| Parameter |
Value |
| Designation |
C/2016 A1 (PANSTARRS) |
| Type |
C |
| Perihelion (tp_cal, UTC) |
2017-11-23T08:54:05.518080Z |
| Orbit solution date (soln_date, UTC) |
2022-07-19T01:12:15Z |
| Obs used |
2143 |
| NEO |
- |
| M1 |
6.400 |
| K1 |
9.250 |
| PC |
0.030 |
Osculating Elements
| Parameter |
Value |
| Epoch (epoch_cal, TDB) |
2017-11-13.0000000 |
| e |
1.00196775 |
| q (au) |
5.327762 |
| a (au) |
-2707.536844 |
| i (deg) |
121.185405 |
| Ω (om, deg) |
128.174457 |
| ω (w, deg) |
10.320070 |
| M (ma, deg) |
-0.000073 |
Magnitude
Scatter + Global Linear
$$
M_a = (5.402 + 3.724\cdot 2.5\log_{10} r) + \epsilon - 2.5\log_{10}\Phi(\theta) + 5\log_{10}\Delta
$$
$$
\theta = 180^\circ - \alpha
$$
$$
\Phi(\theta) = \frac{\delta_{90} D(\theta) + 1}{\delta_{90} + 1},\quad D(\theta) = k\cdot \Phi_{HG}(\theta; g_f) + (1-k)\cdot \Phi_{HG}(\theta; g_b)
$$
$$
\Phi_{HG}(\theta; g) = \left(\frac{1+g^2}{1+g^2-2g\cos\theta}\right)^{3/2},\quad \Phi_{HG}(90^\circ)=1
$$
Model Parameters
| Parameter |
Value |
| H0 |
5.402 |
| n |
3.724 |
| gf |
1.000 |
| gb |
-1.000 |
| 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 |
| 2016-01-01 |
2017-11-22 |
-2.3519 |
+1.891 |
| 2017-11-26 |
2019-03-10 |
-2.2345 |
+1.488 |
| 2019-03-10 |
2020-02-15 |
+16.2456 |
-13.536 |
log10 r = log10(heliocentric distance / AU), Δ = geocentric distance (AU)
Ephemeris
| Date/Time (UTC) |
RA (J2000) |
Dec (J2000) |
Nearest HIP |
Dist from HIP (arcmin) |
| 2026-03-26 00:00 |
21:52:43.89 |
+31:53:45.1 |
HIP 107904 |
12.65 |
| 2026-03-26 12:00 |
21:52:48.61 |
+31:54:27.2 |
HIP 107904 |
13.61 |
| 2026-03-27 00:00 |
21:52:53.30 |
+31:55:09.6 |
HIP 107904 |
14.61 |
| 2026-03-27 12:00 |
21:52:57.95 |
+31:55:52.3 |
HIP 107904 |
15.63 |
| 2026-03-28 00:00 |
21:53:02.57 |
+31:56:35.3 |
HIP 107904 |
16.67 |
| 2026-03-28 12:00 |
21:53:07.15 |
+31:57:18.6 |
HIP 107904 |
17.73 |
| 2026-03-29 00:00 |
21:53:11.69 |
+31:58:02.1 |
HIP 107904 |
18.79 |
| 2026-03-29 12:00 |
21:53:16.19 |
+31:58:45.9 |
HIP 107904 |
19.87 |
| 2026-03-30 00:00 |
21:53:20.66 |
+31:59:30.0 |
HIP 107904 |
20.95 |
| 2026-03-30 12:00 |
21:53:25.10 |
+32:00:14.3 |
HIP 107904 |
22.04 |
| 2026-03-31 00:00 |
21:53:29.49 |
+32:00:58.9 |
HIP 107904 |
23.13 |
| 2026-03-31 12:00 |
21:53:33.84 |
+32:01:43.8 |
HIP 108156 |
23.47 |
| 2026-04-01 00:00 |
21:53:38.16 |
+32:02:28.8 |
HIP 108156 |
22.31 |
| 2026-04-01 12:00 |
21:53:42.44 |
+32:03:14.2 |
HIP 108156 |
21.15 |
| 2026-04-02 00:00 |
21:53:46.68 |
+32:03:59.8 |
HIP 108156 |
20.00 |
| 2026-04-02 12:00 |
21:53:50.88 |
+32:04:45.6 |
HIP 108156 |
18.85 |
| 2026-04-03 00:00 |
21:53:55.04 |
+32:05:31.6 |
HIP 108156 |
17.70 |
| 2026-04-03 12:00 |
21:53:59.16 |
+32:06:17.9 |
HIP 108156 |
16.57 |
| 2026-04-04 00:00 |
21:54:03.25 |
+32:07:04.4 |
HIP 108156 |
15.43 |
| 2026-04-04 12:00 |
21:54:07.29 |
+32:07:51.1 |
HIP 108156 |
14.31 |
| 2026-04-05 00:00 |
21:54:11.29 |
+32:08:38.1 |
HIP 108156 |
13.19 |
| 2026-04-05 12:00 |
21:54:15.25 |
+32:09:25.3 |
HIP 108156 |
12.08 |
| 2026-04-06 00:00 |
21:54:19.17 |
+32:10:12.7 |
HIP 108156 |
10.98 |
| 2026-04-06 12:00 |
21:54:23.05 |
+32:11:00.2 |
HIP 108156 |
9.89 |
| 2026-04-07 00:00 |
21:54:26.88 |
+32:11:48.0 |
HIP 108156 |
8.81 |
| 2026-04-07 12:00 |
21:54:30.67 |
+32:12:36.0 |
HIP 108156 |
7.75 |
| 2026-04-08 00:00 |
21:54:34.43 |
+32:13:24.2 |
HIP 108156 |
6.72 |
| 2026-04-08 12:00 |
21:54:38.13 |
+32:14:12.6 |
HIP 108156 |
5.72 |
| 2026-04-09 00:00 |
21:54:41.80 |
+32:15:01.2 |
HIP 108156 |
4.77 |
| 2026-04-09 12:00 |
21:54:45.42 |
+32:15:50.0 |
HIP 108156 |
3.92 |
| 2026-04-10 00:00 |
21:54:49.00 |
+32:16:38.9 |
HIP 108156 |
3.22 |
| 2026-04-10 12:00 |
21:54:52.54 |
+32:17:28.1 |
HIP 108156 |
2.79 |
| 2026-04-11 00:00 |
21:54:56.03 |
+32:18:17.4 |
HIP 108167 |
2.06 |
| 2026-04-11 12:00 |
21:54:59.47 |
+32:19:06.8 |
HIP 108167 |
1.62 |
| 2026-04-12 00:00 |
21:55:02.87 |
+32:19:56.5 |
HIP 108167 |
1.84 |
| 2026-04-12 12:00 |
21:55:06.23 |
+32:20:46.3 |
HIP 108167 |
2.54 |
| 2026-04-13 00:00 |
21:55:09.54 |
+32:21:36.2 |
HIP 108167 |
3.45 |
| 2026-04-13 12:00 |
21:55:12.81 |
+32:22:26.4 |
HIP 108167 |
4.43 |
| 2026-04-14 00:00 |
21:55:16.03 |
+32:23:16.6 |
HIP 108167 |
5.44 |
| 2026-04-14 12:00 |
21:55:19.20 |
+32:24:07.0 |
HIP 108167 |
6.47 |
| 2026-04-15 00:00 |
21:55:22.33 |
+32:24:57.6 |
HIP 108167 |
7.50 |
| 2026-04-15 12:00 |
21:55:25.41 |
+32:25:48.3 |
HIP 108167 |
8.54 |
| 2026-04-16 00:00 |
21:55:28.44 |
+32:26:39.1 |
HIP 108167 |
9.58 |