| Parameter |
Value |
| Designation |
C/2018 F4 (PANSTARRS) |
| Type |
C |
| Perihelion (tp_cal, UTC) |
2019-12-04T01:26:15.930240Z |
| Orbit solution date (soln_date, UTC) |
2023-04-24T19:06:39Z |
| Obs used |
530 |
| NEO |
- |
| M1 |
5.300 |
| K1 |
13.250 |
| PC |
0.030 |
| Discovery observation (MPC, UTC) |
2018-03-17T12:40:26.976000Z |
| Discovery magnitude (MPC) |
20.40 w |
| Discovery observatory (MPC) |
F51 · Pan-STARRS 1, Haleakala |
Osculating Elements
| Parameter |
Value |
| Epoch (epoch_cal, TDB) |
2019-09-20.0000000 |
| e |
1.00152144 |
| q (au) |
3.439968 |
| a (au) |
-2260.993631 |
| i (deg) |
78.098889 |
| Ω (om, deg) |
26.507082 |
| ω (w, deg) |
263.204195 |
| M (ma, deg) |
-0.000688 |
Magnitude
Scatter + Global Linear
$$
M_a = (5.479 + 6.000\cdot 2.5\log_{10} r) + \epsilon - 2.5\log_{10}\Phi(\theta) + 5\log_{10}\Delta
$$
$$
\theta = 180^\circ - \alpha
$$
$$
\Phi(\theta) = \frac{\delta_{90} D(\theta) + 1}{\delta_{90} + 1},\quad D(\theta) = k\cdot \Phi_{HG}(\theta; g_f) + (1-k)\cdot \Phi_{HG}(\theta; g_b)
$$
$$
\Phi_{HG}(\theta; g) = \left(\frac{1+g^2}{1+g^2-2g\cos\theta}\right)^{3/2},\quad \Phi_{HG}(90^\circ)=1
$$
Model Parameters
| Parameter |
Value |
| H0 |
5.479 |
| n |
6.000 |
| gf |
1.000 |
| gb |
-0.616 |
| k |
0.800 |
| 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 |
| 2018-03-17 |
2019-12-03 |
-4.5179 |
+3.714 |
| 2019-12-04 |
2020-09-08 |
+3.2670 |
-2.149 |
| 2020-09-08 |
2021-01-03 |
+3.3546 |
-2.816 |
| 2021-01-03 |
2021-11-06 |
+2.1461 |
-1.581 |
log10 r = log10(heliocentric distance / AU), Δ = geocentric distance (AU)
Ephemeris
| Date/Time (UTC) |
RA (J2000) |
Dec (J2000) |
Nearest HIP |
Dist from HIP (arcmin) |
| 2026-09-20 00:00 |
01:20:38.50 |
+42:14:13.7 |
HIP 6241 |
17.16 |
| 2026-09-20 12:00 |
01:20:30.07 |
+42:14:22.1 |
HIP 6241 |
16.79 |
| 2026-09-21 00:00 |
01:20:21.60 |
+42:14:29.9 |
HIP 6241 |
16.55 |
| 2026-09-21 12:00 |
01:20:13.11 |
+42:14:37.0 |
HIP 6241 |
16.45 |
| 2026-09-22 00:00 |
01:20:04.58 |
+42:14:43.6 |
HIP 6241 |
16.49 |
| 2026-09-22 12:00 |
01:19:56.02 |
+42:14:49.5 |
HIP 6241 |
16.67 |
| 2026-09-23 00:00 |
01:19:47.43 |
+42:14:54.8 |
HIP 6241 |
16.99 |
| 2026-09-23 12:00 |
01:19:38.81 |
+42:14:59.5 |
HIP 6241 |
17.44 |
| 2026-09-24 00:00 |
01:19:30.16 |
+42:15:03.6 |
HIP 6241 |
18.01 |
| 2026-09-24 12:00 |
01:19:21.48 |
+42:15:07.1 |
HIP 6241 |
18.70 |
| 2026-09-25 00:00 |
01:19:12.77 |
+42:15:10.0 |
HIP 6241 |
19.49 |
| 2026-09-25 12:00 |
01:19:04.04 |
+42:15:12.3 |
HIP 6241 |
20.38 |
| 2026-09-26 00:00 |
01:18:55.28 |
+42:15:13.9 |
HIP 6241 |
21.34 |
| 2026-09-26 12:00 |
01:18:46.49 |
+42:15:15.0 |
HIP 6241 |
22.38 |
| 2026-09-27 00:00 |
01:18:37.68 |
+42:15:15.4 |
HIP 6241 |
23.48 |
| 2026-09-27 12:00 |
01:18:28.85 |
+42:15:15.2 |
HIP 6241 |
24.63 |
| 2026-09-28 00:00 |
01:18:19.99 |
+42:15:14.4 |
HIP 6241 |
25.84 |
| 2026-09-28 12:00 |
01:18:11.11 |
+42:15:13.0 |
HIP 6241 |
27.08 |
| 2026-09-29 00:00 |
01:18:02.21 |
+42:15:11.0 |
HIP 6241 |
28.37 |
| 2026-09-29 12:00 |
01:17:53.28 |
+42:15:08.4 |
HIP 6241 |
29.69 |
| 2026-09-30 00:00 |
01:17:44.34 |
+42:15:05.2 |
HIP 6241 |
31.04 |
| 2026-09-30 12:00 |
01:17:35.37 |
+42:15:01.4 |
HIP 6241 |
32.41 |
| 2026-10-01 00:00 |
01:17:26.39 |
+42:14:56.9 |
HIP 6241 |
33.81 |
| 2026-10-01 12:00 |
01:17:17.38 |
+42:14:51.9 |
HIP 6241 |
35.24 |
| 2026-10-02 00:00 |
01:17:08.36 |
+42:14:46.2 |
HIP 6241 |
36.68 |
| 2026-10-02 12:00 |
01:16:59.33 |
+42:14:39.9 |
HIP 6241 |
38.14 |
| 2026-10-03 00:00 |
01:16:50.27 |
+42:14:33.1 |
HIP 6241 |
39.61 |
| 2026-10-03 12:00 |
01:16:41.20 |
+42:14:25.6 |
HIP 6241 |
41.10 |
| 2026-10-04 00:00 |
01:16:32.12 |
+42:14:17.5 |
HIP 5944 |
42.08 |
| 2026-10-04 12:00 |
01:16:23.02 |
+42:14:08.8 |
HIP 5944 |
42.24 |
| 2026-10-05 00:00 |
01:16:13.91 |
+42:13:59.6 |
HIP 5944 |
42.47 |
| 2026-10-05 12:00 |
01:16:04.79 |
+42:13:49.7 |
HIP 5944 |
42.78 |
| 2026-10-06 00:00 |
01:15:55.66 |
+42:13:39.2 |
HIP 5944 |
43.16 |
| 2026-10-06 12:00 |
01:15:46.51 |
+42:13:28.1 |
HIP 5606 |
43.02 |
| 2026-10-07 00:00 |
01:15:37.36 |
+42:13:16.4 |
HIP 5606 |
41.33 |
| 2026-10-07 12:00 |
01:15:28.20 |
+42:13:04.1 |
HIP 5606 |
39.63 |
| 2026-10-08 00:00 |
01:15:19.03 |
+42:12:51.3 |
HIP 5606 |
37.94 |
| 2026-10-08 12:00 |
01:15:09.85 |
+42:12:37.8 |
HIP 5606 |
36.25 |
| 2026-10-09 00:00 |
01:15:00.66 |
+42:12:23.7 |
HIP 5606 |
34.56 |
| 2026-10-09 12:00 |
01:14:51.48 |
+42:12:09.1 |
HIP 5606 |
32.87 |
| 2026-10-10 00:00 |
01:14:42.28 |
+42:11:53.9 |
HIP 5606 |
31.18 |
| 2026-10-10 12:00 |
01:14:33.09 |
+42:11:38.1 |
HIP 5606 |
29.50 |
| 2026-10-11 00:00 |
01:14:23.89 |
+42:11:21.7 |
HIP 5606 |
27.82 |