| 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) |
| 2026-03-26 00:00 |
16:03:52.76 |
+01:20:27.1 |
HIP 78610 |
25.56 |
| 2026-03-26 12:00 |
16:03:49.14 |
+01:21:04.5 |
HIP 78610 |
24.55 |
| 2026-03-27 00:00 |
16:03:45.46 |
+01:21:41.9 |
HIP 78610 |
23.54 |
| 2026-03-27 12:00 |
16:03:41.72 |
+01:22:19.2 |
HIP 78610 |
22.53 |
| 2026-03-28 00:00 |
16:03:37.91 |
+01:22:56.5 |
HIP 78610 |
21.53 |
| 2026-03-28 12:00 |
16:03:34.05 |
+01:23:33.8 |
HIP 78610 |
20.53 |
| 2026-03-29 00:00 |
16:03:30.12 |
+01:24:10.9 |
HIP 78610 |
19.55 |
| 2026-03-29 12:00 |
16:03:26.13 |
+01:24:48.1 |
HIP 78610 |
18.58 |
| 2026-03-30 00:00 |
16:03:22.09 |
+01:25:25.2 |
HIP 78610 |
17.63 |
| 2026-03-30 12:00 |
16:03:17.98 |
+01:26:02.2 |
HIP 78610 |
16.70 |
| 2026-03-31 00:00 |
16:03:13.81 |
+01:26:39.1 |
HIP 78610 |
15.81 |
| 2026-03-31 12:00 |
16:03:09.58 |
+01:27:16.0 |
HIP 78610 |
14.97 |
| 2026-04-01 00:00 |
16:03:05.30 |
+01:27:52.8 |
HIP 78610 |
14.18 |
| 2026-04-01 12:00 |
16:03:00.95 |
+01:28:29.6 |
HIP 78610 |
13.45 |
| 2026-04-02 00:00 |
16:02:56.55 |
+01:29:06.2 |
HIP 78610 |
12.81 |
| 2026-04-02 12:00 |
16:02:52.09 |
+01:29:42.8 |
HIP 78610 |
12.26 |
| 2026-04-03 00:00 |
16:02:47.57 |
+01:30:19.3 |
HIP 78610 |
11.83 |
| 2026-04-03 12:00 |
16:02:43.00 |
+01:30:55.7 |
HIP 78610 |
11.54 |
| 2026-04-04 00:00 |
16:02:38.36 |
+01:31:31.9 |
HIP 78610 |
11.39 |
| 2026-04-04 12:00 |
16:02:33.68 |
+01:32:08.1 |
HIP 78610 |
11.40 |
| 2026-04-05 00:00 |
16:02:28.93 |
+01:32:44.2 |
HIP 78610 |
11.57 |
| 2026-04-05 12:00 |
16:02:24.13 |
+01:33:20.2 |
HIP 78610 |
11.90 |
| 2026-04-06 00:00 |
16:02:19.28 |
+01:33:56.0 |
HIP 78610 |
12.38 |
| 2026-04-06 12:00 |
16:02:14.37 |
+01:34:31.8 |
HIP 78610 |
12.99 |
| 2026-04-07 00:00 |
16:02:09.40 |
+01:35:07.4 |
HIP 78610 |
13.73 |
| 2026-04-07 12:00 |
16:02:04.39 |
+01:35:42.9 |
HIP 78610 |
14.57 |
| 2026-04-08 00:00 |
16:01:59.31 |
+01:36:18.3 |
HIP 78610 |
15.50 |
| 2026-04-08 12:00 |
16:01:54.19 |
+01:36:53.5 |
HIP 78610 |
16.51 |
| 2026-04-09 00:00 |
16:01:49.01 |
+01:37:28.6 |
HIP 78610 |
17.60 |
| 2026-04-09 12:00 |
16:01:43.78 |
+01:38:03.5 |
HIP 78610 |
18.73 |
| 2026-04-10 00:00 |
16:01:38.50 |
+01:38:38.3 |
HIP 78610 |
19.92 |
| 2026-04-10 12:00 |
16:01:33.17 |
+01:39:13.0 |
HIP 78610 |
21.16 |
| 2026-04-11 00:00 |
16:01:27.79 |
+01:39:47.5 |
HIP 78610 |
22.43 |
| 2026-04-11 12:00 |
16:01:22.35 |
+01:40:21.8 |
HIP 78498 |
23.55 |
| 2026-04-12 00:00 |
16:01:16.87 |
+01:40:56.0 |
HIP 78498 |
23.11 |
| 2026-04-12 12:00 |
16:01:11.33 |
+01:41:30.0 |
HIP 78498 |
22.77 |
| 2026-04-13 00:00 |
16:01:05.75 |
+01:42:03.8 |
HIP 78498 |
22.53 |
| 2026-04-13 12:00 |
16:01:00.12 |
+01:42:37.5 |
HIP 78498 |
22.40 |
| 2026-04-14 00:00 |
16:00:54.44 |
+01:43:11.0 |
HIP 78498 |
22.37 |
| 2026-04-14 12:00 |
16:00:48.72 |
+01:43:44.3 |
HIP 78498 |
22.46 |
| 2026-04-15 00:00 |
16:00:42.94 |
+01:44:17.4 |
HIP 78498 |
22.66 |
| 2026-04-15 12:00 |
16:00:37.12 |
+01:44:50.3 |
HIP 78498 |
22.97 |
| 2026-04-16 00:00 |
16:00:31.26 |
+01:45:23.0 |
HIP 78498 |
23.38 |