| Parameter |
Value |
| Designation |
C/2018 F3 (Johnson) |
| Type |
C |
| Perihelion (tp_cal, UTC) |
2017-08-15T05:34:33.502080Z |
| Orbit solution date (soln_date, UTC) |
2021-04-15T23:33:43Z |
| Obs used |
51 |
| NEO |
- |
| M1 |
12.900 |
| K1 |
10.000 |
| PC |
- |
| Discovery observation (MPC, UTC) |
2018-03-20T06:23:56.832000Z |
| Discovery magnitude (MPC) |
19.40 G |
| Discovery observatory (MPC) |
G96 · University of Arizona Mt. Lemmon Survey |
Osculating Elements
| Parameter |
Value |
| Epoch (epoch_cal, TDB) |
2018-03-23.0000000 |
| e |
1.00001624 |
| q (au) |
2.483147 |
| a (au) |
-152892.693615 |
| i (deg) |
105.534913 |
| Ω (om, deg) |
173.031139 |
| ω (w, deg) |
293.010797 |
| M (ma, deg) |
0.000004 |
Magnitude
Scatter + Global Linear
$$
M_a = (14.744 + 2.000\cdot 2.5\log_{10} r) + \epsilon - 2.5\log_{10}\Phi(\theta) + 5\log_{10}\Delta
$$
$$
\theta = 180^\circ - \alpha
$$
$$
\Phi(\theta) = \frac{\delta_{90} D(\theta) + 1}{\delta_{90} + 1},\quad D(\theta) = k\cdot \Phi_{HG}(\theta; g_f) + (1-k)\cdot \Phi_{HG}(\theta; g_b)
$$
$$
\Phi_{HG}(\theta; g) = \left(\frac{1+g^2}{1+g^2-2g\cos\theta}\right)^{3/2},\quad \Phi_{HG}(90^\circ)=1
$$
Model Parameters
| Parameter |
Value |
| H0 |
14.744 |
| n |
2.000 |
| gf |
0.992 |
| gb |
-1.000 |
| k |
1.000 |
| δ90 |
9.995 |
| 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) |
| 2026-07-29 00:00 |
12:55:37.48 |
+73:56:21.0 |
HIP 62598 |
29.77 |
| 2026-07-29 12:00 |
12:55:44.64 |
+73:55:15.3 |
HIP 62598 |
30.81 |
| 2026-07-30 00:00 |
12:55:51.91 |
+73:54:09.7 |
HIP 62598 |
31.86 |
| 2026-07-30 12:00 |
12:55:59.29 |
+73:53:04.3 |
HIP 62598 |
32.93 |
| 2026-07-31 00:00 |
12:56:06.80 |
+73:51:59.1 |
HIP 62598 |
34.01 |
| 2026-07-31 12:00 |
12:56:14.42 |
+73:50:54.2 |
HIP 62598 |
35.11 |
| 2026-08-01 00:00 |
12:56:22.16 |
+73:49:49.4 |
HIP 62598 |
36.22 |
| 2026-08-01 12:00 |
12:56:30.01 |
+73:48:44.8 |
HIP 62598 |
37.33 |
| 2026-08-02 00:00 |
12:56:37.97 |
+73:47:40.5 |
HIP 62598 |
38.46 |
| 2026-08-02 12:00 |
12:56:46.05 |
+73:46:36.3 |
HIP 62598 |
39.60 |
| 2026-08-03 00:00 |
12:56:54.25 |
+73:45:32.4 |
HIP 62598 |
40.74 |
| 2026-08-03 12:00 |
12:57:02.55 |
+73:44:28.7 |
HIP 62598 |
41.89 |
| 2026-08-04 00:00 |
12:57:10.97 |
+73:43:25.2 |
HIP 62598 |
43.05 |
| 2026-08-04 12:00 |
12:57:19.50 |
+73:42:22.0 |
HIP 62598 |
44.22 |
| 2026-08-05 00:00 |
12:57:28.13 |
+73:41:19.0 |
HIP 63367 |
44.06 |
| 2026-08-05 12:00 |
12:57:36.88 |
+73:40:16.2 |
HIP 63367 |
42.93 |
| 2026-08-06 00:00 |
12:57:45.74 |
+73:39:13.7 |
HIP 63367 |
41.81 |
| 2026-08-06 12:00 |
12:57:54.70 |
+73:38:11.4 |
HIP 63367 |
40.70 |
| 2026-08-07 00:00 |
12:58:03.77 |
+73:37:09.3 |
HIP 63367 |
39.60 |
| 2026-08-07 12:00 |
12:58:12.95 |
+73:36:07.6 |
HIP 63367 |
38.51 |
| 2026-08-08 00:00 |
12:58:22.23 |
+73:35:06.0 |
HIP 63367 |
37.43 |
| 2026-08-08 12:00 |
12:58:31.62 |
+73:34:04.8 |
HIP 63367 |
36.37 |
| 2026-08-09 00:00 |
12:58:41.12 |
+73:33:03.8 |
HIP 63367 |
35.31 |
| 2026-08-09 12:00 |
12:58:50.72 |
+73:32:03.1 |
HIP 63367 |
34.28 |
| 2026-08-10 00:00 |
12:59:00.42 |
+73:31:02.6 |
HIP 63367 |
33.26 |
| 2026-08-10 12:00 |
12:59:10.22 |
+73:30:02.4 |
HIP 63367 |
32.26 |
| 2026-08-11 00:00 |
12:59:20.13 |
+73:29:02.5 |
HIP 63367 |
31.28 |
| 2026-08-11 12:00 |
12:59:30.14 |
+73:28:02.9 |
HIP 63367 |
30.33 |
| 2026-08-12 00:00 |
12:59:40.24 |
+73:27:03.6 |
HIP 63367 |
29.40 |
| 2026-08-12 12:00 |
12:59:50.45 |
+73:26:04.6 |
HIP 63367 |
28.50 |
| 2026-08-13 00:00 |
13:00:00.76 |
+73:25:05.9 |
HIP 63367 |
27.63 |
| 2026-08-13 12:00 |
13:00:11.16 |
+73:24:07.5 |
HIP 63367 |
26.80 |
| 2026-08-14 00:00 |
13:00:21.66 |
+73:23:09.3 |
HIP 63367 |
26.01 |
| 2026-08-14 12:00 |
13:00:32.26 |
+73:22:11.5 |
HIP 63367 |
25.25 |
| 2026-08-15 00:00 |
13:00:42.95 |
+73:21:14.1 |
HIP 63367 |
24.55 |
| 2026-08-15 12:00 |
13:00:53.74 |
+73:20:16.9 |
HIP 63367 |
23.89 |
| 2026-08-16 00:00 |
13:01:04.62 |
+73:19:20.0 |
HIP 63367 |
23.29 |
| 2026-08-16 12:00 |
13:01:15.60 |
+73:18:23.5 |
HIP 63367 |
22.75 |
| 2026-08-17 00:00 |
13:01:26.66 |
+73:17:27.3 |
HIP 63822 |
21.71 |
| 2026-08-17 12:00 |
13:01:37.82 |
+73:16:31.5 |
HIP 63822 |
20.48 |
| 2026-08-18 00:00 |
13:01:49.07 |
+73:15:35.9 |
HIP 63822 |
19.25 |
| 2026-08-18 12:00 |
13:02:00.40 |
+73:14:40.7 |
HIP 63822 |
18.02 |
| 2026-08-19 00:00 |
13:02:11.83 |
+73:13:45.9 |
HIP 63822 |
16.79 |