| 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) |
| 2026-05-12 00:00 |
15:54:38.75 |
+02:07:36.4 |
HIP 77897 |
2.99 |
| 2026-05-12 12:00 |
15:54:31.36 |
+02:07:53.4 |
HIP 77897 |
1.19 |
| 2026-05-13 00:00 |
15:54:23.96 |
+02:08:10.1 |
HIP 77897 |
0.94 |
| 2026-05-13 12:00 |
15:54:16.55 |
+02:08:26.4 |
HIP 77897 |
2.71 |
| 2026-05-14 00:00 |
15:54:09.14 |
+02:08:42.3 |
HIP 77897 |
4.56 |
| 2026-05-14 12:00 |
15:54:01.71 |
+02:08:57.8 |
HIP 77897 |
6.43 |
| 2026-05-15 00:00 |
15:53:54.27 |
+02:09:12.9 |
HIP 77897 |
8.30 |
| 2026-05-15 12:00 |
15:53:46.83 |
+02:09:27.7 |
HIP 77897 |
10.17 |
| 2026-05-16 00:00 |
15:53:39.38 |
+02:09:42.0 |
HIP 77897 |
12.05 |
| 2026-05-16 12:00 |
15:53:31.93 |
+02:09:56.0 |
HIP 77897 |
13.92 |
| 2026-05-17 00:00 |
15:53:24.47 |
+02:10:09.5 |
HIP 77897 |
15.80 |
| 2026-05-17 12:00 |
15:53:17.00 |
+02:10:22.7 |
HIP 77897 |
17.68 |
| 2026-05-18 00:00 |
15:53:09.53 |
+02:10:35.4 |
HIP 77897 |
19.55 |
| 2026-05-18 12:00 |
15:53:02.06 |
+02:10:47.8 |
HIP 77897 |
21.43 |
| 2026-05-19 00:00 |
15:52:54.59 |
+02:10:59.7 |
HIP 77897 |
23.31 |
| 2026-05-19 12:00 |
15:52:47.11 |
+02:11:11.3 |
HIP 77897 |
25.19 |
| 2026-05-20 00:00 |
15:52:39.64 |
+02:11:22.4 |
HIP 77897 |
27.06 |
| 2026-05-20 12:00 |
15:52:32.16 |
+02:11:33.1 |
HIP 77897 |
28.94 |
| 2026-05-21 00:00 |
15:52:24.69 |
+02:11:43.4 |
HIP 77897 |
30.81 |
| 2026-05-21 12:00 |
15:52:17.22 |
+02:11:53.3 |
HIP 77578 |
29.90 |
| 2026-05-22 00:00 |
15:52:09.75 |
+02:12:02.7 |
HIP 77578 |
28.04 |
| 2026-05-22 12:00 |
15:52:02.28 |
+02:12:11.8 |
HIP 77578 |
26.17 |
| 2026-05-23 00:00 |
15:51:54.82 |
+02:12:20.4 |
HIP 77578 |
24.31 |
| 2026-05-23 12:00 |
15:51:47.36 |
+02:12:28.6 |
HIP 77578 |
22.45 |
| 2026-05-24 00:00 |
15:51:39.91 |
+02:12:36.4 |
HIP 77578 |
20.60 |
| 2026-05-24 12:00 |
15:51:32.46 |
+02:12:43.7 |
HIP 77578 |
18.74 |
| 2026-05-25 00:00 |
15:51:25.02 |
+02:12:50.7 |
HIP 77578 |
16.89 |
| 2026-05-25 12:00 |
15:51:17.59 |
+02:12:57.2 |
HIP 77578 |
15.05 |
| 2026-05-26 00:00 |
15:51:10.17 |
+02:13:03.3 |
HIP 77578 |
13.21 |
| 2026-05-26 12:00 |
15:51:02.75 |
+02:13:09.0 |
HIP 77578 |
11.38 |
| 2026-05-27 00:00 |
15:50:55.34 |
+02:13:14.2 |
HIP 77578 |
9.56 |
| 2026-05-27 12:00 |
15:50:47.95 |
+02:13:19.0 |
HIP 77578 |
7.75 |
| 2026-05-28 00:00 |
15:50:40.56 |
+02:13:23.4 |
HIP 77578 |
5.97 |
| 2026-05-28 12:00 |
15:50:33.19 |
+02:13:27.3 |
HIP 77578 |
4.25 |
| 2026-05-29 00:00 |
15:50:25.82 |
+02:13:30.8 |
HIP 77578 |
2.69 |
| 2026-05-29 12:00 |
15:50:18.47 |
+02:13:33.9 |
HIP 77578 |
1.78 |
| 2026-05-30 00:00 |
15:50:11.13 |
+02:13:36.6 |
HIP 77578 |
2.42 |
| 2026-05-30 12:00 |
15:50:03.81 |
+02:13:38.8 |
HIP 77578 |
3.89 |
| 2026-05-31 00:00 |
15:49:56.50 |
+02:13:40.6 |
HIP 77578 |
5.58 |
| 2026-05-31 12:00 |
15:49:49.21 |
+02:13:41.9 |
HIP 77578 |
7.33 |
| 2026-06-01 00:00 |
15:49:41.93 |
+02:13:42.9 |
HIP 77578 |
9.10 |
| 2026-06-01 12:00 |
15:49:34.67 |
+02:13:43.3 |
HIP 77578 |
10.88 |
| 2026-06-02 00:00 |
15:49:27.42 |
+02:13:43.4 |
HIP 77578 |
12.66 |