 2026-07-30 12:00 |
16:25:36.80 |
+31:55:04.0 |
HIP 80515 |
12.31 |
| 2026-07-31 00:00 |
16:25:34.84 |
+31:54:14.6 |
HIP 80434 |
11.48 |
| 2026-07-31 12:00 |
16:25:32.94 |
+31:53:24.9 |
HIP 80434 |
10.56 |
| 2026-08-01 00:00 |
16:25:31.08 |
+31:52:34.8 |
HIP 80434 |
9.65 |
| 2026-08-01 12:00 |
16:25:29.27 |
+31:51:44.5 |
HIP 80434 |
8.73 |
| 2026-08-02 00:00 |
16:25:27.50 |
+31:50:53.9 |
HIP 80434 |
7.83 |
| 2026-08-02 12:00 |
16:25:25.79 |
+31:50:02.9 |
HIP 80434 |
6.92 |
| 2026-08-03 00:00 |
16:25:24.12 |
+31:49:11.7 |
HIP 80434 |
6.03 |
| 2026-08-03 12:00 |
16:25:22.50 |
+31:48:20.2 |
HIP 80434 |
5.15 |
| 2026-08-04 00:00 |
16:25:20.94 |
+31:47:28.4 |
HIP 80434 |
4.30 |
| 2026-08-04 12:00 |
16:25:19.42 |
+31:46:36.4 |
HIP 80434 |
3.48 |
| 2026-08-05 00:00 |
16:25:17.95 |
+31:45:44.0 |
HIP 80434 |
2.75 |
| 2026-08-05 12:00 |
16:25:16.52 |
+31:44:51.4 |
HIP 80434 |
2.17 |
| 2026-08-06 00:00 |
16:25:15.15 |
+31:43:58.5 |
HIP 80434 |
1.91 |
| 2026-08-06 12:00 |
16:25:13.83 |
+31:43:05.4 |
HIP 80434 |
2.09 |
| 2026-08-07 00:00 |
16:25:12.56 |
+31:42:12.0 |
HIP 80434 |
2.62 |
| 2026-08-07 12:00 |
16:25:11.34 |
+31:41:18.4 |
HIP 80434 |
3.33 |
| 2026-08-08 00:00 |
16:25:10.17 |
+31:40:24.5 |
HIP 80434 |
4.14 |
| 2026-08-08 12:00 |
16:25:09.05 |
+31:39:30.3 |
HIP 80434 |
5.00 |
| 2026-08-09 00:00 |
16:25:07.98 |
+31:38:35.9 |
HIP 80434 |
5.88 |
| 2026-08-09 12:00 |
16:25:06.96 |
+31:37:41.3 |
HIP 80434 |
6.79 |
| 2026-08-10 00:00 |
16:25:05.99 |
+31:36:46.5 |
HIP 80434 |
7.70 |
| 2026-08-10 12:00 |
16:25:05.07 |
+31:35:51.4 |
HIP 80434 |
8.62 |
| 2026-08-11 00:00 |
16:25:04.20 |
+31:34:56.1 |
HIP 80434 |
9.55 |
| 2026-08-11 12:00 |
16:25:03.38 |
+31:34:00.6 |
HIP 80434 |
10.49 |
| 2026-08-12 00:00 |
16:25:02.62 |
+31:33:04.8 |
HIP 80434 |
11.42 |
| 2026-08-12 12:00 |
16:25:01.91 |
+31:32:08.9 |
HIP 80434 |
12.36 |
| 2026-08-13 00:00 |
16:25:01.24 |
+31:31:12.7 |
HIP 80434 |
13.31 |
| 2026-08-13 12:00 |
16:25:00.63 |
+31:30:16.4 |
HIP 80434 |
14.25 |
| 2026-08-14 00:00 |
16:25:00.08 |
+31:29:19.8 |
HIP 80434 |
15.20 |
| 2026-08-14 12:00 |
16:24:59.57 |
+31:28:23.1 |
HIP 80434 |
16.16 |
| 2026-08-15 00:00 |
16:24:59.11 |
+31:27:26.2 |
HIP 80434 |
17.11 |
| 2026-08-15 12:00 |
16:24:58.71 |
+31:26:29.1 |
HIP 80434 |
18.06 |
| 2026-08-16 00:00 |
16:24:58.36 |
+31:25:31.8 |
HIP 80434 |
19.02 |
| 2026-08-16 12:00 |
16:24:58.06 |
+31:24:34.4 |
HIP 80434 |
19.98 |
| 2026-08-17 00:00 |
16:24:57.81 |
+31:23:36.8 |
HIP 80434 |
20.94 |
| 2026-08-17 12:00 |
16:24:57.62 |
+31:22:39.0 |
HIP 80434 |
21.90 |
| 2026-08-18 00:00 |
16:24:57.47 |
+31:21:41.1 |
HIP 80434 |
22.87 |
| 2026-08-18 12:00 |
16:24:57.38 |
+31:20:43.1 |
HIP 80434 |
23.83 |
| 2026-08-19 00:00 |
16:24:57.34 |
+31:19:44.9 |
HIP 80434 |
24.80 |