C/2018 X3 (PANSTARRS)
| Parameter |
Value |
| Designation |
C/2018 X3 (PANSTARRS) |
| Type |
C |
| Perihelion (tp_cal, UTC) |
2018-12-30T19:11:56.958720Z |
| Orbit solution date (soln_date, UTC) |
2021-04-15T23:33:48Z |
| Obs used |
50 |
| NEO |
- |
| M1 |
16.900 |
| K1 |
4.500 |
| PC |
- |
| Discovery observation (MPC, UTC) |
2018-12-12T11:04:53.472000Z |
| Discovery magnitude (MPC) |
20.50 w |
| Discovery observatory (MPC) |
F51 · Pan-STARRS 1, Haleakala |
Osculating Elements
| Parameter |
Value |
| Epoch (epoch_cal, TDB) |
2018-12-10.0000000 |
| e |
0.78271953 |
| q (au) |
2.698917 |
| a (au) |
12.421353 |
| i (deg) |
43.369641 |
| Ω (om, deg) |
78.924758 |
| ω (w, deg) |
359.834482 |
| M (ma, deg) |
359.531712 |
Magnitude
Scatter + Global Linear
$$
M_a = (16.711 + 2.000\cdot 2.5\log_{10} r) + \epsilon - 2.5\log_{10}\Phi(\theta) + 5\log_{10}\Delta
$$
$$
\theta = 180^\circ - \alpha
$$
$$
\Phi(\theta) = \frac{\delta_{90} D(\theta) + 1}{\delta_{90} + 1},\quad D(\theta) = k\cdot \Phi_{HG}(\theta; g_f) + (1-k)\cdot \Phi_{HG}(\theta; g_b)
$$
$$
\Phi_{HG}(\theta; g) = \left(\frac{1+g^2}{1+g^2-2g\cos\theta}\right)^{3/2},\quad \Phi_{HG}(90^\circ)=1
$$
Model Parameters
| Parameter |
Value |
| H0 |
16.711 |
| n |
2.000 |
| gf |
0.800 |
| gb |
-0.500 |
| k |
0.943 |
| δ90 |
1.000 |
| 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) |
| 2026-02-03 00:00 |
16:04:03.75 |
+00:26:16.0 |
HIP 78742 |
15.49 |
| 2026-02-03 12:00 |
16:04:07.08 |
+00:26:36.4 |
HIP 78742 |
14.85 |
| 2026-02-04 00:00 |
16:04:10.34 |
+00:26:57.1 |
HIP 78742 |
14.23 |
| 2026-02-04 12:00 |
16:04:13.55 |
+00:27:18.2 |
HIP 78742 |
13.64 |
| 2026-02-05 00:00 |
16:04:16.69 |
+00:27:39.6 |
HIP 78742 |
13.09 |
| 2026-02-05 12:00 |
16:04:19.77 |
+00:28:01.2 |
HIP 78742 |
12.57 |
| 2026-02-06 00:00 |
16:04:22.78 |
+00:28:23.2 |
HIP 78742 |
12.08 |
| 2026-02-06 12:00 |
16:04:25.73 |
+00:28:45.6 |
HIP 78742 |
11.63 |
| 2026-02-07 00:00 |
16:04:28.61 |
+00:29:08.2 |
HIP 78742 |
11.21 |
| 2026-02-07 12:00 |
16:04:31.43 |
+00:29:31.1 |
HIP 78742 |
10.84 |
| 2026-02-08 00:00 |
16:04:34.18 |
+00:29:54.4 |
HIP 78742 |
10.50 |
| 2026-02-08 12:00 |
16:04:36.87 |
+00:30:17.9 |
HIP 78742 |
10.21 |
| 2026-02-09 00:00 |
16:04:39.49 |
+00:30:41.8 |
HIP 78742 |
9.96 |
| 2026-02-09 12:00 |
16:04:42.05 |
+00:31:05.9 |
HIP 78742 |
9.76 |
| 2026-02-10 00:00 |
16:04:44.54 |
+00:31:30.4 |
HIP 78742 |
9.60 |
| 2026-02-10 12:00 |
16:04:46.96 |
+00:31:55.1 |
HIP 78742 |
9.48 |
| 2026-02-11 00:00 |
16:04:49.32 |
+00:32:20.1 |
HIP 78742 |
9.41 |
| 2026-02-11 12:00 |
16:04:51.61 |
+00:32:45.4 |
HIP 78742 |
9.37 |
| 2026-02-12 00:00 |
16:04:53.83 |
+00:33:11.1 |
HIP 78742 |
9.38 |
| 2026-02-12 12:00 |
16:04:55.98 |
+00:33:36.9 |
HIP 78742 |
9.42 |
| 2026-02-13 00:00 |
16:04:58.07 |
+00:34:03.1 |
HIP 78742 |
9.50 |
| 2026-02-13 12:00 |
16:05:00.09 |
+00:34:29.6 |
HIP 78742 |
9.61 |
| 2026-02-14 00:00 |
16:05:02.04 |
+00:34:56.3 |
HIP 78742 |
9.75 |
| 2026-02-14 12:00 |
16:05:03.93 |
+00:35:23.3 |
HIP 78742 |
9.91 |
| 2026-02-15 00:00 |
16:05:05.74 |
+00:35:50.6 |
HIP 78742 |
10.10 |
| 2026-02-15 12:00 |
16:05:07.49 |
+00:36:18.1 |
HIP 78742 |
10.30 |
| 2026-02-16 00:00 |
16:05:09.16 |
+00:36:45.9 |
HIP 78742 |
10.52 |
| 2026-02-16 12:00 |
16:05:10.77 |
+00:37:14.0 |
HIP 78742 |
10.76 |
| 2026-02-17 00:00 |
16:05:12.31 |
+00:37:42.3 |
HIP 78742 |
11.00 |
| 2026-02-17 12:00 |
16:05:13.78 |
+00:38:10.9 |
HIP 78742 |
11.26 |
| 2026-02-18 00:00 |
16:05:15.18 |
+00:38:39.7 |
HIP 78742 |
11.52 |
| 2026-02-18 12:00 |
16:05:16.52 |
+00:39:08.8 |
HIP 78742 |
11.79 |
| 2026-02-19 00:00 |
16:05:17.78 |
+00:39:38.1 |
HIP 78742 |
12.07 |
| 2026-02-19 12:00 |
16:05:18.97 |
+00:40:07.6 |
HIP 78742 |
12.35 |
| 2026-02-20 00:00 |
16:05:20.09 |
+00:40:37.4 |
HIP 78742 |
12.63 |
| 2026-02-20 12:00 |
16:05:21.14 |
+00:41:07.5 |
HIP 78742 |
12.91 |
| 2026-02-21 00:00 |
16:05:22.13 |
+00:41:37.7 |
HIP 78742 |
13.20 |
| 2026-02-21 12:00 |
16:05:23.04 |
+00:42:08.2 |
HIP 78742 |
13.48 |
| 2026-02-22 00:00 |
16:05:23.88 |
+00:42:38.9 |
HIP 78742 |
13.77 |
| 2026-02-22 12:00 |
16:05:24.65 |
+00:43:09.9 |
HIP 78742 |
14.05 |
| 2026-02-23 00:00 |
16:05:25.35 |
+00:43:41.0 |
HIP 78742 |
14.33 |
| 2026-02-23 12:00 |
16:05:25.99 |
+00:44:12.4 |
HIP 78742 |
14.62 |
| 2026-02-24 00:00 |
16:05:26.55 |
+00:44:43.9 |
HIP 78742 |
14.90 |