C/2018 R4 (Fuls)
| Parameter |
Value |
| Designation |
C/2018 R4 (Fuls) |
| Type |
C |
| Perihelion (tp_cal, UTC) |
2018-03-03T15:59:10.642560Z |
| Orbit solution date (soln_date, UTC) |
2022-06-20T23:12:32Z |
| Obs used |
114 |
| NEO |
- |
| M1 |
16.300 |
| K1 |
4.500 |
| PC |
- |
| Discovery observation (MPC, UTC) |
2018-09-09T07:28:08.544000Z |
| Discovery magnitude (MPC) |
19.10 G |
| Discovery observatory (MPC) |
703 · Catalina Sky Survey |
Osculating Elements
| Parameter |
Value |
| Epoch (epoch_cal, TDB) |
2018-09-02.0000000 |
| e |
0.99435878 |
| q (au) |
1.709214 |
| a (au) |
302.986704 |
| i (deg) |
11.682034 |
| Ω (om, deg) |
298.460925 |
| ω (w, deg) |
345.148323 |
| M (ma, deg) |
0.034075 |
Magnitude
Scatter + Global Linear
$$
M_a = (16.140 + 3.866\cdot 2.5\log_{10} r) + \epsilon - 2.5\log_{10}\Phi(\theta) + 5\log_{10}\Delta
$$
$$
\theta = 180^\circ - \alpha
$$
$$
\Phi(\theta) = \frac{\delta_{90} D(\theta) + 1}{\delta_{90} + 1},\quad D(\theta) = k\cdot \Phi_{HG}(\theta; g_f) + (1-k)\cdot \Phi_{HG}(\theta; g_b)
$$
$$
\Phi_{HG}(\theta; g) = \left(\frac{1+g^2}{1+g^2-2g\cos\theta}\right)^{3/2},\quad \Phi_{HG}(90^\circ)=1
$$
Model Parameters
| Parameter |
Value |
| H0 |
16.140 |
| n |
3.866 |
| gf |
1.000 |
| gb |
-0.685 |
| 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
Ephemeris
| Date/Time (UTC) |
RA (J2000) |
Dec (J2000) |
Nearest HIP |
Dist from HIP (arcmin) |
| 2026-02-03 00:00 |
04:22:04.78 |
+30:27:51.5 |
HIP 20415 |
4.19 |
| 2026-02-03 12:00 |
04:22:02.74 |
+30:27:33.3 |
HIP 20415 |
4.40 |
| 2026-02-04 00:00 |
04:22:00.75 |
+30:27:15.3 |
HIP 20415 |
4.65 |
| 2026-02-04 12:00 |
04:21:58.82 |
+30:26:57.4 |
HIP 20415 |
4.94 |
| 2026-02-05 00:00 |
04:21:56.95 |
+30:26:39.5 |
HIP 20415 |
5.25 |
| 2026-02-05 12:00 |
04:21:55.13 |
+30:26:21.7 |
HIP 20415 |
5.57 |
| 2026-02-06 00:00 |
04:21:53.37 |
+30:26:04.1 |
HIP 20415 |
5.91 |
| 2026-02-06 12:00 |
04:21:51.67 |
+30:25:46.5 |
HIP 20415 |
6.25 |
| 2026-02-07 00:00 |
04:21:50.02 |
+30:25:29.0 |
HIP 20415 |
6.60 |
| 2026-02-07 12:00 |
04:21:48.44 |
+30:25:11.6 |
HIP 20415 |
6.95 |
| 2026-02-08 00:00 |
04:21:46.91 |
+30:24:54.3 |
HIP 20415 |
7.29 |
| 2026-02-08 12:00 |
04:21:45.43 |
+30:24:37.1 |
HIP 20415 |
7.63 |
| 2026-02-09 00:00 |
04:21:44.02 |
+30:24:20.0 |
HIP 20415 |
7.97 |
| 2026-02-09 12:00 |
04:21:42.66 |
+30:24:03.0 |
HIP 20415 |
8.30 |
| 2026-02-10 00:00 |
04:21:41.36 |
+30:23:46.1 |
HIP 20415 |
8.63 |
| 2026-02-10 12:00 |
04:21:40.11 |
+30:23:29.3 |
HIP 20415 |
8.95 |
| 2026-02-11 00:00 |
04:21:38.93 |
+30:23:12.6 |
HIP 20415 |
9.26 |
| 2026-02-11 12:00 |
04:21:37.80 |
+30:22:56.0 |
HIP 20415 |
9.57 |
| 2026-02-12 00:00 |
04:21:36.73 |
+30:22:39.5 |
HIP 20415 |
9.87 |
| 2026-02-12 12:00 |
04:21:35.72 |
+30:22:23.2 |
HIP 20415 |
10.15 |
| 2026-02-13 00:00 |
04:21:34.77 |
+30:22:06.9 |
HIP 20415 |
10.43 |
| 2026-02-13 12:00 |
04:21:33.88 |
+30:21:50.8 |
HIP 20415 |
10.70 |
| 2026-02-14 00:00 |
04:21:33.04 |
+30:21:34.7 |
HIP 20415 |
10.97 |
| 2026-02-14 12:00 |
04:21:32.26 |
+30:21:18.8 |
HIP 20415 |
11.22 |
| 2026-02-15 00:00 |
04:21:31.54 |
+30:21:03.0 |
HIP 20415 |
11.46 |
| 2026-02-15 12:00 |
04:21:30.88 |
+30:20:47.3 |
HIP 20415 |
11.69 |
| 2026-02-16 00:00 |
04:21:30.28 |
+30:20:31.8 |
HIP 20415 |
11.92 |
| 2026-02-16 12:00 |
04:21:29.73 |
+30:20:16.3 |
HIP 20415 |
12.13 |
| 2026-02-17 00:00 |
04:21:29.24 |
+30:20:01.0 |
HIP 20415 |
12.34 |
| 2026-02-17 12:00 |
04:21:28.81 |
+30:19:45.8 |
HIP 20415 |
12.54 |
| 2026-02-18 00:00 |
04:21:28.44 |
+30:19:30.7 |
HIP 20415 |
12.72 |
| 2026-02-18 12:00 |
04:21:28.13 |
+30:19:15.8 |
HIP 20415 |
12.90 |
| 2026-02-19 00:00 |
04:21:27.88 |
+30:19:00.9 |
HIP 20415 |
13.07 |
| 2026-02-19 12:00 |
04:21:27.68 |
+30:18:46.2 |
HIP 20415 |
13.23 |
| 2026-02-20 00:00 |
04:21:27.54 |
+30:18:31.6 |
HIP 20415 |
13.38 |
| 2026-02-20 12:00 |
04:21:27.46 |
+30:18:17.2 |
HIP 20415 |
13.52 |
| 2026-02-21 00:00 |
04:21:27.44 |
+30:18:02.9 |
HIP 20415 |
13.65 |
| 2026-02-21 12:00 |
04:21:27.47 |
+30:17:48.7 |
HIP 20415 |
13.77 |
| 2026-02-22 00:00 |
04:21:27.57 |
+30:17:34.6 |
HIP 20415 |
13.89 |
| 2026-02-22 12:00 |
04:21:27.72 |
+30:17:20.7 |
HIP 20415 |
13.99 |
| 2026-02-23 00:00 |
04:21:27.93 |
+30:17:06.9 |
HIP 20415 |
14.09 |
| 2026-02-23 12:00 |
04:21:28.19 |
+30:16:53.2 |
HIP 20415 |
14.18 |
| 2026-02-24 00:00 |
04:21:28.51 |
+30:16:39.7 |
HIP 20415 |
14.27 |